A normal resting heart rate (RHR) – the number of beats per minute (bpm) while at rest – ranges from 60–100bpm. Highly trained athletes may have RHRs far lower, however, sometimes dipping below 40bpm.
So, does RHR reflect fitness levels? The short answer is yes, but it’s not the whole story. Research suggests that there is a correlation. Lower RHR is often associated with better cardiovascular fitness because regular physical activity strengthens the heart muscle, allowing it to pump blood more efficiently. As a result, the heart doesn’t have to work as hard during periods of rest, leading to a lower RHR.
Several studies have found an association between lower RHR and higher levels of cardiorespiratory fitness, as measured by maximal oxygen uptake (VO 2 max) during exercise testing. For example, a 2018 review found that exercise, especially endurance training and yoga, decreases RHR and this effect may contribute to a reduction in all-cause mortality. A meta-analysis on RHR and fitness, published in the Journal of the American Heart Association in 2016, pooled data from 46 studies involving over 1.2 million participants. It found a significant association between higher RHR and increased risk of all-cause mortality and cardiovascular mortality.