With any exercise program, especially cardiovascular exercise, it is important to monitor your exercise intensity level to ascertain whether it is challenging enough to achieve your fitness goals. Exercise too hard and you risk injury, overtraining or sabotaging your efforts. Exercise at a less than optimal level and your body isn’t challenged and won’t bring about the desired changes. Some ways to gauge the intensity level of exercise include monitoring heart rate, rate of perceived exertion or a talk test.
It is recommended that your target heart rate when exercising should be between 60% – 80% of your maximum heart rate. There are several formulas available to determine your maximum heart rate. Many heart rate calculators can also be found online and will do the calculation for you. The most basic, yet archaic, way to determine your maximum heart rate is to take 220 less your age. The Karvonen Formula, however, is another heart rate calculation method available. It is similar to the original formula but also takes into consideration resting heart rate. The Karvonen formula better predicts your target heart rate.
Just recently, however, researchers at Northwestern Medicine in Chicago announced a new formula to calculate heart rate for women. The new formula has caused much controversy and debate and begs the question whether any of these formulas are reliable or accurate. Rather than get bogged down by the controversy and debate, it is helpful to remember that the formulas were initially created to be a gauge, and should be used as a general guideline.
If you want to determine your heart rate with accuracy, the best way would be to test it using maximal or sub-maximal stress tests. These tests however can be inconvenient and in some cases should only be performed under medical supervision, especially if you are new to exercise.
As with most other advice, you are your best advocate. Nobody knows you better than yourself. Formulas were created based on a control group of individuals that were meant to represent the greater population. However, no two individuals are alike; therefore it is always best to determine what works for you.