By Janice Heng

Joggers who dislike morning runs can feel vindicated - they are not just being lazy.

The human body apparently performs better in the evening, a time when it is primed for action, allowing for an easier workout.

Dr Patrick Goh, consultant sports physician at SportsMed Central clinic, says: 'For most people, body temperature increases, muscle strength improves, hand-eye coordination and reaction time also improve in the late afternoon to evening, from about 4 to 7pm. It is part of the body's natural 24-hour biorhythm.'

Humans have a 24-hour biorhythm known as the circadian rhythm. This 'body clock' affects eating and sleeping patterns.

Physiological factors such as body temperature, blood pressure and hormone levels also vary according to the cycle.

But people who exercise in the early morning are not necessarily getting it wrong.

Dr Jason Chia, consultant sports physician at the Singapore Sports Medicine Centre, says sports performance may not be significantly affected by one's biorhythm.

He adds: 'The bulk of research suggests that if there is a difference in performance, it is small, limited to certain aspects of performance and can be overcome with a prolonged warm-up, at least in the context of swimming.

'Just as important is the fact that there can be large differences in this biorhythm between individuals.'

Such differences are influenced by habits such as sleeping hours and meal times.

In practice, the verdict is mixed.

'I feel that I perform better in the late afternoon,' says teacher Steven Lim, 33, who runs from 5 to 7pm on most weekdays. 'It feels like I have more strength.'

For polytechnic student Galvin Tham, who usually runs in the evening, the time of day for exercise is immaterial.

'There's no difference,' says the 19-year-old, who was out for a jog at 1.30pm when LifeStyle caught up with him.

The midday sun did not faze him as the path he took ran through a forested area.

That just-do-it spirit is one which doctors commend. Ultimately, practicality should outweigh scientific considerations, doctors say.

Dr Low Wye Mun, a sports medicine physician at The Clinic at Cuppage, says: 'The best time of the day for a busy person to exercise is any time he or she can make it.'

The important thing is getting some exercise, regardless of the time. Dr Chia says: 'If you have a tight schedule, some exercise at any time of the day is better than none.'

This article was first published in The Straits Times.