After a review of the research, it turns out the common formulas used to determine Maximum Heart Rate (MHR) and Target Heart Rates (THR) may not have as much value as once thought. MHR and THR are commonly determined by using the Karvonen Formula which is determined by subtracting your age from the number 220. This number is then used to determine appropriate training ranges (THR) for your heart rate during cardio, by subtracting your resting heart rate from 60-80% of your individual max (MHR).
First off, when referring to Max Heart Rate- The definition of this term is widely misunderstood. It refers to the level at which the heart rate will not continue to elevate, regardless of increase in work performance or training adaptations. This does NOT mean that if your heart rate goes above this level, you are at risk for heart failure, myocardial infarction, etc. Kind of like if your car only has a top speed of 120mph, it won’t go any faster no matter how much harder you stomp on the accelerator…but the ‘top speed’ of the car doesn’t signify the speed at which the car will blow up!
Karvonen, contacted in August of 2000, indicated that he never published the original research of this formula, and recommended researching the work of Dr. Astrand for original research. Astrand then stated that he did not publish any data to derive this formula (1). Astrand’s data was contradictory to the “Karvonen” formula, in that he noted a non-linear decrease in HRmax, as opposed to the 1 beat per year data used for the formula, that Karvonen now denies he even came up with. Original data appears to come from Fox et al., who himself even stated that, “…no single line will adequately represent the data on the apparent decline of maximal heart rate with age…” (2). ASEP researchers state, “Currently, there is no acceptable method to estimate MHR” (3). It turns out, that using the Karvonen Formula one could end up with an error of 15-30bpm for target heart rates.
These formulas are also used to determine VO2max, a method of determining a person’s cardiovascular fitness. ASEP Physiologists agree that if a VO2max concludes more than a 3bpm discrepancy, “…there is no justification for using methods of VO2max estimation that rely on the HRmax prediction formulae” (3). Specific populations need to be taken into account when determining acceptable heart rates (age, gender, training experience, medical conditions, caffeine intake, etc.), and using a standardized formula is irresponsible for cardio workouts.
So what do we do now? Those that have trained under my supervision know I’ve never recommended using heart rate at all to determine workout efficacy or safety. A much simpler method called the Rate of Perceived Exertion (RPE) yields far better results in your cardio workouts, and accounts for all specific population requirements. Use a numbered scale of 6-10, with 6 being a slow walk, and 10 being an all out exertion (this can range from a fast walk up to a full sprint, depending on your fitness level). Choose your RPE and stick to it. If you’re interval training, try to perform bursts at a 9-10, and recoveries at a 7 or 8. If you’re performing a steady state run/bike/elliptical, just stick with a moderate 7-8. Simple and effective. And ‘fat loss zones’ at certain heart rates are extremely outdated, as they don’t take into account EPOC, or the amount of calories burned post exercise in the 6 or so hours following.
1. Wandewalle GP and Havette P. Heart rate, maximal heart rate and pedal rate. J Sports Med 1987;27:205-210.
2. Fox III, S.M. Naughton, J.P. and Haskell, W.L. Physical activity and the prevention of coronary heart disease. Ann Clin Res 1971;3:404-432.
3. ROBERT A. ROBERGS AND ROBERTO LANDWEHR, THE SURPRISING HISTORY OF THE “HRmax=220-age” EQUATION. ISSN 1097-9751, Volume 5 Number 2 May 2002, Official Journal of The American Society of Exercise Physiologists (ASEP).