Randomized trials have found that poor sleep habits may promote obese adults to regain weight after losing weight A new study published at the European obesity Conference (ECO) held in Maastricht, the Netherlands, this year found that not enough high-quality sleep will destroy people's attempts to maintain weight after dieting. In addition, it also suggested that vigorous exercise for about two hours a week can help maintain better sleep.
The study was conducted by medical students Adrian f. bogh, Professor signe s. Torekov, doctoral student Simon B. K. Jensen of the University of Copenhagen in Denmark and colleagues.
"It's surprising to see how obese adults lose weight in such a short period of time, improve sleep time and quality, and exercise while trying to maintain their weight. In addition, it's intriguing that adults with insufficient or poor sleep quality seem to be less successful in maintaining weight loss than those with enough sleep," bogh said
In the UK and the US, more than a third of adults often do not get enough sleep (defined as less than 6 or 7 hours per night, respectively), due to a range of aspects of modern life - including stress, computers, smart devices and blurring the boundaries of work and life.
Not getting enough sleep or poor sleep quality increases the risk of high blood pressure, high cholesterol and arteriosclerosis (fat deposits in the arteries). Not getting enough sleep is associated with obesity, diabetes and inflammation, all of which can worsen cardiovascular disease. Too much or too little sleep has also been shown to increase the risk of stroke, heart attack and death. Some people believe that sleep habits may be a factor leading to weight gain after weight loss.
In this study, the researchers analyzed data from the s-lite randomized placebo-controlled trial to investigate changes in sleep time and quality during diet induced weight loss. A total of 195 adults (aged 18-65 years) with obesity (body mass index BMI 32-43 kg / m2) followed a very low calorie diet (800 kcal / day) for 8 weeks, and they lost an average of 12% of their weight.
Participants were then randomly assigned to a one-year weight loss maintenance period, including daily injections of placebo (49 participants), daily injections of 3 mg of the weight-loss drug liraglutide (49 participants), four times a week of exercise (48 participants), or a combination of two treatments (49 participants). Everyone in the exercise group was encouraged to attend supervised 45 minute courses, twice a week, and two unsupervised 30 minute courses.
Sleep time was measured using accelerometers worn by study participants before and after a low calorie diet and after 13, 26 and 52 weeks of weight maintenance. Sleep quality was subjectively measured by Pittsburgh sleep quality index (PSQI), a self-rated questionnaire. The lower the PSQI score, the better the sleep quality, ranging from 0 for the best sleep to 21 for the worst sleep. Scores greater than 5 are considered poor sleep quality.
To study the relationship between sleep and weight gain, participants were grouped according to their average sleep time (below / above 6 hours / night) or sleep quality (below / above PSQI score) at randomization (after low calorie diet).
The researchers found that after eight weeks of low calorie diet, all participants improved their sleep quality and sleep time. Notably, after one year of maintaining weight, participants in the exercise group maintained self-reported improvements in sleep quality from a low calorie diet, while those in the non exercise group relapsed (mean difference between groups: 1 PSQI score point).
Compared with placebo, liraglutide treatment had no significant effect on any sleep quality or duration.
The analysis also showed that participants who slept an average of less than 6 hours per night at the beginning of the study increased their BMI by 1.3 kg / m2 during the 1-year weight maintenance phase compared with those who slept longer (more than 6 hours per night).
Similarly, people who did not sleep well at the beginning of the study (PSQI score 5 or higher) increased their BMI by 1.2 kg / m2 during the weight maintenance phase compared with those who slept well (PSQI score less than 5).
Professor Torekov said: "the fact that sleep health is closely related to maintaining weight is very important because many of us do not get the recommended amount of sleep needed for optimal health and function. Future research examining possible ways to improve sleep in adult obese patients will be the next important step in limiting weight rebound. Exercise maintained weight loss seems promising in improving sleep."
Despite these important findings, the researchers point out that the study is observational and does not prove that poor sleep can lead to weight change, but suggests that it is likely to be a factor.