Sleeping less than seven hours a night 'raises common cold risk'

Washington, Jan 13 (ANI): Sleeping less than seven hours a night greatly raises the risk of catching a cold, according to a new study.

The research indicates that those who sleep approximately seven to eight hours per night have the lowest rates of heart disease illness and death.

However, there has previously been little direct evidence that poor sleep increases susceptibility to the common cold.

For the study, Sheldon Cohen, Ph.D., of Carnegie Mellon University, Pittsburgh, and colleagues examined 153 healthy men and women (average age 37) between 2000 and 2004.

Participants were interviewed daily over a two-week period, reporting how many hours they slept per night, what percentage of their time in bed was spent asleep (sleep efficiency) and whether they felt rested.

They were then quarantined and administered nasal drops containing the common-cold-causing rhinovirus.

For five days afterward, the study participants reported any signs and symptoms of illness and had mucus samples collected from their nasal passages for virus cultures; about 28 days later, they submitted a blood sample that was tested for antibody responses to the virus.

The researchers found that the less an individual slept, the more likely he or she was to develop a cold.

Lower sleep efficiency was also associated with developing a cold-participants who spent less than 92 percent of their time in bed asleep were five and a half times more likely to become ill than those whose efficiency was 98 percent or more. Feeling rested was not associated with colds.

"What mechanisms might link sleep to cold susceptibility? When the components of clinical illness (infection and signs or symptoms) were examined separately, sleep efficiency but not sleep duration was associated with signs and symptoms of illness. However, neither was associated with infection," the authors said.

"A possible explanation for this finding is that sleep disturbance influences the regulation of pro-inflammatory cytokines, histamines and other symptom mediators that are released in response to infection," they added.

The study is published in the January 12 issue of Archives of Internal Medicine, one of the JAMA/Archives journals. (ANI)