Fit Minute | How Much Sleep Do You Need?

puppy and kittens sleeping togetherIs there a magic number of hours you should sleep? According to studies on sleep and mortality, insufficient sleep can shorten your life. Sleeping plays an important role in:

  • Healing and repairing blood vessels
  • Maintaining a healthy balance of hormones that control your appetite
  • Controlling blood glucose (sugar)
  • Repairing cells and tissues, thus boosting bone/muscle mass
  • Defending against foreign or harmful substances

You can experience the following immediate and long-term health effects when you don’t get enough sleep:

  • Diminished cognitive function
  • Increased levels of cortisol (stress hormone) which cause the following:
    1. Increased appetite / See video: Undersleeping and Overeating
    2. Increased body weight
    3. Increased belly fat / See video: Beer Belly Anatomy 101
    4. Increased risk for type 2 diabetes
    5. Increased chronic low-level inflammation which leads to chronic disease (such as, coronary artery disease, dementia, and stroke)
    6. Increased blood pressure

If Seven is Good, Is Eight Better?   

Many people believe that they need at least eight hours of sleep a night for good health. But a study* reveals that sleeping seven (7) hours per night had the best survival rates. In fact, mortality hazard significantly increased when sleeping:

  • ≥8 hrs. (When sleeping >8.5 hrs., health risk exceeded 15%.)
  • ≤6 hrs. (When sleeping <4.5 hrs., health risk exceeded 15%.)

Causes of death associated with sleep duration include:

  1. Heart disease
  2. ‘Other causes’
  3. Cancer
  4. Stroke (Deaths from stroke were highest in men and women who slept 8, 9, and ≥10 hrs.)
  5. Breast cancer
  6. Colon cancer

Bottom line: Those who reported they slept 6.5 to 7.4 hours had a lower mortality rate than those with shorter or longer sleep.

*Six-year study by American Cancer Society; 1.1 million men/women ages 30-50 to >70 years. Published JAMA Psychiatry article: Mortality Associated With Sleep Duration and Insomnia, 2002.