The TL;DR
Resting Heart Rate (RHR) is the number of times your heart beats per minute while you are completely at rest. It is a direct proxy for the efficiency of your heart muscle and the dominance of your parasympathetic nervous system (rest-and-digest). In the context of longevity, lower is almost always better.
Accessibility Level
Level 1 (Foundation): Can be measured for free (fingers on wrist) or with any basic wearable.
The Physiology of RHR
Stroke Volume & Efficiency
Why do athletes have low heart rates? Because their hearts are strong.
- Stroke Volume: The amount of blood ejected with each beat. A stronger heart pushes more blood per beat, so it doesn’t need to beat as often to supply the body with oxygen.
- High RHR: Indicates a smaller, weaker heart that must work frantically to keep up with baseline demands.
Autonomic Balance
The heart’s pacemaker (SA node) is controlled by two nerves:
- Vagus Nerve (Brake): Slows the heart down (Parasympathetic).
- Sympathetic Nerves (Gas): Speed the heart up (Sympathetic).
A low RHR indicates high “Vagal Tone”—meaning your braking system is strong and your stress system is calm.
The Longevity Connection
The “Finite Beats” Theory
While not literally true that you have a “quota” of beats, there is a fierce correlation across the animal kingdom: fast heart rates = short lives (mice), slow heart rates = long lives (whales).
In humans, epidemiological data is clear:
- RHR > 80 bpm: Significantly higher risk of all-cause mortality.
- RHR < 50 bpm: Associated with high fitness and longevity (barring pathology).
Measurement & Optimization
For detailed protocols on how to track and improve your RHR, see the measurement guide:
Go to: Heart Rate Monitoring Guide
References
Zhang, D., et al. (2016). Resting heart rate and all-cause and cardiovascular mortality in the general population: a meta-analysis. CMAJ.
Jensen, M. T., et al. (2013). Elevated resting heart rate, physical fitness and all-cause mortality: a 16-year follow-up in the Copenhagen Male Study. Heart.