Sleep deprivation has a similar impact on the body to the ageing process and may increase the severity of age-related chronic disorders such as heart disease and diabetes, researchers have found.
These days, the average number of hours people spend asleep per night in more developed countries has decreased from nine hours to seven-and-a-half hours. The change has been made to accommodate increased demands of work and more leisure activities.
A team from the US Department of Medicine in Chicago, investigated whether lack of sleep can alter metabolic and hormonal functions. Professor Eve Willis, who led the study, said: "We found that the metabolic and endocrine hormonal changes resulting from a signficant slep debt mimic many of the hallmarks of ageing.''
The Chicago team tested the effect of different amounts of sleep on 14 young men. The participants were allowed eight hours per night for the first three nights of the study. On the following six nights, the participants were restricted to four hours' sleep a night. Finally, they were allowed 12 hours' sleep a night for the concluding seven nights of the study.
The investigators took measurements during the day of glucose tolerance, cortisol concentrations (a hormone that helps to regulate blood sugar concentrations), heart rate, sleepiness, and the impact on the production of various hormones. Following the period of sleep deprivation, the researchers found subjects had higher levels of glucose and cortisol in their blood.
Sleep deprivation also led to an increase in the activity of the sympathetic nervous system, which controls many of the body's "involuntary" functions.Dr McKinley, a consultant respiratory physician at Edinburgh Royal Infirmary, said the research showed sleep deprivation provoked a typical stress response in the body, characterised by raised cortisol and glucose levels.
Dr McKinley said the amount of sleep people required varied between individuals. The important thing was to feel thoroughly rested after waking up.In many cases the quality of sleep was more important that the quantity, he said.
He said persistently high levels of glucose increased the risk of developing diabetes, heart disease and strokes