Author: Myron Yau, Nutritionist at HKBioTek
According to an epidemiological study in USA, the obese population in USA increased dramatically from 1991 to 2001, while another study indicated that the number of Americans sleeping less than 6 hours in average increased significantly. This revealed the association between sleep deprivation and obesity or overweight.
Acute short term sleep loss and prolonged sleep deprivation have similar instant outcomes. Firstly, the release of a hunger hormone (Gherlin) in human body increases while that of a satiety hormone (Leptin) decreases significantly as soon as two nights of sleep loss, sensing our brain to enhance food intake. When energy intake is larger than energy expenditure, the positive energy balance leads to overweight or even obesity. Secondly, more stress hormone (Cortisol) will be secreted, leading to accumulation of abdominal fat. Thirdly, reduced production of insulin and glucose intolerance will also be seen when sleep deprived. The last two factors in turn increase the risk of acquiring type II diabetes mellitus. Yet a number of other physiological changes will also be caused if you do not get enough sleep.
A complete sleep will allow you to be recovered from the physiological changes brought by acute short term sleep. However, that of long-term sleep deprivation cannot be reversed or compensated by sleeping.
But please do not get us wrong. We are not telling you to sleep as much as possible to save yourself from being overweight. In general, an optimal sleep is 8 hours for adult adults and 10 hours for children. Besides sleep duration, sleep quality also plays a role. A research study indicated that discontinuous sleep brings similar physiological changes as that of sleep deprivation.
All in all, sufficient sleeping duration together with good sleeping quality, diet control and regular exercise are good means to tackle and prevent obesity.