Blue light to replace caffeine.
OL bronze medalist Jeanette Ottesen was one of the Danish swimmers who used blue light to improve her reaction speed during the Rio Olympics.
It is not easy to be at your best as an Olympic swimmer when your biological clock (circadian rhythm) has been knocked off kilter. The recently completed Olympic Games were held in Brazil, which is five hours behind Denmark—and the semifinals and finals were held between 10 p.m. and midnight.
As a result, the swimmers faced two challenges. The time difference was relatively easy to deal with, requiring them simply to travel to Rio well in advance of the competition and to stick to their familiar training, mealtimes and sleep patterns. The other, more difficult, challenge was for them to stay awake and in form for the late competitions.
In order to improve the swimmers’ reaction time and ensure they had a good night’s sleep, DTU Fotonik worked with Team Danmark to develop a special light concept. The light was installed in all shared areas and rooms at the swimmers’ hotel, illuminating the rooms with varying levels of blue light during the day to support their circadian rhythms.
Plenty of light
“The body gears down when darkness falls. Therefore, we compensated for the lack of daylight by ensuring there was plenty of light in the rooms. To keep the swimmers at their best in the hours immediately preceding the competitions, we had the bulbs light up with an ultra-high level of blue light. This tricks the body into believing that it has to be active because it is the middle of the day,” explains Jakob Hildebrandt Andersen, Research Assistant at DTU Fotonik.
In recent years, DTU Fotonik has acquired new knowledge about the importance of light for the health and well-being of elderly people in particular. One of the effects of blue light is that it reduces the level of the hormone melatonin, which makes us tired. Melatonin is important to people’s health and to the circadian rhythm.
Research indicates that the blue light can improve people’s mood, boost energy levels and even have a positive effect on short-term memory, learning capacity and the circadian rhythm as a whole.
Swimmer Jeanette Ottesen was one of the Danish Olympians who used the blue light in Brazil. She was also one of the swimmers who made use of the light immediately before competing as a part of her bespoke preparation routine. As the history books show, Jeanette Ottesen was a member of the team that took bronze in the 4 x 100 metre medley relay.
Even before the Olympics, DTU Fotonik and Team Danmark had run tests to check whether the light produced the desired effect on the Olympian swimmer. Reaction tests demonstrated that Jeanette Ottesen could improve her reaction speed by around 15 metres per second by exposing herself to blue light 20 minutes before the test.
“The first time I heard that the light could improve my swimming, I could well imagine it. When you are exposed to bright light you become wider awake than if you’re sitting in a dark room,” she says.
Jeanette Ottesen thinks that in particular, the light is a good substitute for the caffeine she previously used before competitions. And the benefits are clear as day. It can take up to a day for caffeine to leave the body, while the blue light has a much shorter ‘half life’. This means that using the blue light eliminates the risk of ruining your sleep the night before an important competition.
It is the first time Danish swimmers have used blue light with a view to improving their reaction speed and sleep. Jakob Hildebrandt Andersen explains that blue light is particularly effective in relation to short distance disciplines such as sprinting and swimming.
Article by Christina Tækker, DTU Online News