Individuals with type 2 diabetes who are night owls not only go to bed later than morning types, or larks, but also have a more sedentary lifestyle, suggests new research that points to a role for lifestyle modifications.

Looking at more than 630 patients who wore an accelerometer for a week, UK scientists found people with an evening chronotype spent nearly 30 minutes/day more being sedentary than those with a morning chronotype, and the former spent 56% less time engaged in moderate-to-vigorous activity per day.

"The link between later sleep times and physical activity is clear: go to bed late and you're less likely to be active," said second author Alex V. Rowlands, PhD, of the Sansom Institute for Health Research, University of South Australia, Adelaide, in a press release.

"As sleep chronotypes are potentially modifiable, these findings provide an opportunity to change your lifestyle for the better, simply by adjusting your bedtime," he added.

The research was published by Joseph Henson, PhD, NIHR Leicester Biomedical Research Centre and Diabetes Research Centre, University of Leicester, UK, and colleagues in BMJ Open Diabetes Research & Care.

Henson said maintaining a healthy weight and blood pressure in diabetes is vital and "makes understanding the factors that can mitigate a person's propensity to exercise extremely important."

Moreover, the findings underline the "massive need for large-scale interventions to help people with diabetes initiate, maintain, and achieve the benefits of an active lifestyle. For people who prefer to go to bed later and get up later, this is even more important," he added.

Circadian Misalignment Can Be Altered

The team note previous studies have shown that people with an early evening chronotype may be more susceptible to metabolic alterations linked to obesity.

As previously reported by Medscape Medical News, a pooled analysis of more than 140,000 nurses suggested that rotating night work every 5 years increased the risk of developing type 2 diabetes by 30%.

Another study suggested that the increased risk of diabetes seen among individuals with an evening preference is likely due to a combination of poor diet, erratic eating patterns, and irregular sleeping patterns.

However, it is unclear whether physical behaviors differ in individuals with type 2 diabetes based on chronotype.

The researchers therefore examined data from the ongoing Chronotype of Patients with Type 2 Diabetes and Effect on Glycemic Control (CODEC) observational study of individuals from the UK.

Participants were asked to wear an accelerometer on their nondominant wrist for 7 days to measure physical behaviors, divided into sleep and sedentary, light, and moderate-to-vigorous physical activity.

Complete data were available for 635 individuals from the study. The average age of participants was 63.8 years and 34.6% were women. The average body mass index was 30.9 kg/m².

Chronotype preference, as assessed using the Morningness-Eveningness Questionnaire, indicated that 25% of participants had a morning chronotype, 52% an intermediate, and 23% an evening chronotype.

Compared with participants with a morning chronotype, those with an evening preference spent an extra 28.7 minutes/day in sedentary time and 33.5 minutes/day less performing light-intensity physical activity.

Evening chronotypes also engaged in less moderate-to-vigorous physical activity by 9.7 minutes/day versus people with a morning chronotype — a 56% reduction.

The intensity of the most active 60 minutes of the day was also lower for individuals with an evening chronotype, as was the average acceleration and intensity gradient of exercise.

Evening chronotypes also had later sleep onset than morning chronotypes, by an average of 1 hour and 44 minutes, and the most active 30 minutes of the day consequently occurred an average of 1 hour and 42 minutes later.

The team say that the lower physical activity levels seen in evening chronotypes may be influenced by social and physical environmental factors.

"Moreover, personal/socially imposed alterations in sleep, as demonstrated by the differences in sleep and physical activity timing, may result in a 'circadian misalignment,'" they note.

They suggest, for example, "An enforced early wakeup may reduce the likelihood of engaging in physical activity due to the resulting tiredness or time constraints of family responsibilities in the evening."

"This may make a natural preference for engaging in physical activity later in the day more difficult to achieve."

They nevertheless believe that physical activity could be one way of encouraging people with an evening preference to adopt a morning chronotype.

"Due to its wide-ranging health benefits, minimal cost and side effects, and accessibility, physical activity may be an attractive nonpharmacological treatment option that could also theoretically improve circadian misalignment, through alterations in temperature regulation and/or hormone levels," they conclude.

The research was supported by the National Institute for Health Research Leicester Biomedical Research Centre.

The authors have reported no relevant financial relationships.

BMJ Open Diab Res Care 2020;8:e001375. Full text

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Cite this: Night Owls With Diabetes Have More Sedentary Lifestyle Than Larks - Medscape - Oct 05, 2020.