National Sleep Foundation

Chapter 1: Normal Sleep

The Physiology of Sleep – The Cardiovascular System

Blood pressure and heart rates both change during sleep. There are brief increases in the person’s blood pressure and heart rate during K-complexes, sleep arousals, and large body movements. In the few hours before a person wakes up, and as the person wakes up in the morning, there is an increase in both heart rate and blood pressure (this is why there is higher risk of having a heart attack in the early morning and soon after awakening). 1

Lack of sleep and disordered sleep are also associated with heart attacks and, possibly, stroke. Just one night of acute sleep loss (3.6 hours of sleep) resulted in increased blood pressure in otherwise healthy young men. One large study found that getting 5 or fewer hours of sleep per night was associated with a 45 percent increase in the risk of heart attack (the researchers controlled for age, weight, smoking, and snoring). Interestingly, higher risk was also found among those who slept for 9 or more hours per night.2

References

  1. Institute of Medicine (IOM) Committee on Sleep Medicine and Research, Colten HR and Altevogt BM (ed.), Sleep Disorders and Sleep Deprivation: An Unmet Public Health Problem, Washington, DC: National Academy of Sciences, 2006.
  2. Institute of Medicine (IOM) Committee on Sleep Medicine and Research, Colten HR and Altevogt BM (ed.), Sleep Disorders and Sleep Deprivation: An Unmet Public Health Problem, Washington, DC: National Academy of Sciences, 2006.