No, that is not a typo in the headline. HIIT stands for high intensity interval training, and if you’re not incorporating it into your workout, you are missing a great calorie burner and time saver. How could it possibly get any better than that? Workout for less time and burn more calories? Score!
Oh yeah, there’s one catch: you have to work HARD. Like this dude.
You don’t have to look like this guy to do HIIT–it’s not just for physical specimens–but you should take a cue from his expression. He is pushing his limit for sure. But before you get scared away, understand the key to that sentence is “his limit.” Here’s what I mean: HIIT uses short bouts of maximum intensity exercise paired with light to moderate intervals of recovery. But depending on age and fitness level, your body’s version of maximum intensity could be much different from sprinter man there.
HIIT is doable for most healthy individuals who have been exercising consistently at a moderate intensity. If you are brand new to exercise, or if you have limitations due to injury or disease, start building a base level of fitness. Always check with your doctor before you start any new exercise program, particularly one that includes HIIT.
Why do HIIT?
Generally, we exercise at 60–85 percent of our maximum heart rate, for 30 minutes or more. This stresses the aerobic system, and is a low to moderate level of intensity that can generally be maintained for extended periods of time. Once we push past the upper range of the aerobic system, the body calls on the anaerobic system to delivery energy to muscles. It’s impossible to maintain this level of effort for long because the body can no longer keep up with energy demands. Soon the body must slow to replenish fuel for the anaerobic system. So why does this matter?
- alternating between maximum and moderate intensity allows both the anaerobic and aerobic systems to reap benefits, leading to improvements in your overall fitness level
- higher intensity exercise burns more calories in a shorter amount of time through a phenomenon called EPOC, or excess post oxygen consumption. The body has to work harder to recover from such an intense session, meaning your rate of metabolism can stay elevated for up to 24 hours post-workout
- studies indicate HIIT seems to preserve muscle tissue that is often lost during longer duration aerobic exercise
- HIIT relieves stress, shows you what you are made of and is a great excuse to make funny faces while you exercise!
How to do HIIT
While elite athletes can often sustain maximum intensity for up to three or four minutes, most people poop out before that. Start with 20–60 seconds all-out effort (over 85 percent of max), and 60–120 seconds of recovery (about 70 percent of max).
Your body will send you cues if you need to adjust your intervals. A burning sensation in your muscles tells you you’ve reached your upper limit for that interval. If your heart rate dips lower than about 70 percent of your max, you are taking too much recovery. If after 60–120 seconds your heart rate is still very elevated, take more time to bring it down and modify your work and/or recovery intervals.
There are a couple of ways to gauge your intensity when doing HIIT workouts. You can use a heart rate monitor (more on those here, and here), or you can use an RPE scale. RPE stands for rate of perceived exertion, and it’s a simple system for judging your workout intensity. On a scale of 6–20, with 6 being the effort it takes to sit in a chair, and 20 being the hardest work you could imagine, rate your level of exertion. RPE correlates with heart rate (6 is 60 bpm and 20 is 200 bpm), so whether you are using a monitor, or RPE, your work phase should be over 85 percent of your max. Use this tool to calculate different ranges.
If you are able to maintain 30 + minutes of aerobic exercise, aim for a 20 minute HIIT workout. Make sure to do an adequate warm-up of at least 5 minutes, and cool down at the end of your workout. Listen to your body! This is hard work people, so if you experience pain, light-headedness or difficulty breathing (you know what I mean), slow down immediately.
While the treadmill might seem an obvious choice, many modes of cardiovascular exercise lend themselves to HIIT. Anywhere you can manipulate your intensity works for HIIT. Try the elliptical, bike or even outdoors. Pair up and race a partner, then recover together. You can even incorporate HIIT into your strength training workout, by doing cardio or body weight intervals (squat jumps, jumping jacks, mountain climbers) with slower sets of single muscle exercises (lateral raises, biceps curls, triceps extensions). Think boot camp
Never do HIIT two days in a row. Your body needs adequate recovery from this type of workout. Start with once or twice a week, always alternating with days of low or moderate intensity exercise, strength training and flexibility training.
I’m not saying it’s going to be easy, but if you’re looking to kick it up a notch, this is the way to do it. Enjoy!