You may want to get more shut eye the next time you visit your doctor for a vaccine.
Research now shows that people who slept less than six hours per night after receiving the three-shot course of the hepatitis B vaccine produced less antibodies than those who got more than seven hours of snoozing at night.
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"Based on our findings and existing laboratory evidence, sleep may belong on the list of behavioral risk factors that influence vaccination efficacy," lead author Dr. Aric Prather, a clinical health psychologist and Robert Wood Johnson Foundation Health & Society Scholar at UCSF and UC Berkeley, said in the press release. "While there is more work to be done in this area, in time physicians and other health care professionals who administer vaccines may want to consider asking their patients about their sleep patterns, since lack of sleep may significantly affect the potency of the vaccination."
Sleep is an important and necessary part of life. According to the National Sleep Foundation, at least 40 million Americans say they have sleep problems, but more than 60 percent of adults have never been asked about the quality of their sleep with a doctor.
People who were awake for more than 19 hours scored substantially worse on performance and alertness tests than those who were legally intoxicated, the National Sleep Foundation reported. Getting less than seven hours of sleep a night for a week has also been shown to impair motor performance and alertness, and lack of sleep has been shown to affect hormone levels, increase diabetes and obesity, increase cardiovascular disease and change the immune system response.
Those with altered sleep schedules may also have some negative health consequences. One study showed that shift workers were more likely to have heart problems, while another showed that sleeping with dim lights was linked to more depression in mice.
"Sleep needs to take on a larger priority when we think about our health. As scientific evidence continues to converge, it's my hope that sleep becomes an important topic of discussion, both in the doctor's office, in our schools and on the health policy level," Prather told TIME.
For the study, which was published in the August 2012 issue of SLEEP, researchers studied 70 men and 55 women between the ages of 40 to 60 who received a standard hepatitis B vaccine. Antibody levels were measured right before the second and third shots, as well as six months after the third vaccine. The subjects were also asked to keep a sleep diary to record their bedtime, wake time and sleep quality, and 88 of them wore electronic sleep monitors.
Out of the 125 subjects, 18 did not receive adequate hepatitis B protection from the vaccine. Those that slept fewer than six hours per night produced less antibodies and were 11.5 times less likely to be unprotected by the vaccine than those who got more than seven hours of sleep. The quality of sleep didn't affect the number of antibodies produced. The results took into account the person's age, sex or body mass index. Researchers also considered the person's level of psychological stress at the time since previous research has shown that stress can change vaccine effectiveness.
"Sleeping fewer than six hours conferred a significant risk of being unprotected as compared with sleeping more than seven hours per night," the scientists wrote.
The researchers believe that sleep helps regulate the immune system, therefore a lack of sleep may have had negative effects on the immune system that resulted in the production of less antibodies. The results however do not imply that lack of sleep causes there to be less antibodies, but that there is a strong association between dozing and how well the vaccine works.