A group of young, healthy people agreed to sleep in the lab for four consecutive nights, getting eight and a half hours of rest per night. Their fat cells were monitored, as well as other metabolic indicators, and they were deemed to be functioning quite well. Some months later, the same group of young people returned to the lab for another four nights — this time getting only four and a half hours of rest per night.
Their fat cells were observed, and the results were remarkable. The cells did not respond as well to insulin stimulation.
Normally, fat is stored in specific cells to be used for energy during various activities such as walking. When fat cells stop responding properly to insulin, they travel around and end up in unhealthy places, such as the liver. Having a fatty liver sets up another round of metabolic effects, which spirals an individual into a chain of unhealthy metabolic events. So not getting enough sleep can make it much harder to lose weight, and can make a diabetic person less able to manage their condition.
Other studies have offered additional insight into why sleep deprivation is so unhealthy.
In a National Geographic article, a study was revealed in which sleep deprivation caused mental impairment equivalent to taking shots of liquor. And other studies have shown that sleep deprivation lowers response of the immune system.
In related news: Give a new parent a pat on the back today. That zombie-like, sleep-deprived person is on a downward spiral of metabolic, mental and immune dysfunction that will likely last for the next year. That zombie parent deserves a fresh cup of coffee … or maybe mandatory afternoon naptime at work.