Healthful sleep has been empirically proven to be the single most important factor in predicting longevity, more influential than diet, exercise, or heredity. And yet we are a sleep-sick society, ignorant of the facts of sleep—and the price of sleep deprivation. We have paid for ignoring sleep: an epidemic of heart disease, 33% of traffic-fatigue-related accidents, and immeasurable mental and psychological disadvantages.
Impact of sleep debt on metabolic and endocrine function ( Abstract from The Lancet)
Chronic sleep debt is becoming increasingly common and affects millions of people in more-developed countries. Sleep debt is currently believed to have no adverse effect on health. We investigated the effect of sleep debt on metabolic and endocrine functions.
We assessed carbohydrate metabolism, thyrotropic function, activity of the hypothalamo-pituitary-adrenal axis, and sympathovagal balance in 11 young men after time in bed had been restricted to 4 h per night for 6 nights. We compared the sleep-debt condition with measurements taken at the end of a sleep-recovery period when participants were allowed 12 h in bed per night for 6 nights.
Glucose tolerance was lower in the sleep-debt condition than in the fully rested condition (p<0.02), as were thyrotropin concentrations (p<0.01). Evening cortisol concentrations were raised (p=0.0001) and activity of the sympathetic nervous system was increased in the sleep-debt condition (p<0.02).
Sleep debt has a harmful impact on carbohydrate metabolism and endocrine function. The effects are similar to those seen in normal ageing and, therefore, sleep debt may increase the severity of age-related chronic disorders.
How many hours sleep do we need
We need generally between 8-9hours good sleep for maintain a healthy system. But it can be vary for individuals.