Fifty-eight sedentary males participated in a 12-week exercise program that resulted in significant reductions in body fat.
Both morning and evening exercise groups experienced reductions in body fat after 12 weeks.
Morning exercise led to decreased total cholesterol and triglycerides, with significant changes observed as early as week 4.
Shortened sleep latency was noted in both exercise groups, with the morning group experiencing advancements in sleep-wake cycles.
Improvements in vascular function were observed in both groups, with evening exercise showing greater enhancements in blood flow and carotid artery dilation.
Systolic blood pressure was lowered in both exercise groups, indicating cardiovascular benefits from the intervention.
Simplified
Modern life and rising stress have contributed to increased sleep disorders and metabolic and cardiovascular diseases. While exercise is known to be an important health intervention, the optimal timing for its effectiveness remains uncertain. This study aims to investigate the effects of a 12-week timed exercise program on sleep, lipid profiles, and vascular function. Fifty-eight sedentary males were divided into three groups: morning exercise (ME) at 6-8 a.m., evening exercise (EE) at 6-8 p.m., and control group (CON) without exercise. The 12-week intervention involved moderate-intensity aerobic exercise (≥ 150 min/week). Sleep was assessed using the Munich ChronoType Questionnaire (MCTQ) and Dim Light Melatonin Onset (). Metabolic indicators were assessed through body composition and blood biochemical tests. Ultrasound imaging was performed to evaluate at the common carotid artery. Both exercise groups reduced body fat after 12-week exercises, with ME showing significant reductions as early as week 4. Total cholesterol and triglycerides in ME also decreased. Shortened sleep latency was observed in both exercise groups, with DLMO and sleep advanced in ME. Although both exercise groups showed decreased stiffness and increased wall shear stress, EE demonstrated greater enhancements in blood flow rate, center-line velocity, carotid artery dilation and lowering systolic blood pressure. A 12-week aerobic exercise significantly improves physical health in sedentary adults. Morning exercise (6-8 a.m.) is particularly effective for rapid body fat reduction, lowering plasma cholesterol and triglycerides, and advancing sleep-wake cycle. Evening exercise (6-8 p.m.) is more effective for enhancing vascular function.Trial registration: Chinese Clinical Trial Registry, ChiCTR2400094208, 18/12/2024.
Key numbers
12 weeks
Body Fat Reduction
Both exercise groups showed significant decreases in body fat mass after 12 weeks.
Total cholesterol decreased after morning exercise
Cholesterol Decrease
Morning exercise group showed significant reductions in total cholesterol and triglycerides.
6.70±2.40 min
Sleep Latency Reduction
Sleep latency was reduced in the morning exercise group after 12 weeks.
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Declarations. Ethics approval and consent to participate: Participants received detailed information about the experimental procedures and potential risks, and each provided written informed consent. This research was approved by the Bioethics Committees of the Dalian University of Technology (DUTSKHP230224-01), with all procedures following the principles of the Declaration of Helsinki for research involving human subjects. Competing interests: The authors declare no competing interests.
