Why Your Heart Rate Decreases While You Sleep
Investigate the sleep-heart rate connection for helpful insights into your cardiac health and overall wellbeing.
The sleep-heart rate connection
During sleep, your body undergoes numerous changes as it rests and repairs. As you transition from wakefulness to sleep, your body's metabolic rate decreases, along with your energy expenditure. As a result, your heart doesn’t need to work as hard to meet your body’s demands and it slows down.
The autonomic nervous system
To understand this phenomenon more deeply, let's consider the autonomic nervous system, which controls involuntary bodily functions like heart rate. This system has two branches: the sympathetic and parasympathetic nervous systems. The sympathetic system is responsible for the "fight or flight" response, increasing heart rate during moments of stress or physical activity. In contrast, the parasympathetic system, known for being the "rest and digest" system, is responsible for conserving energy and regulating bodily functions.
The parasympathetic system dominates during periods of relaxation, such as when you're winding down, resting, or, most notably, during sleep. Its role is to promote the body's recovery and conserve energy. Activation of the parasympathetic system results in a slowdown of physiological functions, like your heart rate, to aid in digestion, healing, and repair.
Circadian rhythms
Another contributing factor to the decrease in heart rate during sleep is your body's natural circadian rhythms. These internal biological clocks regulate various bodily functions throughout the day, including heart rate. As night falls and your body prepares for sleep, your circadian rhythms signal a slowdown in your heart rate as part of the overall relaxation process.
The health implications
Understanding why your heart rate decreases during sleep is more than just a scientific curiosity. It can offer valuable insights into your overall health. A consistently lower resting heart rate is often associated with a better heart rate dip, meaning that you’re achieving a higher quality of sleep. It's a positive sign that your body is well-rested and adequately recovered. To learn more about your heart rate dip, read our article The Basics: Heart Rate Dip.
