How matching workouts to body clock can cut risk of heart disease

Timing workouts to match a person’s preference for mornings or evenings could reduce the risk of heart problems, a study has found. 

Patients who exercised according to their chronotype, which is the body’s genetic inclination to sleep or wake up at certain times, were found to have lower blood pressure and better sleep quality, experts said. The study, published in the journal Open Heart, found this was particularly true for people who had high blood pressure or other heart risks.

While researchers acknowledged that further studies are needed, they said the findings “support the inclusion of chronotype assessment in exercise prescriptions for cardiometabolic prevention”. They added: “Personalised, time-matched exercise interventions may become a practical strategy in clinical and public health settings, potentially leading to better outcomes and improved engagement.”

SimpleImages/Getty images

Scientists from the UK and Pakistan conducted research in the city of Lahore and assessed the chronotypes of 150 people aged between 40 and 60 using a questionnaire and 48-hour measurements of core body temperature. People typically fall into the category of either early bird or night owl.

All patients had at least one heart risk factor, such as high blood pressure, obesity or a lack of exercise. They were then randomly assigned to groups for exercise that either matched their chronotype or did not, with workouts scheduled between 8am and 11am, or 6pm and 9pm.

kleber cordeiro/getty images

A group of 134 people completed all 60 exercise sessions over 12 weeks. Of these, 70 were early birds, 34 of whom had exercise times matched to their chronotype, while 64 were night owls, with 30 matched to their preference for evening. A number of measures such as blood pressure and fasting glucose levels were taken before the trial and three days after.

The study found that risk factors for heart problems, aerobic fitness and sleep quality improved in both groups over the 12 weeks. However, matching exercise to chronotype reduced blood pressure more, along with improving functions such as heart rate, aerobic capacity and sleep quality compared to those who were mismatched.

The benefits were particularly pronounced in sleep quality, aerobic fitness and reduced blood pressure, according to the study. Although improvements were observed across both chronotypes, overall due to the benefits of regular exercise in both groups, the effects were larger in those whose activity time reflected their stated profile of morning lark or night owl. 

Reacting to the findings, Dr Rajiv Sankaranarayanan, a consultant cardiologist and executive trustee of the British Cardiovascular Society, said: “From a UK perspective, this study’s findings are highly relevant to preventive cardiology within the NHS, where scalable, cost-effective interventions are essential.

“Incorporating simple chronotype assessment into lifestyle advice could enhance adherence and outcomes, particularly in patients with hypertension or cardiometabolic risk.

“However, before widespread implementation, validation in more diverse, real-world UK populations, including shift workers and multi-ethnic cohorts, is needed. Overall, this study supports a shift toward more personalised, circadian-informed exercise prescriptions in routine cardiovascular care.”