Sleep is an important modulator of neuroendocrine function and glucose metabolism. It has been reported that the worldwide prevalence of obesity has doubled since 1980, with women more likely to be obese than men. This obesity epidemic has been paralleled by a trend of increasing prevalence of sleep loss in both children and adults in the modern society. We are sleeping a lot less than we were a few decades ago and are paying the price for it. Significant amount scientific evidence has indicated that poor sleep quality and sleep loss can cause endocrine alterations, including decreased insulin tolerance and sensitivity, increased level of cortisol in the body in evenings, increased level of ghrelin, decreased level of leptin, and increased hunger and appetite. There is a direct association between increased BMI and sleep loss. Children and adults who are short sleepers are at a higher risk for weight gain and obesity. In addition, the dysregulation of the neuroendocrine control of appetite and the alteration of glucose tolerance in people who are not getting enough sleep exposed them to an increased risk of getting diabetes later in life.
So, how much sleep is enough? Well, it really depends on the individual and your age group. One may feel properly rested after 6 and half hours of sleep while others may need 9 hours of sleep to feel rejuvenated. The average basal sleep need for a healthy adult is around 7-8 hours per night. This is discounting all the sleep debt that one accumulates due to previous sleep loss, which may make you feel tired even after a few nights of good sleep unless the debt is paid.
Many of us work very hard to keep our weights down but sometimes we forgot that basic routines in life such as sleep could have a far greater impact on our body and health than the extra 2km you run on the treadmill the other day. Getting enough sleep is probably the easiest, cheapest and most productive way of setting yourself up a good foundation to a healthy and lean life.