Too much or too little sleep 'increases inflammation'
Failing to get the recommended eight hours of sleep each night is as damaging to a person's health as high-fat diet or sedentary lifestyle, a new study suggests.
A meta-analysis of data published in journal Biological Psychiatry reports that getting either too much or too little sleep were associated with increases in markers of inflammation.
Dr. John Krystal, editor of the journal, said that it was important that people are conscious of tracking their sleep, with normal sleep duration around seven to eight hours each night, as common sleep disturbances - such as insomnia - have been associated with increased risk of inflammatory disease and mortality. He added that insufficient sleep is considered a public health epidemic by the U.S. Centers for Disease Control and Prevention.
"It is important to highlight that both too much and too little sleep appears to be associated with inflammation, a process that contributes to depression as well as many medical illnesses," he said in a statement.
Inflammation causes a number of substances to increase in volume in the blood stream, for instance, C-reactive protein (CRP) and interleukin-6 (IL-6).
An increase in these substances can be an indication of adverse health conditions, including cardiovascular problems, raised blood pressure and type 2 diabetes. Many previous studies have investigated the mechanism behind the link between sleep and immunity. However, a team of researchers from UCLA recently set out to review 72 past studies on the topic, which included over 50,000 participants from population-based and clinical studies.
The analysis showed that sleep disturbance (poor sleep quality or complaints of insomnia) and long sleep duration (more than eight hours) were associated with increased indicators of two types of inflammation markers. One of the researchers, Michael Irwin, said that sleep disturbance or insomnia should be regarded as behavioural risk factors for inflammation, similar to the adverse effects of high fat diet or sedentary behaviour. Treatments targeting sleep behaviour could be a strategy for reversing the inflammation and reducing risk of inflammatory illnesses.
"Together with diet and physical activity, sleep health represents a third component in the promotion of health-span," he said.