Proper sleep. Immune cells that fight off infections, like natural killer cells and T-cells, are activated when you sleep. If you do not naturally wake up on time (without an alarm clock) reassess the time you’re going to bed. If you wake up during the night feeling hungry, shaky, or anxious your blood sugar may be low. Avoid skipping meals and ensure you’re not overeating sugar without adequate protein and fats in your diet. If you’re waking up frequently to urinate check your daily sodium intake. And consider a midday nap when you do not have a good night’s rest.