Did you know that the max heart rates of trained athletes are lower than in age- and gender-matched, sedentary people? We just can’t get our heart rates as high (Whyte GP, George K, Shaver R, et al. 2008. Training induced changes in maximum heart rate. Int J Sports Med 29(2):129-33). Seems contrary to logic, huh? Science hasn’t been able to unequivocally determine the reason why, but it probably has to do with how much more efficient an athlete’s heart is when compared to the hearts of sedentary folks. We get more blood pumped per beat so need fewer beats to get the job done. In fact, the best way to get your max heart rate higher, a goal I sometimes hear athletes suggest, is to lose fitness. That will do the trick. In other words, a high max HR is not a good predictor of how highly fit you are. It’s just the opposite. You want a low HR. This is especially true during aerobic exercise. The lower your HR is relative to your power or pace, the more aerobically fit you are.Back to the aging series tomorrow.