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More light or a nap help against soup coma
After lunch, the performance drops significantly for many people. However, this so-called "soup coma" can be effectively avoided by bright light or a short nap, reports the research team around Rachel Leproult of the Université Libre in Brussels. Together with the Swiss scientist Rémy Schmitz from the University of Geneva, Leproult and her Belgian colleagues examined the influence of daily meals on cognitive performance. Their results were published in the journal "PloS One".
The scientists analyzed the cognitive performance of 25 subjects before and after each of the three daily meals. It became clear that after lunch a significant drop in performance occurs. They also looked at how the mental faculties changed when the subjects took a nap for food or were exposed to bright light. Previous studies have already reported that bright light and a short nap in between can improve cognitive performance in people with a lack of sleep, the researchers report. This effect has now been confirmed in terms of performance degradation in the "soup coma".
A nap and bright light after lunch increase efficiency. (Image: katie_martynova / fotolia.com) Cognitive Powerful checked after lunch
The 25 healthy adults were divided into two groups for the experiment, with 15 either taking a nap or staying awake and ten being irradiated with light blue or dark orange light (as a placebo). In the first group, subjects could take a 30-minute nap after lunch or watch a 30-minute documentary instead. The other group watched the documentary after dinner either under bright, blue or under dark, orange light. The researchers then examined the subjects' mental performance using a so-called "task-switching test", which switches between different tasks in order to test cognitive flexibility.
Bright light with the same effect as a nap
Both after the siesta and in bright light, the score achieved in the test after lunch increased significantly, which is due to a reduced fatigue of the subjects, Leproult and colleagues report. The bright light and a short nap therefore effectively counteract the performance break after lunch. "Bright light has similar benefits to a short nap in terms of cognitive flexibility," the researchers write. So anyone who has no opportunity to take a short break after lunch can counteract the drop in performance with bright light. However, given the low number of participants, the validity of the current study is rather limited. Here further investigations are necessary in order to be able to make a clear statement. In particular, the improvement of cognitive performance by bright light, however, seems to open promising new possibilities. (Fp)