Recent research published in Diabetologia (the journal of the European Association for the Study of Diabetes [EASD]) shows that morning and afternoon physical activity are related to a lower risk of developing type 2 diabetes across all population levels of education and income, but found no statistically significant association between evening physical activity and risk type 2 diabetes. The study is by Dr. Caiwei Tian, Harvard University, Cambridge, MA, USA, and Dr. Chirag Patel, Harvard Medical School, Boston, MA and colleagues.

​​​​​​​Study: Association between timing and consistency of physical activity and sort 2 diabetes: a cohort study on participants of the UK Biobank. ​​​​​​​Image Credit: Creative Cat Studio / Shutterstock

Physical activity is a preventive factor for type 2 diabetes, but its timing and consistency (in contrast with the general sum of physical activity) have been relatively unexplored. Accelerometer-based devices that measure physical activity provide a brand new opportunity to objectively measure behavior throughout the day and week. It has been shown that midday–afternoon but not evening physical activity is related to a lower risk of mortality compared with morning physical activity, but the connection with type 2 diabetes stays understudied. On this recent study, the authors analyzed the connection between morning, afternoon, or evening physical activity and consistency (routine) and risk of type 2 diabetes.

A cohort of 93,095 UK Biobank participants (mean age 62 years) with no history of type 2 diabetes wore a wrist-worn accelerometer for 1 week. The authors converted accelerometer information to estimate the metabolic equivalent of task (MET) (a standard measure of physical activity), summing MET-hours of total physical activity. MET-hour physical activity captures every kind of activity undertaken by a person throughout the day and measured with the accelerometer, including chores, walking, and vigorous activity. The authors measured accomplished METs inside three time segments (morning, afternoon, and evening), divided as 06:00–12:00 hours (morning), 12:00–18:00 hours (afternoon), and 18:00–24:00 hours (evening).

The authors quantified the consistency of physical activity by analyzing the variance or difference of everyone’s activity from their very own personal average. Those with smaller deviations were more consistent, and vice versa. The authors also considered the intensity of exercise: moderate-to-vigorous physical activity (MVPA) and vigorous physical activity (VPA) in association with type 2 diabetes incidence.

The authors observed protective associations of physical activity, with each 1-unit increase in MET being related to a ten% and 9% reduction in risk of type 2 diabetes within the morning and afternoon, respectively. Nonetheless, there was no statistically significant association between evening physical activity and risk of type 2 diabetes.

The connection with morning and afternoon physical activity was largely linear, meaning that those individuals with more MET-h accomplished had a much lower risk of developing type 2 diabetes than those with less (10% / 9% per MET-h, for morning and afternoon, respectively). 

The authors thought that lifestyle aspects, reminiscent of the quantity of sleep and dietary intake, would influence the quantity of physical activity within the morning, afternoon, and evening undertaken, and subsequently, the role activity has in diabetes risk. To handle how these aspects influence physical activity, the authors considered these aspects of their analytic models. They found that when adjusting for lifestyle aspects, associations for MET-hours with different times of day became more precise. 

Consistency of MET-measured physical activity was not related to type 2 diabetes, but intensity was – each MVPA and VPA were related to decreased risk for type 2 diabetes in any respect times of the day. The authors say their study is the primary report on the effect of consistency of activity and explain: “The consistency or routine of physical activity was not strongly related to type 2 diabetes. In other words, individuals who exercise a smaller period of time more incessantly are at no lesser risk for diabetes than individuals who exercise the identical total amount, but with less of a routine.”

Unlike previous studies, the authors highlight that certainly one of the strengths of this recent research is that they used the MET has the target physical activity measurement to take all every day activities under consideration. Their results were also statistically significant after adjusting for other lifestyle variables, including sleep, weight loss plan, education, and income.

The authors conclude: “Our findings support that total physical activity but not its consistency over the week could also be a vital factor impacting type 2 diabetes risk. The timing of activity may play a job in mitigation of diabetes risk.”

They add: “Our study showed an association with diabetes risk between morning and afternoon versus evening physical activity. The findings also suggest it is useful to incorporate some higher intensity activity to assist reduce the chance of developing diabetes and other heart problems.”