Cardio Tip: Interval Training
In simple terms, interval training is a method of conditioning that alternates periods of work with periods of recovery—it’s the opposite of steady state cardio. Interval training develops aerobic capacity better than steady state aerobic training. The fastest way to raise VO2 max, our standard measure of aerobic fitness is through interval training. This post will specifically be about HIIT (high intensity interval training). HIIT is intense. HIIT is hard. HIIT is uncomfortable. So, why do it? The hard is what makes it so great. HIIT torches calories, blasts fat, raises metabolic rate, preserves muscle and generates EPOC (post exercise oxygen consumption = caloric "after burn" resulting in higher caloric expenditure).
Please note: if you are just starting out, don't jump into doing HIIT. HIIT shoots the heart rate up to high levels and as the name says, is very "high intensity". HIIT may or may not be safe for you so please check with your health care provider before adding it to your exercise plan. I advise anyone who is new to exercise to consider training under a certified and experienced fitness coach.
What about steady state cardio? Steady state cardio definitely has its place— it's great for recovery (always training at high intensity without recovery or without some lower intensity days may lead to overtraining, burn out, or even injury). If you’re an endurance athlete, then long steady state training is very important. Also, if you're just starting out, coming from a sedentary lifestyle, or are returning from an injury, then start first by building a basic foundation of cardio training using a non-impact form of steady state cardio at an intensity that is appropriate for you.
Back to interval training...
The complicated part of interval training is figuring out the rest and work ratios. But it doesn’t have to be complicated if you use heart rate.
I prefer heart rate based methods of dictating work to rest ratios as opposed to arbitrary time based intervals (example: 20 seconds on / 10 seconds off) because with time based intervals, we have no idea what’s happening inside the body and we may either work TOO hard or not hard enough—it’s easy to either over work and under rest or under work and over rest. Get yourself a heart rate monitor and use that — to use this method, have an idea of your max heart rate and select an appropriate recovery heart rate—I use 60% of theoretical max heart rate as my recovery. Note—if you use a HR calculator/formula to calculate your max HR, understand that at least 70% of the population does not fit into the theoretical calculations of the commonly used 220–age maximum heart rate formula. My actual max HR is higher than the formula based max HR for my age—I know this because, well I’ve exceeded the formula based maxHR and I’m still here to blog about it (but I'm not recommending that you push yourself to potentially unsafe levels). Do the formula based version anyway to have a ballpark idea. Note your heart rate immediately after completing your first hard work interval. During a HIIT work effort, strive for 80% or slightly more of your estimated max HR (but stay safe and do what is appropriate for you). The recovery is set by the time it takes to return back to the recovery heart rate (~55-60% max HR). You’ll notice that initial recovery after the first interval may be rapid, but subsequent intervals may require slightly longer rest periods. So, your work time AND rest time are dictated by heart rate. If I'm pushing a sled and my heart rate hits 80-85% when I'm half way down the turf, then I stop pushing and recover back down to 55-60% before I start the next push effort. Note: don't come to a dead stop after hitting such a high heart rate. Recovery doesn't mean standing still. When you rest, keep moving, but move at a low intensity. I do a recovery walk up and down the turf while my heart rate recovers.
(*IMPORTANT: please see the paragraph below on exercise, heart rate, and medication)
Alternative to heart rate method: RPE (Rate of Perceived Exertion)
Scale of 1-10: 1 is least difficult (just above rest) and 10 is the most difficult (max effort).
On a 1-10 scale of perceived exertion, high intensity can be considered anything over an effort level of 7. During recovery periods, recover to a RPE of around 4.
How many intervals should you do? Start small and build up—your first several sessions might include only 3 total intervals. And then, you might add an extra interval for several more sessions. Gradually, you can build up your total number of intervals. Note: up to 20-30 total HIIT session minutes is sufficient (rest periods included). If I am doing a longer session (such as a 45 minute group exercise HIIT class at the gym), we do not spend 45 solid minutes at a HIIT level. This entire period of time includes the warm up, workout with rest periods and the cool down/stretch period. Throughout a 45 minute to one-hour HIIT workout, you want to spend around 10 to 20 minutes at high intensity levels to see results.
When to do it? Do it when it works best for you. You can do stand alone HIIT workouts OR you can take on a shorter HIIT session following a strength training session. I usually do 10-15 total minutes right after a strength training workout (rest is included in the total time so actual work time might only be 5-7 minutes). Alternatively, if I am doing a stand alone HIIT workout, I might take a 45 minute HIIT style group exercise class OR I might do a 20-30 minute HIIT ride on my Peloton app.
More is not better when working at this level of intensity. Limit yourself to one or two HIIT style workouts per week on non-consecutive days. If your body is ready for more, you can add a third day, but always listen to your body.
Find a modality you enjoy—I love sled push sprints. The AirDyne Bike is great too—it’s probably one of the best modalities because it’s non-impact, safe for everyone and uses both the legs & arms effectively raising heart rate. Mix it up though—don’t always do the same thing—have a few options to rotate through—battle ropes and sleds, treadmill or track sprints, Assault Bike (AirDyne) sprints, etc. I do not recommend elliptical machines or stair climbers for HIIT/interval training.
VERY IMPORTANT— WARM UP THOROUGHLY BEFORE INTERVAL TRAINING. The more intense the workout will be, the longer and more thorough the warmup needs to be!
*EXERCISE AND MEDICATION MAY REQUIRE YOU TO ADJUST YOUR HEART RATE.
For those in this category, it may be better to use the RPE method vs. Heart Rate.
A common example is a group of drugs called beta-blockers, prescribed for patients with heart problems and high blood pressure. This drug reduces both the resting and exercise heart rate, although not always by the same amount. In some cases, a person can workout much harder without the heart rate elevating even into the aerobic zone. In this case, exercising at 125 beats per minute, for example, may be the same as 155 without the medication—so if your max aerobic heart rate is 140, you can easily be overtraining at 125. In fact, some people are unable to attain their max aerobic heart rate while on a beta-blocker. Anti-arrhythmic drugs, calcium channel blockers, and other medications can sometimes reduce exercise heart rate as well. If you’re taking any prescription or over-the-counter drug, you should know whether it affects the heart rate. Some drugs raise the heart rate. These include thyroid medication, Ritalin and other amphetamines, and even caffeine, which is found in certain cold remedies, pain relievers, and, of course, coffee, tea, and some sodas. These drugs will often cause higher exercise heart rates, forcing you to slow down to maintain your maximum aerobic heart rate. This means that by following your heart rate you may have to reduce your exercise intensity.
NOTE: Before beginning any training regimen, make sure it is medically safe for you to do so. If you have any injury, disease, disability or other concerns about starting an exercise program, consult your healthcare provider first.
Questions always welcomed! And I’m always happy to take you through a conditioning workout!
In simple terms, interval training is a method of conditioning that alternates periods of work with periods of recovery—it’s the opposite of steady state cardio. Interval training develops aerobic capacity better than steady state aerobic training. The fastest way to raise VO2 max, our standard measure of aerobic fitness is through interval training. This post will specifically be about HIIT (high intensity interval training). HIIT is intense. HIIT is hard. HIIT is uncomfortable. So, why do it? The hard is what makes it so great. HIIT torches calories, blasts fat, raises metabolic rate, preserves muscle and generates EPOC (post exercise oxygen consumption = caloric "after burn" resulting in higher caloric expenditure).
Please note: if you are just starting out, don't jump into doing HIIT. HIIT shoots the heart rate up to high levels and as the name says, is very "high intensity". HIIT may or may not be safe for you so please check with your health care provider before adding it to your exercise plan. I advise anyone who is new to exercise to consider training under a certified and experienced fitness coach.
What about steady state cardio? Steady state cardio definitely has its place— it's great for recovery (always training at high intensity without recovery or without some lower intensity days may lead to overtraining, burn out, or even injury). If you’re an endurance athlete, then long steady state training is very important. Also, if you're just starting out, coming from a sedentary lifestyle, or are returning from an injury, then start first by building a basic foundation of cardio training using a non-impact form of steady state cardio at an intensity that is appropriate for you.
Back to interval training...
The complicated part of interval training is figuring out the rest and work ratios. But it doesn’t have to be complicated if you use heart rate.
I prefer heart rate based methods of dictating work to rest ratios as opposed to arbitrary time based intervals (example: 20 seconds on / 10 seconds off) because with time based intervals, we have no idea what’s happening inside the body and we may either work TOO hard or not hard enough—it’s easy to either over work and under rest or under work and over rest. Get yourself a heart rate monitor and use that — to use this method, have an idea of your max heart rate and select an appropriate recovery heart rate—I use 60% of theoretical max heart rate as my recovery. Note—if you use a HR calculator/formula to calculate your max HR, understand that at least 70% of the population does not fit into the theoretical calculations of the commonly used 220–age maximum heart rate formula. My actual max HR is higher than the formula based max HR for my age—I know this because, well I’ve exceeded the formula based maxHR and I’m still here to blog about it (but I'm not recommending that you push yourself to potentially unsafe levels). Do the formula based version anyway to have a ballpark idea. Note your heart rate immediately after completing your first hard work interval. During a HIIT work effort, strive for 80% or slightly more of your estimated max HR (but stay safe and do what is appropriate for you). The recovery is set by the time it takes to return back to the recovery heart rate (~55-60% max HR). You’ll notice that initial recovery after the first interval may be rapid, but subsequent intervals may require slightly longer rest periods. So, your work time AND rest time are dictated by heart rate. If I'm pushing a sled and my heart rate hits 80-85% when I'm half way down the turf, then I stop pushing and recover back down to 55-60% before I start the next push effort. Note: don't come to a dead stop after hitting such a high heart rate. Recovery doesn't mean standing still. When you rest, keep moving, but move at a low intensity. I do a recovery walk up and down the turf while my heart rate recovers.
(*IMPORTANT: please see the paragraph below on exercise, heart rate, and medication)
Alternative to heart rate method: RPE (Rate of Perceived Exertion)
Scale of 1-10: 1 is least difficult (just above rest) and 10 is the most difficult (max effort).
On a 1-10 scale of perceived exertion, high intensity can be considered anything over an effort level of 7. During recovery periods, recover to a RPE of around 4.
How many intervals should you do? Start small and build up—your first several sessions might include only 3 total intervals. And then, you might add an extra interval for several more sessions. Gradually, you can build up your total number of intervals. Note: up to 20-30 total HIIT session minutes is sufficient (rest periods included). If I am doing a longer session (such as a 45 minute group exercise HIIT class at the gym), we do not spend 45 solid minutes at a HIIT level. This entire period of time includes the warm up, workout with rest periods and the cool down/stretch period. Throughout a 45 minute to one-hour HIIT workout, you want to spend around 10 to 20 minutes at high intensity levels to see results.
When to do it? Do it when it works best for you. You can do stand alone HIIT workouts OR you can take on a shorter HIIT session following a strength training session. I usually do 10-15 total minutes right after a strength training workout (rest is included in the total time so actual work time might only be 5-7 minutes). Alternatively, if I am doing a stand alone HIIT workout, I might take a 45 minute HIIT style group exercise class OR I might do a 20-30 minute HIIT ride on my Peloton app.
More is not better when working at this level of intensity. Limit yourself to one or two HIIT style workouts per week on non-consecutive days. If your body is ready for more, you can add a third day, but always listen to your body.
Find a modality you enjoy—I love sled push sprints. The AirDyne Bike is great too—it’s probably one of the best modalities because it’s non-impact, safe for everyone and uses both the legs & arms effectively raising heart rate. Mix it up though—don’t always do the same thing—have a few options to rotate through—battle ropes and sleds, treadmill or track sprints, Assault Bike (AirDyne) sprints, etc. I do not recommend elliptical machines or stair climbers for HIIT/interval training.
VERY IMPORTANT— WARM UP THOROUGHLY BEFORE INTERVAL TRAINING. The more intense the workout will be, the longer and more thorough the warmup needs to be!
*EXERCISE AND MEDICATION MAY REQUIRE YOU TO ADJUST YOUR HEART RATE.
For those in this category, it may be better to use the RPE method vs. Heart Rate.
A common example is a group of drugs called beta-blockers, prescribed for patients with heart problems and high blood pressure. This drug reduces both the resting and exercise heart rate, although not always by the same amount. In some cases, a person can workout much harder without the heart rate elevating even into the aerobic zone. In this case, exercising at 125 beats per minute, for example, may be the same as 155 without the medication—so if your max aerobic heart rate is 140, you can easily be overtraining at 125. In fact, some people are unable to attain their max aerobic heart rate while on a beta-blocker. Anti-arrhythmic drugs, calcium channel blockers, and other medications can sometimes reduce exercise heart rate as well. If you’re taking any prescription or over-the-counter drug, you should know whether it affects the heart rate. Some drugs raise the heart rate. These include thyroid medication, Ritalin and other amphetamines, and even caffeine, which is found in certain cold remedies, pain relievers, and, of course, coffee, tea, and some sodas. These drugs will often cause higher exercise heart rates, forcing you to slow down to maintain your maximum aerobic heart rate. This means that by following your heart rate you may have to reduce your exercise intensity.
NOTE: Before beginning any training regimen, make sure it is medically safe for you to do so. If you have any injury, disease, disability or other concerns about starting an exercise program, consult your healthcare provider first.
Questions always welcomed! And I’m always happy to take you through a conditioning workout!
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