Interval Training 101
Sometimes I get bored with endurance training and feel like my body has hit a plateau. To keep things interesting and to challenge myself, I implement interval training into my weekly workout routine about 1-2 times per week. Someone recently asked me what the benefits of interval training are and while I could generalize the reasons off the top of my head, I decided to delve into the specific reasons why interval trainings is so effective and its benefits and drawbacks.
I’ll start with the negatives: it’s hard. Also one of the reasons it is so great and effective. Obviously more intense exercise can be tough on your joints and, if you’re not an already active or fit person to begin with, you could risk injury if you go too hard too soon. Poor form could also lead to injuries so it is important to focus on proper form and technique and to ease into it if you’re new or if your base fitness isn’t quite there. The best workout is the one you’ll actually do so if you’ve tried interval training and hate it, that’s fine. Stick with what works for you. If you’re getting bored with the usual routine and feel like you have hit a wall though, maybe interval training is something for you to try - I love it and the feeling of exhaustion afterwards is my kryptonite. Maybe it will be yours too.
It's a love-hate relationship.
Onto the positives! Interval training is ideal for busy people. Because of its intense nature, interval training isn’t meant to last any longer than 30 minutes or so. It is therefore less time consuming than a [boring] steady-paced (and what seems like hours long) workout most of us think we need to do in order to get a "good" workout. True, the "I have to do cardio at the same pace for an extended period of time" mindset is sometimes a beneficial workout, but in reality, most people aren’t motivated to workout in the first place and the thought of spending hours at the gym makes some cringe (not me, but that might be you). Got 30 minutes or less? I’m sure you do! So what other health benefits are there you ask? Let’s talk about interval training and all it's glory.
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Don'tcha'?
Interval training can take on various forms, some of which I am sure you’re familiar with: high intensity interval training (HIIT), high-intensity intermittent exercise (HIIE), sprint interval training (SIT), TABATA, lifting AMRAP, cycling intervals/jumps, Insanity, crossfit, etc. One of the main reasons why fitness gurus Sean T., Greg Glassman and Izumi Tabata's fitness empires have exploded with success is because of their unique [yet simple] approach to working out: all of their workouts focus on interval training. Get that heart rate up (skyrocketing) then bring it back down (short rests). Their workouts are intense (done in short bursts), not very time consuming, and most importantly, they get results.
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Don't like body weight exercises or lifting? Get your sprint on.
According to the American College of Sports Medicine, HIIT training has been shown to improve:
aerobic and anaerobic fitness
blood pressure
cardiovascular health
insulin sensitivity (which helps the exercising muscles more readily use glucose for fuel to make energy)
cholesterol profiles
abdominal fat and body weight while maintaining muscle mass
For years, we were told that if we wanted to properly build our base fitness, we needed to spend hours at a steady, low-intensity logging miles and lifting weights to strengthen our aerobic systems, so they could eventually handle harder, more intense training. Well, this method works great if it’s your job to get up and run, lift, or ride your bike for four to six hours a day, but for the rest of us without that luxury, a schedule-friendly method of HIIT training presents a practical way to build endurance (and muscles) on a time budget.
Less time, more cals burned.
Interval training is so fantastic because it can burn more or just as many calories compared to traditional steady-paced lower-intensity workouts for an extended period of time. The most amazing part is the post-exercise period called "EPOC," excess postexercise oxygen consumption. Generally, this is a two hour period after a workout where the body restores itself to pre-exercise levels, utilizing tons of energy in the process. In comparison to a "normal" steady-paced low-intensity workout, research suggests that the interval EPOC period adds 6 to 15% more calories to the overall workout energy expenditure. So what exactly does that mean other than the fact your body burns more calories post sweat-sesh and why should you care?
Ever heard of the VO2 max? VO2 max is a measure of the maximum volume of oxygen that you can use during exercise (the initials simply stand for volume of oxygen). It is measured in milliliters per kilogram of body weight per minute (ml/kg/min). When you increase your effort during exercise, it increases the amount of oxygen you consume to produce energy (and hence the rate at which you exhale carbon dioxide) increases. It’s when you’re sucking wind. That doesn’t necessarily mean that you are out of shape (obviously - you're just out of breath). Basically, your body has a maximum level of oxygen consumption, beyond which any increase in exercise intensity will not lead to further increases in oxygen consumption - you hit your peak in other words. This level of oxygen consumption is called the VO2 max. Some experts believe that VO2 max is a key physiological determinant of an athlete’s performance, and that it is an important objective of a training program to improve it. Other sports scientists persuasively argue that the limits to an athlete’s running performance are determined by a range of factors – such as genetics, adaptation of muscles, running efficiency, metabolism – and that VO2 max is simply a measure of the oxygen that the athlete consumes at the maximum level of energy output. On this view, VO2 max is not the critical factor which determines maximum performance, but is rather a consequence of a combination of other limiting factors. Whichever way you look at it, there is a measurable level of exercise intensity of a person’s consumption of oxygen when it reaches a plateau and does not increase further. Some research suggests that a person’s VO2 max can be increased by interval training anywhere between 5 and 20% (with some increases of up to 60%)! Studies have shown that for a small portion of the population, interval training seems to make little difference when it comes to increasing the VO2 max. Factors such as training intensity, genetics, base fitness level, metabolism, etc. could provide explanations as to why that is.
The take-away is that the majority of the population can benefit from interval training, a less time consuming workout method with a plethora of health benefits including increases in aerobic and anaerobic fitness levels, blood pressure, cardiovascular health, insulin sensitivity, cholesterol profiles, decreasing abdominal fat and body weight while maintaining muscle mass, and an increase in your VO2 max. There are tons of different kinds of interval training so you never have to do the same workout twice if you don't want to. If you're someone who gets bored easily then this might be a great method to try. So if you’re bored with your usual routine or feel like your fitness has plateaued, try it out!
Roll with the punches.
Keep in mind that interval training, though beneficial, is also stressful on your body. It's hard and obviously not for everyone. It is therefore essential that if you train like this, you not only include easy days and rest days into your weekly training plan, but also that you eat a balanced diet, get adequate sleep, and be mindful of your general recovery. Be realistic about how active and/or fit you are before jumping into interval training. Doing so will only risk injury and derail your long-term fitness goals. Make sure you give your body the rest it needs so that you don't end up with high levels of stress hormones and inflammation that can do real damage over time. And make sure you have good form, PLEASE. Try it out but be smart about it. Not everyone is Michelle Akers (go look her up - she was one of the toughest and most athletic professional athletes of all time), but we can certainly strive to be more like her.
Next weekend I will post a series of different interval workouts for you to try, saving you even more time! All you have to do is get out there and do it. Have a happy weekend, friends!
