High-intensity interval training, HIIT, is gaining in popularity. During this type of fitness, you do short bursts of physical activity at near maximum exertion, then rest by doing something much lower in intensity for a short period before doing another high-intensity burst. The activities and times for both activity and rest vary by program.
Estimated Maximum Heart Rate and HIIT
During the intense activity periods of an HIIT work-out, a person is generally meant to be between 80-90% of their estimated maximum heart rate. Rest periods bring the heart rate down to 40-50% of the estimated maximum heart rate (ACSM Information on High Intensity Interval Training, 2014).
Estimated maximum heart rate can be calculated by subtracting your age from 220. Therefore, a person who is 20 years old would have a maximum heart rate of 200 beats per minute. Then, multiply that number by .8 to get 80% estimated maximum heart rate, by .4 to get 40%, and so on.
Always check with your doctor before beginning any new exercise routine, including HIIT.
Why Should You Consider HIIT?
HIIT may help you improve your overall fitness level, lower your risk of heart disease, help you decrease your cholesterol, increase your insulin sensitivity, and decrease your stress. One great thing about HIIT is that it can be modified for each individual's situation, the exercise they like to do, any medical conditions they have, and how much time they have to devote to working out.
You can create a high intensity interval training workout from any type of exercise. For instance, you could do it with cycling, either inside or outside, swimming, walking, jogging, or a group exercise class. Simply do the activity more strenuously to hit your target heart rate for a period of time and then lower your effort to bring your heart rate down for a time, repeating throughout the entire workout.
You may stop to take your pulse as you're working out, but it might help you to have a wearable heart rate monitor instead. Then you don't have to stop your workout to check that you're in the proper zone. We like the Garmin Vivosmart HR, which is water resistant and can be worn while swimming and showering.
The Two Main Time Frequencies Used in HIIT
There are several ways that HIIT can be done, but most programs use one of these two methods:
- High intensity exercise is done for a period of time between 30 seconds and 8 minutes, and then a period of lower intensity exercise is done for an equal amount of time, repeating until the workout is done, usually between 10 and 60 minutes total.
- A sprint of high intensity exercise is done at as high of an output as can be managed for 30 seconds; then lower intensity exercise is done for 3-4 minutes, alternating for 4-6 sets.
Again, which type of HIIT you choose and how intensely you perform it should be dictated by your current fitness level and general medical health. Consult with your doctor to determine what's right for you.
Concerns Related to HIIT
If you are just beginning with exercise and have been sedentary, have a history of heart disease or it is prevalent in your family, or if you smoke, are obese, have joint problems, or have diabetes, you should speak with your doctor before considering HIIT.
In general, it's a good idea to establish a base level of fitness before engaging in HIIT. Doing an aerobic activity several times a week for 30-60 minutes each for a few weeks prior to beginning an HIIT program can help reduce your risk of injury (ACSM Information on High Intensity Interval Training, 2014).
Always check with your doctor before beginning any new exercise routine, including HIIT.
Similarly, you should be careful when beginning an HIIT program in something that you aren't already proficient in doing because your risk of injury due to improper form will be higher when you are exercising at high intensity. If you are starting something new, it is a good idea to master the technique of the exercise first before transferring it into a high-intensity interval training program.
HIIT work-outs are more taxing on your body than endurance exercises, so you shouldn't do them as often. When you are first starting out, consider doing HIIT once a week and gradually increase from there. Always listen to your body. Tired muscles can be good, but pain is not.
References
- ACSM Information on High Intensity Interval Training.(2014). Retrieved from American College of Sports Medicine.