Tailoring workout times to an individual’s natural preference for mornings or evenings could significantly reduce the risk of developing heart problems, new research suggests.
Experts indicate that assessing whether patients are “early birds” or “night owls” might prove particularly advantageous, especially for those already managing high blood pressure or other cardiovascular risk factors.
The study, published in the journal Open Heart, delved into chronotypes – the body’s inherent, genetically determined tendency to sleep and wake at specific times.
Individuals typically fall into one of these two categories.
Researchers from the UK and Pakistan evaluated the chronotypes of 150 participants, aged between 40 and 60.
This assessment involved a detailed questionnaire and 48-hour core body temperature monitoring.
All individuals in the study presented with at least one heart risk factor, including high blood pressure, obesity, or insufficient physical activity.
Participants were then randomly allocated to exercise groups where their workout schedule either aligned with their chronotype or did not.
Exercise sessions were set for either 8am to 11am or 6pm to 9pm. A total of 134 people successfully completed all 60 planned exercise sessions.
Among these, 70 were identified as early birds, with 34 having their exercise times matched to their preference.
The remaining 64 were night owls, 30 of whom had their workouts scheduled for the evening.
Key health indicators, such as blood pressure and fasting glucose levels, were recorded both before the trial commenced and three days after its conclusion.
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 and blood pressure, according to the study.
The effects were also larger among morning larks than among night owls.
While researchers acknowledge that further studies are needed, they said the findings “support the inclusion of chronotype assessment in exercise prescriptions for cardiometabolic prevention”.
“Personalised, time-matched exercise interventions may become a practical strategy in clinical and public health settings, potentially leading to better outcomes and improved engagement,” they added.
Reacting to the findings, Dr Rajiv Sankaranarayanan, 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.”
