Dad Fitness- How Accurate Is Your Training Heart Rate?


Arguably, the most common measure used to control exercise intensity among competitive dads is heart rate.

The development of small, affordable, portable telemetry units has resulted in their widespread use among dad fitness enthusiast. Furthermore, they are used not only to gauge exercise training intensity but also to regulate race pace and recovery. The question is how accurate this data is in terms of monitoring exercise intensity. The accuracy of the monitor is not in question, for it is high, but are the calculations accurate enough to make the numbers meaningful?

Few will argue that the quality of an exercise session is, for the most part, determined by intensity. In the field, on the track, or in the water, heart rate monitoring allows for more accurate regulation of exercise intensity when compared to traditional measures of perceived intensity. The key to intensity regulation is based on target heart rate calculation to determine exercise intensity at a relative percent of maximum heart rate (MHR). There are several methods of calculating this zone, all yielding varying responses.

220-age=MHR   (Equation 1)

210-0.5age=MHR (Equation 2)

MHR-resting heart rate (RHR) = heart rate reserve (HRR) (Karvonen Fomula, Eqaution 3)

The determining factor in all calculations is age, and it is well established that MHR declines with increasing age and that age alone is the sole determining factor. However, like most physiological variables, there is a high degree of interindividual variation. Consider the following numbers based on calculating 70-80% training zones for a 40-year-old (RHR 65 bpm) using each method:

MHR= 220-age =180 bpm; 70-80% training zone = 126-144 bpm (using equation 1)

MHR= 210 – 0.5age = 190 bpm; 70-80% training zone = 133-152 bpm (using equation 2)

HRR = MHR – RHR = 115 bpm;

70-80% training zone = 145-157 bpm (using equation 3)

Using three simple figures alone, we have up to a 14% variation in the low end exercise heart rate. For serious athletes, this is a huge difference and will yield considerable variations in training outcomes. This problem may be compounded when we are actually unsure if any of these numbers are correct.

The major limitation in all calculations is the absence of a true measure of MHR. This is really what all athletes need individually and should determine periodically during their training phases. This does not need sophisticated equipment but merely a progressive protocol that incrementally will exhaust the athlete in 12-15 minutes. You’ll need a heart rate monitor, and then simply record the maximum heart rate achieved during the session (typically it will occur as the athlete is exhausted). This number will yield much greater accuracy than a traditional prediction equation. So how much more accurate will this number be?

The mode of exercise used will yield varying responses. Running will yield a higher MHR than cycling. You should choose your preferred mode of exercise to determine your true MHR. Therefore, as a rower, you should perform this trial on the ergometer or on the water. Each athlete should have his/her own individually measure MHR and remember his/her target zone. Data from a review article illustrates this variation in calculated heart rates. They first show the variation in MHR as a function of mode and also show that running produced MHR numbers close to the 220-age equation. The numbers generated on the treadmill were significantly different from all other calculations. The numbers generated during cycling were significantly less than predicted (on average, 18bpm) and varied from -35 bpm to +16 bpm. Cycling data was, on average, 96% of treadmill data.

Keep these equations handy, as well as purchase your own heart rate monitor on the links below.

Places to review and purchase a monitor: