Exercise, Heart Rate Variability, and Longevity: The Cocoon Mystery?
Humans are increasingly approaching an era where cardiovascular health seems to be one of the major upper limits on achievable lifespan. An increasing body of scientific research and observational evidence indicates that resting heart rate (HR) is inversely related to the lifespan among homeothermic mammals and within individual species. Heart rate not only reflects the status of the cardiovascular system, but also serves as an indicator of cardiac autonomic nervous (sympathetic and parasympathetic) system activity and metabolic rate. There is a remarkable amount of variation in HR among species, it can be as low as 30-35 beats per minute (bpm) in large animals like whales and elephants, or as high as 600-700 bpm in mice (Figure 1). Mammals that have slower average HR tend to live much longer than those that have faster HR.1,2 Although some variability inevitably exists and is observed in human, estimations yield a mean value of around 1 x 109 (1 billion) heartbeats in a lifetime across almost all homeothermic mammals (Figure 2).
- Received March 28, 2014.
- Accepted April 1, 2014.