It is one of the more unusual challenges that face Olympic athletes chasing gold: how to ensure their bodies and minds are ready to compete at peak level at times when they would normally be tucked up in bed.

Competitors in athletics will in some cases be in action after 11pm during the Rio 2016 Games, while some swimming events will continue past midnight. The volleyball schedule also regularly runs into the following day and the beach volleyball medals will be decided after 1am.

Luckily expert help is at hand. Like most major teams in the run-up to Rio 2016, the Brazilian Olympic Committee is calling in specialist sleep consultants to make sure that athletes are ready to perform late-night heroics.

"It is not a time which is propitious to physical performance," says sleep consultant Marco Túlio de Melio, who is advising the Brazilian team. "In fact, it's the worst time, when the body temperature curve is decreasing and performance is declining after reaching its peak between 6pm and 10pm."

Crucial role

According to scientists, sleep begins with a shallow stage before moving to a deeper stage and then into so-called slow-wave sleep, characterised by delta wave activity in the brain. This is a restful stage which is essential to athletic performance; growth hormones are released during this period of sleep. The last stage, REM (Rapid Eye Movement) sleep, is believed to play a crucial role in functions such as memory and cognition.

"Athletes need these final stages for their decision-making processes – for choosing whether to shoot left or right, for getting the start right in athletics and swimming, for everything that depends on reaction time," Melo says.

Brazilian Olympians Fernanda Garay, Thiago Pereira and Fabiana Murer will compete in late-night events (Photos: CBV/CBDA/CBAt)

Later to bed

The sleeping mechanism is also closely related to the digestive system. The body remembers the time when food is consumed at night and the time when sleep begins. José Elias de Proença, who works on the physical preparation of the Brazilian women's volleyball team, says that athletes will have to "trick their metabolism" ahead of matches that start at 10.30pm.

Athletes will try to delay the release of melatonin, a hormone which plays an important role in the timing of sleep, by adapting their eating times to the timing of the matches.

In the weeks before the start of the Rio 2016 tournament, volleyball players will also be exposed to artificial light at this time of the night in order to tune their bodies into the Olympic schedule. The team has even experimented with special glasses that shine tiny lights directly onto their eyes, all to make sure that they are at their very best when competition begins on 6 August.