A study recently published in the Journal Sleep evaluated the effects of sleep timing on metabolic health factors, including weight status and insulin resistance. It seems that there are numerous factors beyond poor diet and lack of physical activity that contribute to being overweight and obesity, as well as other associated diseases.
Getting adequate sleep each night is essential for both one’s cognitive and physical health. Experts recommend getting between seven to eight hours of sleep each night, with more or less than that leading to negative consequences. It is not enough to just be getting adequate hours of sleep, just as meal timing is essential for maintaining a healthy weight; sleep timing is extremely important for good health and weight as well.
Proper sleep timing includes having a similar bedtime each day in accordance to circadian rhythms that are aligned with the dark-light cycles. Meaning you should be going to bed at night time when it is dark and waking up during light hours. Your bedtime should also be consistent from day-to-day and avoid erratic changes, such as staying up late on weekends or going to bed early on other nights.
Achieving regular sleeping patterns can be quite challenging among shift workers. Previous studies have demonstrated that among this population, they are more likely to be overweight and obese and have a higher prevalence of insulin resistance and type 2 diabetes. Among a general adult population, erratic sleep patterns has been associated with increased risk of obesity and poor glycemic control among adults with diabetes.
Since sleep patterns is a behavior that can be easily modified and has previously been associated with metabolic health, researchers evaluated four areas of sleep timing including average bedtimes, variability in bedtimes, delayed bedtimes, advanced bedtimes and the effects on metabolic health.
The study included 338 multi-ethnic women between the ages of 48 and 58 from the Study of Women’s Health Across the Nation (SWAN). Participants completed questionnaires and sleep diaries as well as participated in interviews, blood drawings and measurements. Study design included both cross-sectional findings as well as prospective ones.
Findings revealed from the cross-sectional study that having greater variability in sleeping patterns and earlier bedtimes on some nights were both associated with increased BMIs. Further, variability in betimes and late nights were associated with increased insulin resistance. Their prospective results demonstrated that having delayed bedtimes more often increased the likelihood of insulin resistance, thus increasing risk of diabetes.
While this study is a good stepping stone to further investigate the correlation between offset sleeping patterns and its impact on metabolic health, there are several limitations in drawing concrete conclusions. Sleeping patterns are factors that can be modified; however, further prospective and interventional studies are warranted.
“The results are important because diabetes risk increases in midlife women. Our study suggests that irregular sleep schedules may be an important piece of this puzzle. The good news is that sleep timing is a modifiable behavior. Metabolic health was better in women who had more regular sleep schedules, including regular bedtimes across weekdays and weekends,” stated study author, Marcia Hall.
Source for Today’s Article:
Taylor, B.J., et al., “Bedtime Variability and Metabolic Health in Midlife Women: The SWAN Sleep Study,” SLEEP, 2016; 39 (02): 457 DOI: 10.5665/sleep.5464.