Steve, what is your opinion on using the standard formula for determining your maximal heart rate? I am 49 years old and, although not in great shape, I can keep my heart rate around 150 beats per minute (bpm) for an hour without calling for the defibrillator. Actually, I could push it much harder but was told that a constant level would be the best way to achieve greater aerobic fitness (I was warned to stay away from the 150-170 bpm range, not sure why). My heart rate monitor read over 170-180 range last season while practicing. What do you think?
Christopher
The maximal heart rate (MHR) formula to which you are referring (220-age) has been around since the 1970’s and, even though it is based rather arbitrarily on only 10 studies whose subjects had cardiovascular disease, smoked and/or were taking cardiac medications, it has served as an accurate enough predictor across a broad range of populations. Even so, there have been some attempts over the years to establish a more appropriate equation for healthy individuals.
One recent meta-analysis of over 350 studies concluded that the traditional equation overestimates MHR in young adults up to age 40 and then increasingly underestimates MHR beyond that. The regression equation that they came up with was 207 – (0.7 x age). If we compare the two formulas we can indeed see that the traditional formula overestimates the maximal heart rate of an 18 year old by more than 7 beats per minute. For you, at age 49, it underestimates your maximal heart rate by less than 2 beats per minute.
220 – 18 = 202
207 – (0.7 x 18) = 194.4
220 – 49 = 171
207 – (0.7 x 49) = 172.7
Understand that, no matter what formula you use, individual variability can be quite high.
All that said, I don’t concern myself with heart rate when riding or training as it doesn’t provide any meaningful information to the motocross athlete. Additionally, maintaining a relatively lower heart rate for longer periods is not the only way to achieve aerobic fitness nor is it the best for motocross. But, those are topics for other posts.
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