Everyone knows that getting sufficient sleep is important for your general health and wellbeing. But more research is linking poor sleep to the obesity epidemic. So does this mean that good sleep is key when it comes to making weight loss easier?
Studies have shown links between short sleep duration and obesity in adults. Increasing sleep from <6hrs to 7-8hrs per night has been associated with attenuation of weight gain.
A more recent focus in sleep research is sleep variability. Previous observational studies have linked high variability with increased BMI and waist circumference. Sleep variability may be linked to a disruption of circadian rhythms, which is also linked with obesity.
However, it is not known whether short sleep duration or a higher variability in sleep can predict less weight loss in response to lifestyle interventions. Researchers designed a study to examine the effects of sleep duration and variability on weight and adiposity measures over 12 months.
A secondary study was designed based on the findings of the PREDIMED trial – a 6-year primary prevention trial based on lifestyle interventions for weight loss.
In the original trial, participants were allocated to intervention or control group. The intervention group underwent a program with a Mediterranean diet with energy restriction, physical activity promotion and behavioural support. The control group consumed an unrestricted Mediterranean diet and received traditional health care.
Researchers analysed the results of a subsample group of 1986 subjects. Participants had overweight/obesity and metabolic syndrome. The average age of participants was 65 years, with 53% male participants and 47% female participants.
Sleep duration and sleep variability was measured using an accelerometer worn on the wrist, which was worn for 8 consecutive 24hr periods by participants.
Anthropometric measurements were taken regularly throughout the trial, but for the purpose of the secondary study, data from the first 12 months was used. This included body weight, BMI and waist circumference.
Several associations were found during the analysis. When compared to the first tertile, the third tertile of sleep variability lost an average of 0.5kg less weight, and had a BMI that was 0.2 higher on average. There was no significant difference in weight circumference between the tertiles.
Participants who slept less than 6 hours per night saw a 0.8cm lesser reduction in waist circumference compared to participants who slept 7-9 hours. However, there was no significant difference between these two group in terms of body weight or BMI changes.
The researchers concluded that adequate sleep duration was a predictor of greater success of lifestyle interventions for obesity, as was less sleep variability.
Shorter sleep duration was associated with a lesser reduction in waist circumference. Greater sleep variability was associated with less weight loss and lower reduction of BMI.
However, it was noted that the participants were elderly Mediterranean people with metabolic syndrome. Because of this, the researchers did warn that results cannot be extrapolated to other populations without further research to confirm the effects of sleep on weight loss efforts.
Papandreou, C., Bulló, M., Díaz-López, A., Martínez-González, M.A., Corella, D., Castañer, O., Vioque, J., Romaguera, D., Martínez, A.J., Pérez-Farinós, N. and López-Miranda, J., 2019. High sleep variability predicts a blunted weight loss response and short sleep duration a reduced decrease in waist circumference in the PREDIMED-Plus Trial. International Journal of Obesity, p.1.