Let’s say you’re one of the responsible individuals who will get a flu vaccine each year, boosting your own resilience while giving herd immunity to those around you. You may think that a single flu shot will work perfectly, each and every time, for all individuals. But you’d be informed to know that not everyone responds to a vaccine the same way, and a vaccine is only effective if your body actually reacts to it and generates the antibodies.
A remarkable discovery in 2002 demonstrated that sleep can profoundly impact your response to a standard flu vaccine. In this study, healthy young adults were separated into two groups: one was restricted to four hours a night of sleep for a week, while the other was allowed to have seven or more hours of sleep. At the end of the week, each group received a flu shot, followed by lab work to determine how effective these individuals were in generating an antibody response.
Those participants who obtained seven or more hours of sleep generated a more powerful antibody reaction, while those getting four hours of sleep had a paltry 50% immune response to the same vaccine.
What if the sleep-deprived individuals got more sleep afterwards, so that they can go on to produce the antibodies needed? Unfortunately, even if those patients got recovery sleep after the sleep deprivation, they never got back to developing the full immune reaction to the flu shot. Once they miss out on the benefits of sleep in an acute moment, you cannot regain the benefits simply by trying to catch up on lost sleep.
A similar phenomenon has been seen in the area of cancer. Natural killer cells, an elite and powerful squadron within the ranks of your immune system, identify foreign elements and eliminate them. One of their targets are malignant (or cancerous) tumor cells. When you receive less sleep, your malignant cells are not cleared out as quickly, and your risk of developing cancer goes up. So much so that the World Health Organization has classified nighttime shift work as a probable carcinogen.
With each passing year, more malignant tumors are linked to insufficient sleep. Another larger, European study demonstrated that sleeping six hours or less was associated with a 40% increased risk of developing cancer relative to sleeping seven hours or more.
Not getting sufficient sleep when fighting a battle against infections, cancer, and other threats is like pouring gasoline on an already aggressive fire.