A literally sleepy person is resourceful and clever. However, if someone is tired, it looks mentally underperform. The same applies to the effect of alcohol consumption where the cognitive abilities suffer. According to a study, both effects apparently also have a common basis. Those who are severely affected by alcohol, whose mental performance also suffer intensely from lack of sleep. Apparently, adenosine plays a central role in both effects. The findings could help prevent accidents caused by over-fatigue, the researchers say.
The backgrounds that led to the study are certainly familiar to many. How well someone copes with lack of sleep varies from person to person clearly: There are people who are particularly dizzy due to lack of sleep and mentally dull. Others, however, can stay awake for two days without their mental abilities suffering. The same applies to alcohol consumption: Some people are extremely drinking-resistant – despite a high blood alcohol level in their blood, their reaction time and mental performance deteriorate comparatively little.
“We wanted to find out whether there is a connection between the two phenomena and have investigated this in a cooperation project of the German Aerospace Center (DLR) and Forschungszentrum Jülich,” reports Eva-Maria Elmenhorst from DLR. The researchers conducted a ten-minute reaction test with 50 subjects who had not slept for 38 hours. On another day, the same study participants took an individually calculated amount of vodka and again, their reaction time was determined.
Alcohol’s sensitive people are also sleep-deprived
It turned out that those who had done well in the reaction test under the influence of alcohol could also suffer little from sleep deprivation. Conversely, the lack of sleep was particularly troublesome for those participants who had also reacted the same with alcohol. An experiment in which the subjects slept shortened over five days.
“It thus became apparent that both susceptibilities to alcohol and sleep deprivation are controlled by a common biochemical mechanism”. As a result Adenosine effect came into question. This substance plays an important role in the energy balance of the body. It is already known that the longer someone stays awake, the more adenosine accumulates in a person’s brain. It acts like an electric dimmer, which turns the nerves from awake to tired, creating the need for sleep.
Adenosine (Adenosine is both a chemical found in many living systems and a medication) seems responsible
Adenosine influence under alcohol reaction, the researchers have now examined in the study by the method emission tomography (PET), which can make adenosine receptors visible. In seven subjects, the scientists were able to show in this way that the nerve cells in the brain shortly after consumption of alcohol provide significantly more receptors on their surface and thus more molecular switches to switch to tired. Alcohol in this way strengthens the tiring effect of adenosine and is different for each individual. The researchers explain. “This confirms our belief that susceptibility to sleep deprivation and alcohol depend on differences in the adenosine system,”
According to the researchers, their findings could now have practical relevance: Depending on their predisposition, recommendations for active and rest periods could be applied to pilots or train drivers, for example, and prevent human failure due to fatigue. “Together with partners from the US, we are working on computer models that can be used for improved fatigue risk management, which also feeds the current data. This allows us to further refine the models and also take into account the influence of alcohol consumption on human performance, “says David Elmenhorst.