“Go ahead and get a good night’s rest and you will be well again tomorrow for sure”. As a matter of fact a long sleep is almost as effective as a strong antibiotic if you are suffering from an infection. Early risers suffer much more frequently from a lack of appetite, have about a double as high risk to get diabetes or die from a heart attack more often. But the share of population sleeping less than six hours on a regular basis was never higher than today.
Early risers are cold snatchers
The headlines in medical research tell us: The one who spends only a quarter or even less in his bed trifles with his health. Scientists of Jan Born‘s working group at the University of Luebeck showed several years ago that a lack of sleep after a hepatitis vaccination lowers the antibody titer. A good night’s sleep supplies the body with hormones such as prolactin, dopamine or the growth hormone – all three of them stimulate the immune system. Sleep and immune system are closely interweaved which also shows an experiment at the Carnegie Mellon University in Pittsburgh/USA. Sheldon Cohen and his colleagues looked for 150 late sleepers and early risers and trickled a solution with rhinoviruses in their noses. Early risers became sick even more frequently the less they slept at night. Overall they developed a cold 3 to 6 times more often than late sleepers with eight or more hours per night.
While sleep deprivation effects on concentrativeness are well examined (DocCheck reported), we know only little about the interconnections to the immune system. More than 20 cytokines are effective in the immune system and at same time influence sleep. But only two of them have been examined more closely. Neurons in the hypothalamus, hippocampus and the brain stem react to Interleukin-1 and tumor necrosis factor-alpha and extent the non-REM-sleep (NREM) of apes, cats and rabbits. The immune system discharges large amounts of both antigens during contact with bacterial antigens from the cell wall. Laboratory animals as well as test persons get sleepy and reduce their REM-sleep while other phases of sleep are extended.
Sleep sees to T-cell-balance
With the financial support of the special research unit 654 of the Deutsche Forschungsgemeinschaft (German Research Association), groups at the universities of Luebeck and Kiel explore the correlation between sleep, circulation and immune system. Thomas Bollinger from Luebeck recently published new results of his work. He found out: Sleep withdrawal disturbs the balance between the production of T-helper cells and their control authority – the regulatory T-cells. The number of these cells which dam an overflowing immune response fluctuate in a circadian rhythm, highest during the night.
On the other hand overactive T-helper cells are hardly dammed at around seven o’clock in the morning. Whoever sleeps little rattles this rhythm. Because during a good night’s sleep the body releases IL-2 – the cytokine without an effective immune response would not function and which contributes to the reproduction of the helper cells. In contrast the production of regulatory T-cells is mostly independent from sleep, which means an adaptive immune response works a lot harder without sleep.
The close connection between sleep and an effective defence against microbes seems to be a driving force in evolution. In a comparison of length of sleep of 26 different mammals the long sleepers had the most immune cells in their blood. Brian Preston at the Max-Planck-Institut für Evolutionäre Anthropologie (Institute for Evolutionary Anthropology) in Leipzig/Germany shows also that mammals with a longer night rest trade in the advantage of significantly fewer infections although at the expense of time for provision of food.
Energy glutton body temperature
Mark Opp at the University of Michigan in Ann Arbor/USA researches the correlations between sleep and the immune system for a long time. In his recent report in the March issue of Nature Reviews Neuroscience he also points to the connection between the regulation of body temperature and sleep. During a long uninterrupted NREM sleep the difference between body temperature at night and during the day is the largest. Only during the phase of sleep the body can increase its temperature by shivering and – if necessary – raise it to turn into a fever. On the other hand fever hinders the microbe production and stimulates the immune system. To raise the temperature by only one degree though, the body has to increase its blood circulation by 13 percent in order to produce enough energy. The length of REM sleep decreases while the length of NREM phases increases when you are sick.
If you want to be night owl and early bird at the same time you do not only risk a higher rate of mistakes at work but also a weakening of the immune defence. People provoking their immune system with vaccinations, journeys to tropical countries or working in offices with snot noses should at least recharge their energy supply with enough sleep on a regular basis.