The prevalence of obesity and sleep disorders follow a similar upward trend, which also suggests this link between these two modern scourges: more than a third of adults in rich countries do not get enough sleep (6 or 7 hours per night), due to various lifestyle factors, including stress, screen time, smart devices, and lack of boundaries between personal and professional life.
Sleep, an indicator of diet quality
Numerous studies have documented the link between poor quality or insufficient sleep and the risks of high blood pressure, high cholesterol, and atherosclerosis. Lack of sleep is linked to obesity, diabetes and inflammation, all factors in cardiovascular disease.
Finally, sleeping too much or too little has been shown to increase the risk of stroke, heart attack, and death.
The study: This is the analysis of data from the S-LiTE randomized controlled trial, conducted among 195 adults, aged 18 to 65 years, who were obese (BMI: 32 to 43 kg/m2) and who had followed a very restrictive diet (800 kcal/day ) for 8 weeks. These participants had lost an average of 12% of their body weight. Participants were randomized to one year of a weight loss maintenance regimen with a daily injection of placebo (49 participants), a daily injection of the weight-loss drug liraglutide 3 mg (49), 4 exercise sessions per week or a combination of both treatments (49). Sleep duration was measured using data from accelerometers worn by study participants before and after the low-calorie diet and after 13, 26, and 52 weeks of weight maintenance. Sleep quality was measured using the Pittsburgh Sleep Quality Index (PSQI): lower scores indicate better sleep quality, ranging from 0 for best to 21 for worst quality sleep. The analysis reveals that:
- On the 8-week low-calorie diet, sleep quality and duration improved in all participants;
- after one year of weight maintenance, participants in the exercise group maintain good quality sleep,
- participants who do not exercise significantly lose sleep quality;
- liraglutide treatment does not appear to cause any significant effect on sleep quality or duration;
- those who sleep badly<6 horas por noche) aumentan su IMC en 1,3 kg/m2 durante la fase de mantenimiento del peso de 1 año frente a los que duermen bien (>6 hours per night);
- poor sleepers (PSQI score > 5) at baseline increase their BMI by 1.2 kg/m2 during the weight maintenance phase compared to good sleepers (PSQI score < 5).
If the study is observational and shows associations and not causal relationships, sleep seems an interesting marker of weight maintenance and loss. It’s possible that, in the other direction, improving sleep in obese people could help limit weight regain.