Lack of sleep activates the body’s defence mechanisms

Mar 16 2005

A lack of sleep is considered a threat situation, which activates the body’s defence mechanisms. This is the same type of response that protects the body against viruses and bacteria as well as in stress situations.

If we sleep for less time than the body requires, a sleep debt accrues, which must be paid by getting what is known as recovery sleep. When the body gets the necessary recovery sleep, it heals and rejuvenates.

“Based on the length of the waking period preceding sleep, we can accurately predict how much recovery sleep will be needed. The objective of our research is to determine what cellular-level mechanisms in the brain store information on the length of the waking period and increase the amount of sleep,” explains Academy Research Fellow Tarja Stenberg, who, along with her research team, is studying the cellular-level mechanisms of extra sleep using animal models.

According to Stenberg, during an extended waking period, the basal forebrain begins to see an accumulation of adenosine, an indicator of metabolic state, which seems to play a pivotal role in initiating recovery sleep. “According to our latest measurements, the amount of nitrogen oxide accumulated in the same area of the brain is required to initiate recovery sleep. We were surprised to find that the amount of nitrogen oxide was increased by the enzyme, iNOS, which is usually not present in the brain at all – except for in an inflammation reaction,” says Stenberg.

The reaction is the body’s way of defending itself against viruses and bacteria, but even in stress situations the iNOS enzyme has been found to activate in the brain. This presentation of iNOS in the brain is an indication of the fact that the body considers itself under threat and defends itself. “What’s new and worrying is that the brain considers sleep deprivation to be a threat, which triggers this defense reaction,” states Stenberg.