Time-of-day moderate-to-vigorous physical activity and all-cause mortality in individuals with type 2 diabetes

ABSTRACT

There is no clear evidence for the best time of day for physical activity in benefitting health among individuals with type 2 diabetes. This study was aimed to examine whether there is an optimal time of day for physical activity to increase longevity. In this cohort study of 904 patients with type 2 diabetes, we fitted a Cox model with restricted cubic spline to examine the association of moderate-to-vigorous physical activity (MVPA) and time of day with all-cause mortality. Compositional data analysis was used to examine the association of time spent in sedentary behaviour (SB), light-intensity physical activity (LIPA), morning MVPA, and evening MVPA with all-cause mortality. MVPA was inversely associated with all-cause mortality in a curvilinear manner (P-value for nonlinearity<0.0001). The interaction between MVPA and time of day was not significant (P-value for interaction=0.11). Substituting evening MVPA with morning MVPA was not associated with appreciable changes in all-cause mortality. There is no evidence that the time of day moderates the association of MVPA with all-cause mortality. Patients with higher levels of MVPA had lower mortality regardless of the timing of MVPA. Patients with type 2 diabetes should engage in regular physical activity whenever possible.

KEYWORDS:

• Physical activity
• timing
• mortality
• restricted cubic splines
• compositional data analysis

Disclosure statement

No potential conflict of interest was reported by the author(s).

Author contributions

TM created the concept and design of the manuscript, developed the first draft of the paper, did the literature review, and did the data analysis. YJX did the data analysis and contributed to critically revising the manuscript. TB did the literature review and contributed to critically revising the manuscript. CL did the data analysis and contributed to critically revising the manuscript. All co-authors approved the final manuscript.

Data sharing

The National Health and Nutrition Examination Survey data are available at http://www.cdc.gov/nchs/nhanes.htm.

The linked mortality file is available at the following address: https://www.cdc.gov/nchs/data-linkage/mortality-public.htm.

The NHANES study was approved by the National Center for Health Statistics Research Ethics Review Board.

Additional information

Funding

The author(s) reported there is no funding associated with the work featured in this article.