After a short night with a hot hunger on chocolate, burgers and other Junk Food to Wake up – this is a phenomenon known to many people. So far, a disturbed hormone household was considered as the reason for this connection. The "fatigue an appetite" but it could also arise quite differently, as researchers at the University of Cologne, now report in the journal "Journal of Neuroscience". They found evidence to suggest that sleep deprivation activates the reward system in the brain, and the desire for fatty Snacks boosts.
The negative effects of too little sleep on health are already proven by several studies. For example, epidemiological studies showed that people with chronic sleep Diabetes have a lack of an increased risk for obesity or type 2. As the main cause for it up to now, the hormonal balance has been seen: Too little sleep take this mess, in consequence of the cravings will be awakened to oily or sweet food, so the adoption.
After dinner, to bed or to the lab
A Team of Julia Rihm, who has been conducting research in the area of Biological psychology at the University of Cologne, introduced this assumption to the test now. The scientists invited 32 healthy, lean men to the laboratory, where they served them on two evenings, with several days interval for a dinner. Afterwards, the participants were instructed to either go home and normal to bed or to stay in the laboratory, where they were kept awake.
On the Morning after the scientists have sent all the subjects in a MRI tube. The activity of your brain recorded while working on a task: The men should explain how great is their willingness to pay for certain Snacks or Non-food money. In addition, it was removed from the blood, to measure your hormone levels, and you should classify your feeling of Hunger on a scale.
Jan Peters, also of the University of Cologne and co-author of the study, the joint analysis of these three factors, the special feature of the investigation: "We have collected both hormonal changes as well as the influence on the behavior and effects on the brain," he said.
More money for Snacks with less sleep
the researchers found that sleep loss increases the subjective value of food in comparison to Non-food products. Although the feeling of Hunger should be the same in both experimental groups, since the participants loose in the bedroom as well as the good night's sleep, which was the same time without food, showed a significant difference: With sleep deprivation, the subjects willing goods, more money for Snacks than for Non-food spend.
"This effect could be expected on the basis of previous studies," concludes neuroscientist Peters. However, hormones are responsible for the blood analyses showed. Rather, the MRI showed increased activity in two brain area is the Amygdala located in the temporal lobe of the brain and to the limbic System, as well as in the Hypothalamus located in the diencephalon.
is reduced In case of over-the reward system will be active
a night of sleep deprivation trigger a cycle, the use of a food-specific, neural reward system, the researchers report. The offer of Snacks seemed like a reward stimulus for the participants of the experiment, the limbic System reacts and here in particular the Amygdala, which affect or pleasure stressed sensations are processed. Why these regions are activated in the case of bleary-eyed people more, needs to be clarified according to Jan Peters in further experiments.More about
Good night, The search for the meaning of sleepJana Schlütter
With the recommendations of the scientists in view of the results of the study restrained: "Apparently, it is in cross-section so that lack of sleep increases the risk for a whole range of health problems, including obesity." The new study is another building block in the explanation of the relationship is clear: "We now understand a piece closer to what mechanism triggers on the neural level this behavior, which is perhaps a rather subordinate role to play." (dpa)