The Link Between Sleep and a Strong Immune System There are numerous strategies related to improving the function of your immune system, from eating healthy foods to drinking enough water to getting consistent exercise. One more big one for the list? Making sleep a priority. STRONGER IMMUNITY WITH SLEEP The connection between sleep and immune function is well-documented, and biodirectionally linked — which means if your immune system is down, then you’ll likely have poor sleep, but that applies in the other direction, too. For example, one study looked at blood samples from identical twins and found those with shorter sleep duration had a depressed immune system compared to the sibling who slept better. That can make you more likely to get sick if you’ve been exposed to a virus, says Dr. W. Christopher Winter, president of Charlottesville Neurology and Sleep Medicine, and author of “The Sleep Solution.” Also, if you end up getting ill, poor quality sleep and its immune-suppressing effe