Football fans, take note: The outcome of this weekend's Super Bowl, along with other major sporting events, may depend on whether the players are night owls or early birds, a new study suggests.
Scientists found that the performance of competitive athletes varied by as much as 26 percent over the course of a day.
"Even 1 percent makes the difference between winning a race and losing it," said Roland Brandstaetter, a biologist at the University of Birmingham in England and co-author of the study published today (Jan. 29) in the journal Current Biology. [10 Things You Didn't Know About You]
The findings could have big implications for the timing of major sporting events, and how athletes train for them, the researchers said.
Larks and owls
Previous studies have always found that athletes perform their personal best in the evening, but nobody considered body-clock types properly, Brandstaetter told Live Science. All people, not just athletes, fall into categories based on internal biological clocks. People who are more awake earlier in the day are called "larks," whereas those who are more awake at night are known as "owls." Members of a third group have "intermediate" clocks.
These three clock types are determined by genetics, but can be synchronized to the environment, Brandstaetter said.
In the recent study, Brandstaetter and a colleague developed a new test to determine the body-clock types of more than 120 athletes. The researchers chose 20 athletes (all field hockey players) representing the three types (larks, owls and the intermediate group), and gave each athlete a standard fitness test six times in a single day.
The participants showed remarkable variation in their physical performance throughout the day. The amount of time elapsed since their natural waking times — the times when they would get up without help from an alarm clock — was the best predictor of their performance, the researchers said.
The larks reached their peak around midday, whereas the owls tended to perform better in the evening, the researchers found. The group of people with intermediate clocks reached peak performance in the afternoon.
Around the clock training
The message for coaches and athletes is to find out their biological clock type, and try to schedule competitions at the right time of day, Brandstaetter said. It may be possible to shift your clock schedule with training, but only to a limited extent; it’s almost impossible to turn an owl into a lark, for example, he said.
Biological clocks may explain why some soccer teams perform well in their league games, which tend to happen in the afternoon, but underachieve in championship matchups, which often take place in the evening,Brandstaetter said.
"Maybe in future, [soccer] coaches will look into having a good mix of players in their teams," Brandstaetter said.
The findings apply not just to elite athletes, but to everyone, the researchers said. And biological clocks can influence not just athletic performance, but cognitive performance, as well.
Aptitude tests at schools and offices often take place in the morning, Brandstaetter said, so "how many talented people are we missing out on?"