Editor's note: In addition to having a good night sleep, adults who want to reduce their risk of getting colds may take high doses of vitamin C (2 grams a day) and vitamin D (4000 IU a day) and regularly do physical exercise.
Individuals who get less than seven hours of sleep per night appear
about three times as likely to develop respiratory illness following
exposure to a cold virus as those who sleep eight hours or more,
according to a report in the January 12 issue of
Archives of Internal Medicine, one of the JAMA/Archives journals.
Studies
have demonstrated that sleep deprivation impairs some immune function,
according to background information in the article. 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.
Sheldon Cohen, Ph.D., of
Carnegie Mellon University, Pittsburgh, and colleagues studied 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 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 write. “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.”
The results suggest that seven to eight hours of sleep per night is a reasonable target, they conclude.
(Arch Intern Med. 2009;169[1]:62-67. Available pre-embargo to the media at www.jamamedia.org.)
Editor’s
Note: This study was funded by grants to the Pittsburgh Mind-Body
Center from the National Heart, Lung and Blood Institute, by the
National Institute of Allergy and Infectious Diseases and by
supplementary funds provided by the John D. and Catherine T. MacArthur
Foundation Network on Socioeconomic Status and Health. Please see the
article for additional information, including other authors, author
contributions and affiliations, financial disclosures, funding and
support, etc.
