Get Enough Sleep and Weight Loss Will Be Easier
A lack of sleep can have hefty consequences for your weight, according to research undertaken by Dr Siobhan Banks from the Centre for Sleep Research.
Dr Banks’ recent studies conducted at UniSA and in the United States have shown a link between lack of sleep and weight gain.
In her study in the US, one group of participants put on more than one kilogram of weight each in just five nights when they slept for only four hours per night. This contrasted with those in the control group who were allowed 10 hours’ sleep per night and did not gain any weight.
In another study conducted at UniSA’s City East campus, participants were also allowed only four hours’ sleep a night over five nights, but unlike the US study their food intake was closely monitored. This was so Dr Banks and colleague Amy Reynolds could ascertain how glucose metabolism changed with sleep restriction.
Dr Banks says this study found short-term sleep curtailment led to changes in glucose metabolism and adrenal reactivity – which when experienced repeatedly, could increase the risk for type-two diabetes.
“We based this study on a typical work week, but took the sleep amounts down to less than most people would typically get so we could see the response,” she says.
“With these participants we did measurements at baseline and then after the period of sleep restriction.
“We found that while fasting glucose wasn’t changed, the response to meals was dramatically affected by sleep restriction. The body didn’t appropriately respond to meals and this caused glucose to rise in the blood.
“Even though insulin increased, it wasn’t enough to deal with the increases in glucose, which stayed quite high.
“The longer you have higher levels of glucose in your blood and an increased insulin response you are at higher risk for developing insulin resistance, which has a number of associated metabolic problems.”
Dr Banks says other studies around the world have looked specifically at sleep and weight loss, comparing people getting five hours’ sleep a night to those getting eight hours’ sleep. With the same diet and exercise patterns, those getting eight hours’ sleep per night lost more weight.
“By sleeping well, your body is functioning properly, all the hormonal responses are working well and you are able to more effectively lose weight,” she says.
“Sleep restriction on the other hand seems to be a physiological stressor which throws out the hormonal balance.”
Dr Banks says in addition to the hormonal response in the body, the food choices people make when they are sleep-deprived also play a major part in weight gain.
“People do seem to eat the wrong foods when they are sleep-deprived and what we don’t know quite yet is whether that is a physiological kind of craving or is it psychologically driven,” she says.
“We’ve all had that feeling of wanting comfort food because we are tired and if you’re eating poor foods, your body is going to be dealing with more fat and carbohydrate, and you’re more likely to gain weight.
“In my US study where the food intake was not restricted, some of the participants just ate constantly and gained quite a lot of weight.
“In the study here at UniSA we were specifically looking at metabolic changes and how the hormones in the body – primarily glucose and insulin, but also the appetite hormones leptin and ghrelin and the stress hormone cortisol – were affected by lack of sleep, without allowing the participants to eat more.”
Dr Banks says the take home message for the average person is that sleep is a really important component, along with diet and exercise, in maintaining a healthy body weight.
“If you’re trying to have a good diet and exercise program, sleep really needs to be a component of that, because you’re less likely to achieve your goals without a good night’s sleep,” she says.
Dr Banks’ top three tips for getting a good night’s sleep are:
- Going to bed earlier is better than sleeping in, which can disrupt the circadian rhythm.
- Have a bedtime routine that allows you to unwind – clean your teeth, read a book, relax – a good regular bedtime routine is as good for health as the amount of sleep.
- Don’t have bright lights before bed – and get off technological devices like iPhones, computers and iPads – Facebook and email can wait until morning.