Sleep problems linked to poorer brain health

Research carried out in the United States suggests that a poor supply of oxygen to the brain during sleep could play a role in poor brain health and nerve cell death.

Posted on 10th December 2014

Research carried out in the United States suggests that a poor supply of oxygen to the brain during sleep could play a role in poor brain health and nerve cell death. The study is published on 10 December in the Journal of Neurology.

Nerve cells are dependent on oxygen for communication, even while we are asleep. Interruptions to oxygen supply by conditions such as sleep apnoea – characterised by pauses in breathing during sleep – can affect overall brain function. To get a full picture of how ‘sleep health’ affects the brain, the researchers studied 167 Japanese American men who had been members of a large ageing study in Hawaii. The men, who had an average age of 84 in 1999-2000, took part in sleep studies where researchers assessed their blood oxygen levels as well as monitoring the various phases of their sleep cycle.

The men who took part in the sleep studies generously donated their brains after death so that the researchers could look for signs of nerve cell damage. The research team found that those who had poor brain oxygenation during sleep had an increased number of microinfarcts – small areas of brain tissue damaged by oxygen starvation. They also linked poor oxygenation during the REM stage of sleep – the lightest sleep cycle, where dreams are more vividly recalled – to higher levels of brain inflammation and increased nerve cell death.

The researchers also found that longer periods of ‘deep sleep’ were associated with less brain shrinkage, although there was no clear link between this and memory and thinking skills. None of the sleep measures investigated were associated with the build-up of proteins involved in the progression of Alzheimer’s or dementia with Lewy bodies.

Dr Laura Phipps, Science Communications manager at Alzheimer’s Research UK, said:

“While this study suggests that conditions such as sleep apnoea could cause small amounts of damage to the brain, we cannot conclude from these results that these sleep disturbances contribute to dementia risk. A good night’s sleep is important for proper brain function in the short term, but we need
larger and longer studies in people before we can determine whether disruptions to particular stages of the sleep cycle could impact on memory and thinking skills in later life. A healthy diet, plenty of exercise and quitting smoking can help to lower dementia risk and anybody concerned about their memory should speak to their GP.”

Posted in Science news