Unlocking the Clock: Optimal Physical Activity Timing for Cardiovascular Disease Prevention.

Area of Science:

• Cardiovascular epidemiology
• Genetics and personalized medicine
• Chronobiology and exercise physiology

Background:

• Cardiovascular diseases (CVDs) remain a leading cause of mortality worldwide.
• Understanding modifiable risk factors like physical activity (PA) timing is crucial for prevention.
• Previous research has not fully elucidated the specific temporal effects of PA on various CVD subtypes.

Purpose of the Study:

• To investigate the causal impact of physical activity (PA) at different times of day on the risk of major cardiovascular diseases.
• To differentiate the effects of PA timing on stroke subtypes, heart failure, atherosclerosis, myocardial infarction, hypertension, and peripheral artery disease.

Main Methods:

• Employed two-sample Mendelian randomization (MR) analyses, both univariable and multivariable.
• Utilized genetic instruments for total PA and 12 specific 2-hour intervals from the UK Biobank.
• Obtained summary-level data for CVD outcomes from large-scale consortia and applied multiple MR estimation methods.

Main Results:

• Morning (6-8 AM) and midday (10 AM-12 PM) PA demonstrated independent protective effects against total and ischemic stroke.
• Specific evening PA (6-8 PM) also showed protective associations with stroke subtypes.
• Certain daytime PA intervals were linked to reduced risk of atherosclerosis and hypertension, though effects varied by subtype and MR method.

Conclusions:

• Physical activity timing is causally associated with the risk of specific cardiovascular diseases, notably stroke, atherosclerosis, and hypertension.
• These findings underscore the importance of considering the timing of exercise for optimizing cardiovascular disease prevention strategies.
• Further research may refine optimal PA schedules for different populations and CVD risks.