Exercising at times that match someone’s natural preference for mornings or evenings could significantly reduce their risk of heart problems, new research suggests.
Experts say checking whether patients are more “early birds” or “night owls” could be especially useful for those with high blood pressure or other cardiovascular risk factors.
The study, published in the journal Open Heart, focused on chronotypes – the body’s built‑in, genetically influenced tendency to sleep and wake at particular times.
Most people fall broadly into one of two groups: early risers or night owls.
To explore how this might relate to heart health, researchers in the UK and Pakistan assessed the chronotypes of 150 adults aged 40 to 60, using both a detailed questionnaire and 48‑hour monitoring of core body temperature.
All patients had at least one heart risk factor, such as high blood pressure, obesity or a lack of exercise.
They were randomly assigned to groups for exercise that either matched their chronotype or did not, with workouts scheduled between 8am and 11am, or 6pm to 9pm.
Some 134 people completed all 60 exercise sessions.
Of the total, 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.
Several 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 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.
What these findings mean
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.”
Are you an early bird or a night owl? Let us know in the comments
