If you’ve been around a gym or know people who work out, then you’ve probably heard the acronym HIIT, which stands for High Intensity Interval Training. Various programs, including CrossFit, offer this type of training, which implements functional movements at a high intensity.
High Intensity Interval Training methods can be applied during running or to various exercises, such as squatting or kettlebell swings. This type of training is considered to be more effective than your standard “cardio,” because the intensity is at a level in which you are able to increase both your aerobic (with oxygen) and anaerobic (without oxygen) endurance while burning off that excess fat. The anaerobic system provides energy for short bouts of exercise while the aerobic system is involved with prolonged exercise. (This is another subject in itself, which I will discuss in the future.)
If you’re not experienced with the way your body feels during exercise, checking your heart rate is the best way to measure intensity, in my opinion.
If your heart rate doesn’t increase much during the higher intensity segments of training, then you’re most likely not training at a high intensity, but more along the lines of a moderate level. If your body isn’t familiar with high intensity movements, then I would suggest staying at a level where you’re capable of performing comfortably, as well as checking with your physician before starting.
I feel that with any type of program, it’s important to know your heart rate throughout training. Heart rate monitors make this an easy task, but you also can do this by hand. Various factors, according to the Mayo Clinic, can affect your heart rate, including activity and fitness level; air temperature; body position (standing or lying down); emotions; body size; and possibly some medications.
To get a good idea of where you are, you have to first find your resting heart rate (RHR). While resting, find your pulse either in your neck (carotid) or your wrist (radial). When you feel your pulse, count the number of beats in 15 seconds. Multiply this number by four to calculate your beats per minute (bpm). Normal resting heart rate for adults ranges from 60 bpm to 100 bpm. Before starting your training session, find your target zone with the Karvonen formula.
You already know how to find your own resting heart rate from above. To find your maximum heart rate, subtract your age from 220. Once you have your maximum and resting heart rates, plug them in to the formula below and find your heart rate reserve. As far as intensity level goes, we’ll have a low end of 50 percent to a high end of 85 percent. Plug these into the percent intensity by placing a decimal — .50 and .85.
(Heart Rate Reserve × Percent Intensity) + Resting Heart Rate = Target Heart Rate
220 – Age = Maximum Heart Rate
Maximum Heart Rate – Resting Heart Rate = Heart Rate Reserve
(Heart Rate Reserve)(.50 or .85) + Resting Heart Rate = Target Heart Rate
Tyler Morrison, BS, Certified Fitness Trainer, and Lifestyle & Weight Management Specialist at Urban Health & Fitness, Total Fitness, and Crossfit Galveston.