Summer is coming to an end, and with fall and winter come cold and flu season. Want to give your annual flu vaccination a powerful boost? Start sleeping more.
A new study suggests that a lack of sleep may weaken the effectiveness of vaccines in the body. This is the first study to look at sleep and vaccine effectiveness based on “natural” sleep data—that is, information gathered from people sleeping in their normal environment and routine—as opposed to data generated in a laboratory setting. It’s also another indication that low sleep and disrupted sleep habits have a negative effect on immune system function, making us more susceptible to illness.
Researchers at the University of Pittsburgh School of Medicine investigated the relationship of sleep and the effectiveness of vaccine protection among 125 healthy adults between the ages of 40-60. All the adults were vaccinated against Hepatitis B—after being screened to make sure they’d had no exposure to the virus. Vaccination for Hepatitis B occurs in three stages, with two doses given thirty days apart, followed by a third and final dose administered 6 months after the initial vaccination. Vaccines work by introducing a weakened or inert version of the disease into the body, which stimulates the immune system to produce its own antibodies to protect against the disease.
Researchers measured the strength of antibody response before the second and third doses of the Hepatitis B vaccine. They also tested participants again 6 months after the final immunization, at which point the vaccine would have delivered the full force of its protection against the virus. Throughout the vaccination process, researchers tracked participants’ sleep using wrist monitors, and also had participants keep sleep journals where they reported not only sleep amounts, but also details on the quality of their sleep. They found:
People who slept less produced fewer of the vaccine-inducing antibodies during the preliminary stages of immunization.
People who slept less were less likely to be fully protected at the end of the vaccine cycle. Researchers found 15% of participants were not experiencing full protection against Hepatitis B 6 months after completing the vaccination. People who slept fewer than 6 hours a night were more than 11 times as likely to be among this group, compared to those who slept more than 7 hours nightly.
The association between sleep and vaccine effectiveness was limited to sleep quantity: researchers did not find that quality of sleep or efficiency of sleep were associated with vaccine effectiveness.
There’s a great deal more to understand, in future research, about the relationship between sleep and the efficacy of vaccines. But I think it’s safe to say that this is more complicated than making sure you sleep well the night before a vaccination. We’re still learning about how sleep affects the immune system, and how chronic lack of sleep can undermine normal immune function and make us more vulnerable to disease and infection. This study is the latest in a growing body of research about the relationship between sleep and the immune system:
I wrote recently about this study, which showed that extreme lack of sleep can be as damaging to the immune system as stress. Researchers who exposed healthy adults to extreme sleep deprivation (29 consecutive hours of wakefulness) found that participants’ immune systems were significantly disrupted from their normal functioning, in ways that mirrored the response of the immune system to stress.
Anyone who has had the flu knows: we sleep differently when we’re sick. Research seeking to understand why, and studies that explore the relationship between sleep and infections disease indicate that the sleepiness we feel when we’re sick may be an immune system response to the presence of infection.
Research into sleep and the immune system has tremendous importance for our health, for treatment of chronic and infectious disease, and for preventive care. But investigating the immune-sleep connection also may be helping us get closer to understanding the core mysteries of the purpose of sleep. The increasing evidence of the complicated relationship between sleep and immune function is leading scientists to suggest that one of the basic reasons for sleep is this function: to regulate and sustain the immune system.
Do yourself and your body’s immune system a favor. Commit to a strong, consistent sleep routine. You’ll not only be gaining the immediate benefits of restful, ample sleep, you’ll also be protecting your body’s most essential and important defense system.
Michael J. Breus, PhD
The Sleep Doctor™