Late sleepers ‘have more trouble keeping active’

People who keep later sleeping hours tend to be more sedentary and generally find it harder to exercise, according to a US study.

Led by the Northwestern University in Chicago, the research looked at 123 healthy adults with a self-reported sleep duration of at least 6.5 hours. Sleep variables were measured over seven days, with physical activity and attitudes toward exercise evaluated using questionnaires.

It was found that so-called "night owls" reported more sitting time and more perceived barriers to exercise, including not having enough time to work out and being unable to stick to an exercise schedule, regardless of when they actually went to bed or woke up.

This suggests that circadian factors should be taken into consideration as part of exercise recommendations and interventions, especially for less active adults.

Principal investigator Dr Kelly Glazer Baron said: "Sleep timing should be taken into account when discussing exercise participation. We could expect that sleep timing would play even a larger role in a population that had more difficulty exercising."

It is increasingly understood that circadian rhythms can have a significant impact on health. A study earlier this year revealed, for example, that maintaining normal day/night cycles can help intensive care patients to recover from heart attacks.