HIIT is one of the best methods of exercise to get a high-quality workout in a short period of time. HIIT is the practice of exercising at a high level of intensity followed by short amounts of rest. This type of workout stresses your body at a very high level and leads to strong adaptations from your body. Benefits — such as decreasing body fat percentage, increasing your VO2 max (the maximum rate of oxygen consumption your body can sustain), and decreasing your resting heart rate — are all achievable with HIIT training.
There are several key principles for making a workout a HIIT workout, and the following principles should be followed — as they allow you to effectively stress your body and increase your fitness level.
HIIT workouts are designed to be intense. When you do a HIIT workout, your expectation should be to exercise at 85% to 95% of your max intensity (or max heart rate). When your intensity is up this high, your heart, which is just a muscle, has to adapt much more than if you were on a slow, long run. This translates to your heart growing stronger and can lead to increases in your VO2 max.
HIIT workouts are designed to be short periods of intense exercise followed by longer periods of rest. Since you’re exercising at such high levels of intensity, you naturally can only keep it up for a very short period of time. On the rest side, you need to allow your body a chance to recover so your body is able to once again hit the 85% to 95% intensity needed. HIIT routines have very specific work-to-rest ratios to reap the benefits. 1:2 or 1:3 should be the ratios used in a workout. Common examples are as follows:
- 30 seconds of work/60 seconds of rest
- 30 seconds of work/90 seconds of rest
- 45 seconds of work/90 seconds of rest
The whole HIIT workout should not last longer than 15 to 30 minutes. Remember these workouts will be very hard, so if you’re able to exercise longer than 30 minutes in a HIIT format, you’re not at a high enough intensity.
Note: Lowering the amount of rest from a ratio of 1:2 or 1:3 turns the HIIT workout into an interval workout. Interval workouts typically lower the amount of rest allowed, changing the ratio to 1:1 or 2:1 (30 seconds on/30 seconds rest or 30 seconds on/15 seconds rest). These types of workouts are still beneficial but are different than HIIT workouts.
I’ve found HIIT training to be more effective the more muscle groups involved. When you use multiple muscle groups, your heart is working harder to pump oxygen to all areas of your body, leading to a growth of your heart’s VO2 max.
The beauty of HIIT is in the endless combinations of movements that can be done. If you love burpees but hate squats, you can do an amazing workout incorporating a ton of burpees.
HIIT workouts aren’t just bodyweight-focused. They can also have a cardio focus. Running, biking, rowing, and climbing the stairs are all great modalities for HIIT, as they are full-body movements.
Single movements like bicep curls should not be used in HIIT workouts. This type of movement doesn’t significantly elevate your heart rate — thus, fitness level — when compared to a compound movement like burpees. With this in mind, HIIT training should focus on movements involving multiple muscle groups or full-body cardio.
HIIT workout frequency
HIIT workouts shouldn’t be done every day; in fact, the American Council of Exercise advises doing HIIT twice a week when beginning this style of training. After several weeks of committing to this style of workouts, you can add a third day and keep a careful eye out for overtraining. You’re stressing your body at a very high level, and your muscles need time to recover. The American Council of Exercise recommends a 48- to 72-hour recovery period in between HIIT workouts. This time allows your muscles to recover from the microtrauma you put upon them and to be able to once again reach the 85% to 95% intensity level you need.