Gold, Silver, Bronze – time of day can make the difference

The way in which we perform over the course of a day is affected by our biological clock. Scientists from the University of Groningen compared times from swimmers in the heats, semi-finals and finals of four Olympic Games. After removing factors that were unrelated to the biological clock, they observed that these swimmers performed best in late afternoon. Their performance in the morning and late evening was sub-optimal. The difference caused by the biological clock could be a deciding factor between winning gold and silver, or between winning and not winning a medal. Since individuals ‘biological clocks may differ, it could pay off to shift the time of peak performance towards the most important race by changing the athletes’ light exposure during specific times of the day. “

Biological clocks have sizeable effects on the performance of elite athletes. This conclusion was drawn by chronobiologists from the University of Groningen after studying the times achieved by swimmers in four different Olympic Games. Shifting the clock to reach peak performance at the right time could make the difference between winning and losing. The results were published on 8 October in the journal Scientific Reports .

‘In many sports, the differences between coming first or second, or winning no medal at all, are very small,’ explains Renske Lok, first author of the paper and former PhD student at the University of Groningen. ‘We wondered whether an athlete’s biological clock was playing a role.’ This clock determines our bodies’ daily rhythms: it regulates physiological characteristics such as core body temperature and blood glucose levels. ‘And we know that peak performance usually coincides with the peak in core body temperature,’ says Lok.