In an earlier post I described a relatively conservative and sensible approach to initiating a running programme. Going through a walk / run programme at the beginning of any period of running is a wise move no matter how young and fit you are and no matter how much prior running experience you have. Almost everyone who has ever run regularly has encountered some kind of musculoskeletal injury as a result of the biomechanical stresses of running compared to other activities. No one has perfect running biomechanics. High performance athletes spend countless hours working on their biomechanics partly to avoid injury and partly to increase efficiency, but most of us simply run. When we do so, small imbalances in posture and gait almost always lead to unequal loading of various muscles groups. Often when we are young these are simply handled without any issues but, with age or with a severe enough imbalance, injuries inevitably crop up making a gradual progression at any age a wise approach to avoid future problems.
What about after you are able to comfortably run for 30 - 40 minutes without stopping and you want to progress to greater running fitness? There are many, many approaches to increasing running performance but the most important place to start is with an analysis of your goals. Do you want to complete your first half marathon or marathon? Do you want to improve your 10km run time? Do you want to try to get back to your high-school personal best for the mile? All of these example goals will require vastly different approaches to training progression. However, in my opinion at least, there are three fundamental types of running workouts: 1) distance; 2) threshold; 3) intervals. These typically decrease in distance and increase in speed in that order. When working on distance you are, obviously, going to run longer distances but you'll have to do so at slower speeds than the other two types of workouts. Interval runs are typically very short (less than 1 mile) repetitive bouts of high or maximal-intensity work, and threshold runs fall in the middle. Increasing your fitness in all three areas is important for almost any running goal, but your focus will change depending on your specific goal(s).
It's not rocket science (or, as a colleague of mine likes to say, "rocket surgery") to figure out that training for distance races such as marathons or half-marathons requires a vast amount of distance work. The bulk of your training will involve a gradual increase in the distance you are able to run in one workout. A rough ball-park guideline on how much to progress in distance is no more than 10% per week. If you are able to run for 30 minutes this week, then next week's goal is to be able to run 33 minutes in a workout. The following week might take you to 35-36 minutes and so on. Building up to a 3 or 4 (or more) hour marathon will obviously take a while at this rate, especially since the rate of progression should probably decrease as your length of distance runs increases (all in an attempt to avoid injury and reach long-term goals gradually and consistently). The other two types of workouts, mixed into your training routine, will certainly help your distance performance, but you'll need to focus on distance work. More on this type of training later...
Threshold work is the least fun in my experience. Threshold, or more accurately anaerobic threshold, is that intensity at which you are no longer able to supply all your energy demands primarily through aerobic metabolism. Therefore, your body starts to rely more and more heavily on anaerobic metabolism. Unfortunately this comes at a heavy cost, both in efficiency and in the production of waste products such as lactic acid which cause that tell-tale burning feeling in your legs combined with extreme breathlessness. Running below your threshold intensity can be sustained for longer periods (such as in a distance workout). Once your intensity increases to above your threshold, you are on borrowed time and relatively quickly you'll have to slow down or stop. But running right at your anaerobic threshold will generally allow you to keep running for a reasonably extended period of time (say 30 minutes), but with gradually increasing fatigue and pain. In the end you'll have to slow down or stop, but the process of getting to that point will be slow and gradual (like some sort of Chinese torture). Threshold workouts typically last in the neighbourhood of 30 minutes and they are as high intensity as you can manage for that period of time. The goal is to gradually increase the speed that you can run for about 30 - 40 minutes. At first you might be able to sustain 7.5mph for 30 minutes of running. After some significant work and training, perhaps you manage to raise that sustainable speed to 8.0mph for 30 minutes, and so on. Threshold work is obviously critical for any sort of middle distance performance such as a 5km or 10km race, because that is the intensity you'll be running the race at.
Interval work involves very high intensity (above threshold) running for very short bouts (typically 5 minutes or less). The idea is to work as hard as you can for a given period of time, then take a few minutes of recovery at a much lower intensity, and then repeat the higher intensity work. This is repeated multiple times ranging anywhere from 2 or 3 repetitions up to 20 - 30 repetitions (for experienced, high performance runners). Normally, the way to initiate yourself into interval work is to start with longer intervals (say 5 minutes) and gradually, over weeks and months, decrease the length of the interval and increase the speed (as well as the number of repetitions). For 5 minute intervals, 2 or 3 repetitions may be enough to begin with, but eventually if you work your way to doing 1 or 2 minute intervals you may want 5 - 10 repetitions to get a good workout.
These are the three main fundamentals of running training. Each workout can likely fall into one of these three categories. Later on I'll explore the details of each.
23 July 2011
15 July 2011
Safely Starting an Exercise Programme
The last thing you want to do as you begin an exercise programme for health and fitness is to actually put your health at risk. Exercise does pose some health risks to various individuals. Anyone with an underlying cardiac condition, high blood pressure, diabetes (Type I or II), obesity, or other condition is strongly advised to consult with a physician prior to beginning any exercise programme. It is not a bad idea for any middle aged or older adult to do so whether they suspect they have a condition or not. Even young, apparently healthy people can have congenital conditions that might be exacerbated by exercise. Something as simple as undiagnosed exercise-induced asthma can cause significant problems.
The American College of Sports Medicine (ACSM) has an extensive risk classification system for beginning exercise, and a number of screening forms. Complete the ACSM's questionnaire on Preparticipation Screening below.
If you ticked two or more of the cardiovascular risk factors (male > 45 y, female > 55 y, you smoke, your blood pressure is greater than 140/90, you don't know your blood pressure, you take blood pressure medication, your cholesterol level is > 200 mg/dL, you don't know your cholesterol level, you have a close relative who had a heart attack before age 55 (father or brother) or age 65 (mother or sister), you are physically inactive (less than 30 min of activity on at least 3 days per week), you are more than 20 pounds overweight), then you should consult a physician before engaging in exercise.
The Canadian Society for Exercise Physiology (CSEP) also has a group of screening forms (PAR-Q or Physical Activity Readiness Questionnaire forms) for the general population (PAR-Q form), for use by a physician for those patients with positive PAR-Q forms (PARmed-X), and for pregnant women (PAR-Q for pregnancy). I have zoomed in on the main questions of the PAR-Q form below:
As you can see, the main concern from both of these screening forms is cardiovascular disease risk. Anyone with known high blood pressure, high cholesterol, or any known heart concern of any sort should never initiate an exercise programme without the supervision of a physician or qualified exercise specialist.
There are, of course, other risks to beginning an exercise programme. Transient muscle pain (DOMS or delayed onset muscle soreness) is likely. Musculoskeletal injuries are possible. Extreme fatigue may be experienced in the early stages of an exercise programme. But, all of these issues are less serious than the cardiovascular risks. Clear yourself of those risk factors first, then consider starting an exercise programme.
The American College of Sports Medicine (ACSM) has an extensive risk classification system for beginning exercise, and a number of screening forms. Complete the ACSM's questionnaire on Preparticipation Screening below.
The Canadian Society for Exercise Physiology (CSEP) also has a group of screening forms (PAR-Q or Physical Activity Readiness Questionnaire forms) for the general population (PAR-Q form), for use by a physician for those patients with positive PAR-Q forms (PARmed-X), and for pregnant women (PAR-Q for pregnancy). I have zoomed in on the main questions of the PAR-Q form below:
There are, of course, other risks to beginning an exercise programme. Transient muscle pain (DOMS or delayed onset muscle soreness) is likely. Musculoskeletal injuries are possible. Extreme fatigue may be experienced in the early stages of an exercise programme. But, all of these issues are less serious than the cardiovascular risks. Clear yourself of those risk factors first, then consider starting an exercise programme.
14 July 2011
Starting to Run from Scratch: Basic Walk / Run Progression
Running is one of the easiest, most inexpensive, and enjoyable ways to keep fit. The old adage about needing only a pair of shorts and a pair of running shoes to be fit for life has a lot of truth to it, but getting the most out of your running experience, avoiding injuries, building fitness gradually over time, and not getting bored all require some knowledge and planning. There are a multitude of books on running. Any major bookstore will have a large section in their fitness or sports section full of books on how to run, how to avoid running injuries, how to run your first marathon, etc. One of the classics is The Lore of Running by Tim Noakes, a South African physician, runner, and sometime exercise physiologist. The book is a heavyweight that covers the spectrum of issues including fitness, injuries, building volume, and a healthy dose of how exercise science relates to running. Every magazine rack also seems full of running magazines promising the best programmes for fitness, for your best time ever, for your first marathon, for running off your baby weight, for whatever goal you may dream up. But many (most) of these magazine articles neglect to start with the very basics. What do you do if you've never run much before and you want to start?
The main initial goals of anyone undertaking running for the first time is to avoid injuries and simply get to the point that they can actually run for a sustained period of time on a regular basis without injuring themselves. That’s it. No goals about marathons, half marathons, or completing community 10km runs. Just being able to run for 20 – 30 minutes at an easy pace on a regular basis. The number of weeks and months it may take to progress to this point will vary dramatically between individuals depending on prior running experience, overall fitness, joint health, age, and motivation.
A very basic framework for building up to being able to run regularly is progressing through a walk / run programme. Essentially this involves alternating walking with short periods of running within one session and then gradually increasing the duration of the running periods over time. The standard walk / run progression involves starting with a 30 minute walk and then introducing 30 seconds of running every five minutes. Each subsequent progression involves adding an additional 30 seconds of running in each five minute block within the 30 minutes. How quickly one progresses is entirely variable. As a basic framework example, if you were able to progress by 30 seconds of running every time you worked out, your progression would look like the following:
Day 1: 30 minute walk
Day 2: alternate 4.5 minutes of walk with 30 seconds of running for 30 minutes
Day 3: alternate 4 minutes of walk with 1 minute of running for 30 minutes
Day 4: alternate 3.5 minutes of walk with 1.5 minutes of running for 30 minutes
Day 5: alternate 3 minutes of walk with 2 minutes of running for 30 minutes
Day 6: alternate 2.5 minutes of walk with 2.5 minutes of running for 30 minutes
Day 7: alternate 2 minutes of walk with 3 minutes of running for 30 minutes
Day 8: alternate 1.5 minutes of walk with 3.5 minutes of running for 30 minutes
Day 9: alternate 1 minutes of walk with 4 minutes of running for 30 minutes
Day 10: alternate 30 seconds of walk with 4.5 minutes of running for 30 minutes
Day 11 run for 30 minutes
You can see that within 11 workouts you have progressed from being able to walk for 30 minutes to being able to run for 30 minutes. (These workouts would, of course, not be completed on subsequent days, but rather alternated with one or two days of rest and recovery so that the entire progression would take about 20 – 30 days). It cannot be emphasized strongly enough that this is a framework example progression that moves you from walking for 30 minutes to running for 30 minutes within a month, and not a standard protocol that everyone should use. This framework can be used to personalize your own walk / run programme, but a progression of this nature is likely only appropriate for someone with prior running experience getting back into running after an extended break, or perhaps someone who is very young, healthy, and otherwise relatively fit. Others might want to stretch out this progression significantly. It might take you six months or more to progress through this plan if you have never run on a regular basis before and if you are significantly out of shape. In order to stretch out the progression, simply spend multiple days at each stage until you are very comfortable with that stage before progressing to the next stage.
This basic framework is an example of the Principle of Progression at work. It allows an individual to progress slowly and methodically from walking to running. I would normally use this walk / run programme to get back into running after any extended break from running (e.g. a break longer than about 6 - 8 weeks), no matter how fit I was at the time (say with cycling or other activities). The main reason for such a careful progression is that running places significant biomechanical load and impact on the body, and by very gradually progressing through these stages you dramatically reduce the risk of an overuse injury early on in your running programme.
Remember, the goal of any running programme is to gradually progress through an increasing level of fitness and performance, not to suddenly try to beat your personal best time. As long as you are progressing with your fitness, then be patient and the results will come. Deviate from your scheduled progression and you're very likely to set yourself back in the long run by developing injuries (or burnout). It is more difficult than it sounds to stick to a progression. Often it gets exciting to see the improvements in fitness and you are often tempted to run to your potential all the time. DON'T. Almost every workout along a long-term progression will be below your actual abilities in an all-out run. Keep that in mind all the time and, again, so long as you are progressing from week to week, then you don't need to be running your best times in every single workout.
Remember, the goal of any running programme is to gradually progress through an increasing level of fitness and performance, not to suddenly try to beat your personal best time. As long as you are progressing with your fitness, then be patient and the results will come. Deviate from your scheduled progression and you're very likely to set yourself back in the long run by developing injuries (or burnout). It is more difficult than it sounds to stick to a progression. Often it gets exciting to see the improvements in fitness and you are often tempted to run to your potential all the time. DON'T. Almost every workout along a long-term progression will be below your actual abilities in an all-out run. Keep that in mind all the time and, again, so long as you are progressing from week to week, then you don't need to be running your best times in every single workout.
9 July 2011
Estimating Maximal Oxygen Uptake (VO2max)
The term VO2max refers to the maximal rate of oxygen consumption of the whole body. The human body consumes oxygen all the time (VO2), and the rate of consumption tops out when we are at our maximal work rate. Understanding of VO2max is critical to certain types of exercise training and performance, specifically aerobic exercise in which higher performance is generally directly related to a higher VO2max.
Measuring VO2max directly and accurately requires metabolic measurement equipment that measures the volume of air a person breathes as well as the fraction of oxygen inspired and expired with each breath. Typically this involves performing some graded exercise (gradually increasing intensity) over approximately 8 - 12 minutes until maximal exertion is reached, while breathing through some sort of mask. The most common place to get a direct measure of VO2max is at a university kinesiology department, some of which will offer a fee for service test. The cost is often $150 - $200 per test. Most aerobic athletes who are competing at university level or higher will likely have their VO2max tested on numerous occasions. Other professional athletes will also get tested on a regular basis (for example, most National Hockey League teams include a VO2max test in their annual battery of tests at fall training camp). But many recreational athletes will never have the opportunity to be tested in that way. Depending on your interest level in sports, it may be worth having such a test conducted at some point, but there are a few things you'll want to note before and after the test to help future estimates of fitness without having to pay for another test. (See below).
There are several ways to estimate VO2max without directly measuring it. None are perfectly accurate and all have some built in errors and assumptions that result from individual differences between people. The American College of Sports Medicine (ACSM) provides a prediction equation for oxygen uptake (VO2) based on running or walking speed. The equations are:
running VO2 = (0.2 x speed) + [(0.9 x grade) x speed] + 3.5
walking VO2 = (0.1 x speed) + [(1.8 x grade) x speed] + 3.5
speed is expressed in metres per minute (e.g. 10 mph = 268 m/min) and grade is expressed as a percentage (e.g. 2% on the treadmill = 0.02)
As an example, if the treadmill running speed is 8.0 mph (214.4 m/min) and the grade is 1% (0.01), then the running VO2 = 48.3 ml/kg/min, which means that, on average, each kilogram of body weight is consuming 48.3 ml of oxygen every minute.
Since measurement of VO2max requires that the exercise intensity is sustainable (i.e. not a short sprint that lasts only a few seconds), you can not simply find the fastest speed you can run on a treadmill and then assume that is your VO2max. Your body can supplement the energy supplied by aerobic systems anaerobically (without the presence of oxygen) for short periods. Therefore, for short bursts you are capable of running at speeds higher than the speed that corresponds to your VO2max. In theory, if you knew what speed corresponds to your VO2max, then you could use the equation above to estimate your VO2max. One way of estimating this speed is to find the speed that you can run at for 5 - 6 minutes and no longer. Most people with some degree of exercise training can sustain their VO2max intensity for this time period, but are completely exhausted at the end of it. So, if you are able to run at 10mph for 5 - 6 minutes but no longer then it is a good bet you are running at or close to your VO2max at 10mph. Simply taking that speed and plugging it into the ACSM equation will estimate your VO2max. It is just an estimate because, like all such equations, it is based on averages for a large population and there is some variation between people.
Of course, getting your VO2max measured directly once in a while is not a bad idea if you are serious about performance. But, before (or within a few days following) the test, also run through the calculation above. Find your estimated VO2max from the running speed you can sustain for 5 - 6 minutes as above. That way, when you also have the direct measure you'll have an idea how accurate the prediction equation is for you. If your calculated VO2max is 57 ml/kg/min and the direct measure is only 53 ml/kg/min, then in future estimations you'll know your are over-estimating by about 7.5% and can adjust accordingly. It is also worth doing a VO2max test at a time in your training when you are familiar with several times for various performances (e.g. 1 mile run time, 10km run time, half marathon, etc.). In that way, you'll know exactly how your performance is at a given VO2max. In future, you'll be able to use these performance times to estimate whether your VO2max is above of below where it was previously when measured directly. (Though performance and VO2max are not perfectly correlated due to a number of other performance factors, they do have quite a strong relationship).
Measuring VO2max directly and accurately requires metabolic measurement equipment that measures the volume of air a person breathes as well as the fraction of oxygen inspired and expired with each breath. Typically this involves performing some graded exercise (gradually increasing intensity) over approximately 8 - 12 minutes until maximal exertion is reached, while breathing through some sort of mask. The most common place to get a direct measure of VO2max is at a university kinesiology department, some of which will offer a fee for service test. The cost is often $150 - $200 per test. Most aerobic athletes who are competing at university level or higher will likely have their VO2max tested on numerous occasions. Other professional athletes will also get tested on a regular basis (for example, most National Hockey League teams include a VO2max test in their annual battery of tests at fall training camp). But many recreational athletes will never have the opportunity to be tested in that way. Depending on your interest level in sports, it may be worth having such a test conducted at some point, but there are a few things you'll want to note before and after the test to help future estimates of fitness without having to pay for another test. (See below).
There are several ways to estimate VO2max without directly measuring it. None are perfectly accurate and all have some built in errors and assumptions that result from individual differences between people. The American College of Sports Medicine (ACSM) provides a prediction equation for oxygen uptake (VO2) based on running or walking speed. The equations are:
running VO2 = (0.2 x speed) + [(0.9 x grade) x speed] + 3.5
walking VO2 = (0.1 x speed) + [(1.8 x grade) x speed] + 3.5
speed is expressed in metres per minute (e.g. 10 mph = 268 m/min) and grade is expressed as a percentage (e.g. 2% on the treadmill = 0.02)
As an example, if the treadmill running speed is 8.0 mph (214.4 m/min) and the grade is 1% (0.01), then the running VO2 = 48.3 ml/kg/min, which means that, on average, each kilogram of body weight is consuming 48.3 ml of oxygen every minute.
Since measurement of VO2max requires that the exercise intensity is sustainable (i.e. not a short sprint that lasts only a few seconds), you can not simply find the fastest speed you can run on a treadmill and then assume that is your VO2max. Your body can supplement the energy supplied by aerobic systems anaerobically (without the presence of oxygen) for short periods. Therefore, for short bursts you are capable of running at speeds higher than the speed that corresponds to your VO2max. In theory, if you knew what speed corresponds to your VO2max, then you could use the equation above to estimate your VO2max. One way of estimating this speed is to find the speed that you can run at for 5 - 6 minutes and no longer. Most people with some degree of exercise training can sustain their VO2max intensity for this time period, but are completely exhausted at the end of it. So, if you are able to run at 10mph for 5 - 6 minutes but no longer then it is a good bet you are running at or close to your VO2max at 10mph. Simply taking that speed and plugging it into the ACSM equation will estimate your VO2max. It is just an estimate because, like all such equations, it is based on averages for a large population and there is some variation between people.
Of course, getting your VO2max measured directly once in a while is not a bad idea if you are serious about performance. But, before (or within a few days following) the test, also run through the calculation above. Find your estimated VO2max from the running speed you can sustain for 5 - 6 minutes as above. That way, when you also have the direct measure you'll have an idea how accurate the prediction equation is for you. If your calculated VO2max is 57 ml/kg/min and the direct measure is only 53 ml/kg/min, then in future estimations you'll know your are over-estimating by about 7.5% and can adjust accordingly. It is also worth doing a VO2max test at a time in your training when you are familiar with several times for various performances (e.g. 1 mile run time, 10km run time, half marathon, etc.). In that way, you'll know exactly how your performance is at a given VO2max. In future, you'll be able to use these performance times to estimate whether your VO2max is above of below where it was previously when measured directly. (Though performance and VO2max are not perfectly correlated due to a number of other performance factors, they do have quite a strong relationship).
4 July 2011
Estimating Exercise Intensity
If every workout has a goal, then the duration and intensity of the workout need to be clearly defined and regulated. The duration is as easy as monitoring a stopwatch, but the intensity is a bit more complex. If we assume for the moment that we're talking about continuous exercise modes such as running and cycling rather than intermittent exercise such as most strength training, then we're talking about working at a given intensity throughout the workout (or at least at varying intensities through various portions of the workout). If you know that you want a particular run of 30 minutes to be at 80% intensity, what does that mean and how do you gauge your intensity?
When it comes to doing work such as exercise everyone has both a resting and a maximal metabolic rate. Metabolic rate is simply the rate at which you can turn over energy in your whole metabolism (mostly your skeletal muscles during exercise). The higher your maximal metabolic rate, the higher your exercise capacity. Typically in exercise physiology metabolic rate is measured as oxygen consumption (VO2) since oxygen is the ultimate electron acceptor in the metabolic processes that occur in the cells. The more energy you can turn over the more oxygen you require in the cells and therefore the more oxygen you consume. Oxygen consumption is typically measured in either litres per minute (l/min) or more usefully in millilitres per minute per kilogram of body mass (ml/kg/min). Resting metabolic rate is typically considered to be about 3.5 ml/kg/min and maximal values range dramatically with genetics, training, gender, body composition, and age, but are typically in the range of 30 - 80 ml/kg/min in healthy young adults. If you are in the 30 range then you are probably not involved in any regular exercise training and you might be out of breath walking up a few flights of stairs. If your peak is over 55 then you likely train very regularly and are relatively fit compared to the average person. If your peak oxygen consumption is over 70 then you are almost certainly a trained endurance athlete. Regardless, each person is capable of working at a given percentage of maximum rate and in theory at least 80% will feel similar regardless of how high your maximum is.
But measuring oxygen consumption during exercise requires specialized and expensive laboratory equipment and is not at all practical for training purposes. Fortunately, heart rate, which is relatively easy to measure during exercise, tends to be more or less linearly related to exercise intensity and oxygen consumption.
This figure shows the relationship between heart rate and exercise intensity (power output on a bicycle ergometer) during a test of progressively increasing intensity to max in a young, healthy male cyclist. Note the roughly linear relationship between the two variables.
Similarly to metabolic rate, everyone has a resting and maximal heart rate. Finding your resting heart rate is relatively straight forward. Ideally it should be measured first thing in the morning before eating or drinking coffee and while still lying supine. Find your radial or carotid pulse and count for a full minute. Resting heart rates in healthy young adults are typically in the range of 50 - 100 beats per minute (bpm). Over 100 bpm (tachycardia) is unusual and might indicate an abnormality. A low resting heart rate below 60 bpm (bradycardia) may also be symptomatic of an abnormality but in reality many individuals have low resting heart rates, and it is not uncommon for endurance athletes to have a resting heart rate below 40 bpm. Measuring your maximal heart rate requires taking this same measure during maximal exercise. But, the exercise must be progressive in nature to allow time for elevation of heart rate rather than all-out for only a few seconds. The best way to actually measure maximal heart rate is to wear a heart rate monitor and progress on a treadmill through one minute stages of increasing speed and treadmill grade until you are running at a high speed and grade and cannot continue (this requires some practice and skill if you are not familiar with high speed treadmill running and is not recommended for novices). There are several ways of estimating maximal heart rate, but the most commonly used one is to simply subtract your age from 220, such that a 20 year old would have an estimated maximal heart rate of 200 bpm.
So, once you have measured and estimated your resting and maximal heart rates, you know the range with which you have to work. It is now simple arithmetic to estimate the intensity that corresponds to a given heart rate. But, keep in mind that your resting heart rate is not zero so you should not simply multiply your desired intensity by your maximal heart rate. Instead, multiply your desired intensity by the difference between maximal and resting heart rates and then add it to the resting value:
exercise HR = [intensity % x (HRmax - HRrest)] + HR rest
For example, if your resting heart rate is 60 bpm and your maximal is 200 bpm and you want to work at 80%, then your desired workout heart rate is calculated as:
exercise HR = [0.80 x (200 - 60)] + 60 = 172 bpm
In reality the relationship between exercise intensity and heart rate is not perfectly linear nor is it perfectly consistent between workouts or over training periods. Metabolic rate is linearly related to exercise intensity, but the rate of oxygen consumption for a given intensity may vary some with training as the body becomes more efficient. In addition, the amount of blood pumped through the heart, delivering oxygen is called cardiac output and is the product of heart rate and stroke volume (the volume of blood pumped each beat). Since stroke volume varies with a number of factors (intensity, hydration, temperature, etc.) the relationship between heart rate and intensity is not perfect. Heart rate also tends to drift upwards at a given exercise intensity within one workout (cardiac drift). And, further, heart rate is affected by many factors including things like caffeine ingestion. So there are a number of potential errors that might shift the roughly straight line on the figure above up or down in one workout compared to the next, meaning that one should be cautious in putting too much stock in very specific workout heart rates. However, heart rate is a relatively valid tool to estimate exercise intensity.
When it comes to doing work such as exercise everyone has both a resting and a maximal metabolic rate. Metabolic rate is simply the rate at which you can turn over energy in your whole metabolism (mostly your skeletal muscles during exercise). The higher your maximal metabolic rate, the higher your exercise capacity. Typically in exercise physiology metabolic rate is measured as oxygen consumption (VO2) since oxygen is the ultimate electron acceptor in the metabolic processes that occur in the cells. The more energy you can turn over the more oxygen you require in the cells and therefore the more oxygen you consume. Oxygen consumption is typically measured in either litres per minute (l/min) or more usefully in millilitres per minute per kilogram of body mass (ml/kg/min). Resting metabolic rate is typically considered to be about 3.5 ml/kg/min and maximal values range dramatically with genetics, training, gender, body composition, and age, but are typically in the range of 30 - 80 ml/kg/min in healthy young adults. If you are in the 30 range then you are probably not involved in any regular exercise training and you might be out of breath walking up a few flights of stairs. If your peak is over 55 then you likely train very regularly and are relatively fit compared to the average person. If your peak oxygen consumption is over 70 then you are almost certainly a trained endurance athlete. Regardless, each person is capable of working at a given percentage of maximum rate and in theory at least 80% will feel similar regardless of how high your maximum is.
But measuring oxygen consumption during exercise requires specialized and expensive laboratory equipment and is not at all practical for training purposes. Fortunately, heart rate, which is relatively easy to measure during exercise, tends to be more or less linearly related to exercise intensity and oxygen consumption.
Similarly to metabolic rate, everyone has a resting and maximal heart rate. Finding your resting heart rate is relatively straight forward. Ideally it should be measured first thing in the morning before eating or drinking coffee and while still lying supine. Find your radial or carotid pulse and count for a full minute. Resting heart rates in healthy young adults are typically in the range of 50 - 100 beats per minute (bpm). Over 100 bpm (tachycardia) is unusual and might indicate an abnormality. A low resting heart rate below 60 bpm (bradycardia) may also be symptomatic of an abnormality but in reality many individuals have low resting heart rates, and it is not uncommon for endurance athletes to have a resting heart rate below 40 bpm. Measuring your maximal heart rate requires taking this same measure during maximal exercise. But, the exercise must be progressive in nature to allow time for elevation of heart rate rather than all-out for only a few seconds. The best way to actually measure maximal heart rate is to wear a heart rate monitor and progress on a treadmill through one minute stages of increasing speed and treadmill grade until you are running at a high speed and grade and cannot continue (this requires some practice and skill if you are not familiar with high speed treadmill running and is not recommended for novices). There are several ways of estimating maximal heart rate, but the most commonly used one is to simply subtract your age from 220, such that a 20 year old would have an estimated maximal heart rate of 200 bpm.
So, once you have measured and estimated your resting and maximal heart rates, you know the range with which you have to work. It is now simple arithmetic to estimate the intensity that corresponds to a given heart rate. But, keep in mind that your resting heart rate is not zero so you should not simply multiply your desired intensity by your maximal heart rate. Instead, multiply your desired intensity by the difference between maximal and resting heart rates and then add it to the resting value:
exercise HR = [intensity % x (HRmax - HRrest)] + HR rest
For example, if your resting heart rate is 60 bpm and your maximal is 200 bpm and you want to work at 80%, then your desired workout heart rate is calculated as:
exercise HR = [0.80 x (200 - 60)] + 60 = 172 bpm
In reality the relationship between exercise intensity and heart rate is not perfectly linear nor is it perfectly consistent between workouts or over training periods. Metabolic rate is linearly related to exercise intensity, but the rate of oxygen consumption for a given intensity may vary some with training as the body becomes more efficient. In addition, the amount of blood pumped through the heart, delivering oxygen is called cardiac output and is the product of heart rate and stroke volume (the volume of blood pumped each beat). Since stroke volume varies with a number of factors (intensity, hydration, temperature, etc.) the relationship between heart rate and intensity is not perfect. Heart rate also tends to drift upwards at a given exercise intensity within one workout (cardiac drift). And, further, heart rate is affected by many factors including things like caffeine ingestion. So there are a number of potential errors that might shift the roughly straight line on the figure above up or down in one workout compared to the next, meaning that one should be cautious in putting too much stock in very specific workout heart rates. However, heart rate is a relatively valid tool to estimate exercise intensity.
How Much Exercise for Health?
How much physical activity is needed for health benefits? Is more always better? What type of activity has the best health benefits? What intensity of exercise has the best health benefits? Can too much exercise be unhealthy?
The answers to all of these questions have some known and some unknown components. As long as research is being conducted on physical activity and health, then we won't have all the answers. Depending on whether you are a cancer survivor, are living with Type II diabetes, are obese, have a genetic predisposition to heart disease, or are a full-time athlete is likely to have a profound effect on the answers to these types of questions. Finding the right combination of frequency, intensity, and time (F.I.T.) of physical activity that is personalized to you for the best health benefits is no simple task. But, thankfully there are a number of useful and generally safe guidelines and recommendations available.
In North America, two organizations that preoccupy themselves with physical activity and health are the American College of Sports Medicine (ACSM) and the Canadian Society for Exercise Physiology (CSEP). Members of both of these organizations are involved in research, education, and public service in relation to physical activity and health, and both organizations provide specific guidelines on the recommended amounts and intensities of exercise that are beneficial to health.
Many chronic diseases are multi-factorial in their causes. Typically, things such as genetics, smoking, physical activity, and nutrition are all contributing factors in determining your risk of a particular chronic lifestyle-related disease (e.g. Type II diabetes, heart disease, stroke, some cancers, chronic obstructive pulmonary disease or COPD). The goal of including regular physical activity in your lifestyle with respect to heatlh is really two-fold: 1) to remove physical inactivity as a risk factor for these types of diseases; and 2) to increase awareness of all lifestyle factors and increase your chances of an overall healthy lifestyle (people who are active are also more likely to be proactive about not smoking, about proper nutrition, etc.). So, the relevant question becomes, how much physical activity does it take to remove physical inactivity as a risk factor for chronic diseases? As you may imagine, the answer varies with the person and with the condition, but the typical guidelines for healthy individuals are as follows.
ACSM's webpage provides a link to the physical activity guidelines for Americans. As you can see, the ACSM / American Heart Association guidlines are essentially to include 150 minutes of moderate intensity exercise per week. This is roughly broken down into recommendations of 30 minutes of moderate intensity cardio work 5 days per week OR 20 minutes of intense cardio work 3 days per week, AND 8 - 10 strength training exercises per week with 8 - 12 repetitions of each exercise.
Similarly, the CSEP webpage has a link to their physical activity guidelines for Canadians. Adults (aged 18 - 64) are recommended to achieve at least 150 minutes of moderate to vigorous intensity aerobic activity (i.e. cardio work) per week, in bouts of 10 minutes or more, AND 2 days per week of muscle and bone strengthening exercises (resistance work).
There is some debate over whether more than this has health benefits, and the reason it continues to be debated is likely because it depends which aspect of health you are referring to. For obesity prevention, undoubtedly greater acccumulation of activity is better, but for someone at risk for arthritis that might come at a cost. Chronic conditions like heart disease likely have a threshold of physical activity above which more exercise is unlikely to add much more of a preventive effect. But even this is debated and is likely individually variable. The above recommendations are the minimums, and you'll likely reduce your disease risk significantly if you meet those recommendations.
What is meant by moderate or vigorous intensity? The ACSM has a few links on intensity of exercise and CSEP defines moderate intensity activity as those that cause you to sweat a little and breathe harder such as brisk walking and bike riding, and vigorous intesnity activities as those that cause you to sweat and be out of breathe such as jogging and cross-country skiing. The easiest way to assess exercise intensty relatively accurately is to monitor your heart rate during exercise (this can be done either by pausing the activity and counting your pulse for 10 or 15 seconds and multiplying by 6 or 4 respectively) or by wearing a heart rate monitor. (More on heart rate and exercise intensity in a later post).
The answers to all of these questions have some known and some unknown components. As long as research is being conducted on physical activity and health, then we won't have all the answers. Depending on whether you are a cancer survivor, are living with Type II diabetes, are obese, have a genetic predisposition to heart disease, or are a full-time athlete is likely to have a profound effect on the answers to these types of questions. Finding the right combination of frequency, intensity, and time (F.I.T.) of physical activity that is personalized to you for the best health benefits is no simple task. But, thankfully there are a number of useful and generally safe guidelines and recommendations available.
In North America, two organizations that preoccupy themselves with physical activity and health are the American College of Sports Medicine (ACSM) and the Canadian Society for Exercise Physiology (CSEP). Members of both of these organizations are involved in research, education, and public service in relation to physical activity and health, and both organizations provide specific guidelines on the recommended amounts and intensities of exercise that are beneficial to health.
Many chronic diseases are multi-factorial in their causes. Typically, things such as genetics, smoking, physical activity, and nutrition are all contributing factors in determining your risk of a particular chronic lifestyle-related disease (e.g. Type II diabetes, heart disease, stroke, some cancers, chronic obstructive pulmonary disease or COPD). The goal of including regular physical activity in your lifestyle with respect to heatlh is really two-fold: 1) to remove physical inactivity as a risk factor for these types of diseases; and 2) to increase awareness of all lifestyle factors and increase your chances of an overall healthy lifestyle (people who are active are also more likely to be proactive about not smoking, about proper nutrition, etc.). So, the relevant question becomes, how much physical activity does it take to remove physical inactivity as a risk factor for chronic diseases? As you may imagine, the answer varies with the person and with the condition, but the typical guidelines for healthy individuals are as follows.
ACSM's webpage provides a link to the physical activity guidelines for Americans. As you can see, the ACSM / American Heart Association guidlines are essentially to include 150 minutes of moderate intensity exercise per week. This is roughly broken down into recommendations of 30 minutes of moderate intensity cardio work 5 days per week OR 20 minutes of intense cardio work 3 days per week, AND 8 - 10 strength training exercises per week with 8 - 12 repetitions of each exercise.
Similarly, the CSEP webpage has a link to their physical activity guidelines for Canadians. Adults (aged 18 - 64) are recommended to achieve at least 150 minutes of moderate to vigorous intensity aerobic activity (i.e. cardio work) per week, in bouts of 10 minutes or more, AND 2 days per week of muscle and bone strengthening exercises (resistance work).
There is some debate over whether more than this has health benefits, and the reason it continues to be debated is likely because it depends which aspect of health you are referring to. For obesity prevention, undoubtedly greater acccumulation of activity is better, but for someone at risk for arthritis that might come at a cost. Chronic conditions like heart disease likely have a threshold of physical activity above which more exercise is unlikely to add much more of a preventive effect. But even this is debated and is likely individually variable. The above recommendations are the minimums, and you'll likely reduce your disease risk significantly if you meet those recommendations.
What is meant by moderate or vigorous intensity? The ACSM has a few links on intensity of exercise and CSEP defines moderate intensity activity as those that cause you to sweat a little and breathe harder such as brisk walking and bike riding, and vigorous intesnity activities as those that cause you to sweat and be out of breathe such as jogging and cross-country skiing. The easiest way to assess exercise intensty relatively accurately is to monitor your heart rate during exercise (this can be done either by pausing the activity and counting your pulse for 10 or 15 seconds and multiplying by 6 or 4 respectively) or by wearing a heart rate monitor. (More on heart rate and exercise intensity in a later post).
Training with a Goal
Setting goals is, of course, a recommended approach to many things in life and exercise training is no different. While there are potentially some scenarios where exercising without specific goals is beneficial (such as recovery from burnout or overtraining), setting goals is a crucial part of getting the most out of your workouts as well as being efficient with the time you put in. There are many different approaches and recommendations to goal setting, but a number of guidelines are common. Goals should always be specific and personal to the individual, realistic but challenging, and should include both short and long-term outcomes.
One of the more common mistakes in goal-setting is to focus too much on the long-term rather than setting series of shorter term goals as steps towards that long-term goal. For example, wanting to run the mile in a specific time (say 4, 5, or 6 minutes depending on your fitness, dedication, ability, and age) is a great long-term goal, but if you currently run the mile in 7:35 and you want to get down to 5 minutes flat you're gonig to need a lot of steps along the way with a specific timeline. Starting off by knocking 5 seconds per mile off your time every month might be realistic to begin with, but as you get closer to the 5 minute mark it certainly won't be. Anticipating this (making the goals realistic) is key to staying on task and not giving up hope. In addition, knowing that each month requires a new time provides short-term accountability. Dreams of one day running a 5 minute mile are likely to remain just that unless there are short term goals along the way. Typically in my own workouts I go quite a bit shorter term with my goals in that every workout will have a goal. This is a utilization of the Principle of Progression in that in theory each workout progresses you ever so slightly towards your long-term goal. And, checking off a goal at the end of every workout really makes a difference to getting motivated for the next workout. For most training goals it is not possible to actually progress with every single workout (i.e. run faster, lift a heavier weight, cycle further than the previous workout). But, if you have a plan for how many workouts it will take to progress to the next stage, then each workout is a milestone along that very specific progression.
Going back to the running example, it may be that you reach the point at which you are running a 6 minute mile, but you find you are only able to reduce your mile time by 5 seconds every 4 workouts. Each workout in that case becomes a progression of 1, 2, 3, and 4 towards the next reduction in time. In that way, each and every workout has an achievable goal, rather than spending a week training and hoping to check off a reduction in time at some point during the week.
I have typically found that a workout without a specific goal is a wasted workout. In the past I have often had categories of workouts (speed, endurance, threshold training, etc.) and cycled through them. But I've also often found that I become stagnant by only doing so. There is enough variation within the week of training to keep you interested and motivated, but from week toweek you often find yourself simply completing the same old workouts and forgetting about progression.
A great way to start setting up short-term goals is to write down your long-term goal, figure out where you are right now (by performing a specific type of fitness test appropriate to the goal), estimate how long it will take you to realistically achieve your long-term goal, and then divide the difference by the number of weeks. Setting up a computer spreadsheet can be really helpful in this manner as it allows you to fill in boxes as you go. Of course, in reality the progression of fitness is not linear, injuries, illnesses, and life in general all get in the way, and so you'll find that the progression varies from your original timeline. But it is still crucial to have the timeline to begin with and then adjust it as needed.
One of the more common mistakes in goal-setting is to focus too much on the long-term rather than setting series of shorter term goals as steps towards that long-term goal. For example, wanting to run the mile in a specific time (say 4, 5, or 6 minutes depending on your fitness, dedication, ability, and age) is a great long-term goal, but if you currently run the mile in 7:35 and you want to get down to 5 minutes flat you're gonig to need a lot of steps along the way with a specific timeline. Starting off by knocking 5 seconds per mile off your time every month might be realistic to begin with, but as you get closer to the 5 minute mark it certainly won't be. Anticipating this (making the goals realistic) is key to staying on task and not giving up hope. In addition, knowing that each month requires a new time provides short-term accountability. Dreams of one day running a 5 minute mile are likely to remain just that unless there are short term goals along the way. Typically in my own workouts I go quite a bit shorter term with my goals in that every workout will have a goal. This is a utilization of the Principle of Progression in that in theory each workout progresses you ever so slightly towards your long-term goal. And, checking off a goal at the end of every workout really makes a difference to getting motivated for the next workout. For most training goals it is not possible to actually progress with every single workout (i.e. run faster, lift a heavier weight, cycle further than the previous workout). But, if you have a plan for how many workouts it will take to progress to the next stage, then each workout is a milestone along that very specific progression.
Going back to the running example, it may be that you reach the point at which you are running a 6 minute mile, but you find you are only able to reduce your mile time by 5 seconds every 4 workouts. Each workout in that case becomes a progression of 1, 2, 3, and 4 towards the next reduction in time. In that way, each and every workout has an achievable goal, rather than spending a week training and hoping to check off a reduction in time at some point during the week.
I have typically found that a workout without a specific goal is a wasted workout. In the past I have often had categories of workouts (speed, endurance, threshold training, etc.) and cycled through them. But I've also often found that I become stagnant by only doing so. There is enough variation within the week of training to keep you interested and motivated, but from week toweek you often find yourself simply completing the same old workouts and forgetting about progression.
A great way to start setting up short-term goals is to write down your long-term goal, figure out where you are right now (by performing a specific type of fitness test appropriate to the goal), estimate how long it will take you to realistically achieve your long-term goal, and then divide the difference by the number of weeks. Setting up a computer spreadsheet can be really helpful in this manner as it allows you to fill in boxes as you go. Of course, in reality the progression of fitness is not linear, injuries, illnesses, and life in general all get in the way, and so you'll find that the progression varies from your original timeline. But it is still crucial to have the timeline to begin with and then adjust it as needed.
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