Matching the timing of exercise to an individual's natural body clock, or chronotype, may help lower the risk of cardiovascular disease in people already at risk, according to research published in Open Heart on Apr. 15.
The study suggests that aligning exercise schedules with a person's innate tendency toward morning or evening alertness can lead to better sleep quality and greater reductions in key cardiovascular risk factors such as high blood pressure, fasting glucose levels, and low-density lipoprotein (LDL) cholesterol. The researchers say these findings could influence how exercise is prescribed for those vulnerable to heart disease.
Researchers assessed the chronotypes of 150 adults aged 40 to 60 who had at least one cardiovascular risk factor—including high blood pressure, obesity, or a sedentary lifestyle—using questionnaires and core body temperature measurements. Participants were then randomly assigned either to exercise at times that matched their chronotype (morning larks exercised between 8:00 and 11:00 a.m.; night owls between 6:00 and 9:00 p.m.) or at mismatched times. All participants completed five sessions per week of supervised moderate-intensity aerobic activity for twelve weeks.
Results showed improvements across both groups after three months. However, those whose workouts aligned with their chronotype saw larger benefits. Systolic blood pressure dropped by an average of 10.8 mm Hg among matched participants compared with a decrease of just 5.5 mm Hg in the mismatched group; this effect was even more pronounced among individuals who started with high blood pressure.
"This study adds to a growing body of evidence suggesting that the timing of exercise when aligned with an individual's internal biological clock can significantly enhance health outcomes," write the researchers. They further explain: "Aligning exercise with chronotype may entrain peripheral clocks in skeletal muscle, adipose tissue, and vasculature more effectively, enhancing metabolic efficiency and reducing inflammation, both critical factors in cardiometabolic health." The team concludes: "Integrating the principle of 'chrono-exercise,' scheduling workouts according to an individual's internal biological clock, may offer a novel and impactful approach to enhancing outcomes in preventive cardiovascular and metabolic health."
Dr Rajiv Sankaranarayanan from the British Cardiovascular Society commented on these findings by saying: "From a UK perspective, this study's findings are highly relevant to preventive cardiology within the NHS... Incorporating simple chronotype assessment into lifestyle advice could enhance adherence and outcomes... However, before widespread implementation, validation in more diverse... populations is needed."
