9. Make Late Nights an Exception
Set aside ample time to get the restorative shut-eye that your body needs (most experts advise seven to nine hours a night). In a study conducted at the Mount Sinai School of Medicine, in New York City, women who were well rested had more active killer cells (white blood cells that attack germs) than did women who felt tired. To make sure you nod off quickly, keep your room cool, quiet, and dark. Try to avoid caffeine, alcohol, and strenuous exercise at least three hours before bedtime.
10. Resolve to Really Relax
Carve out time for whatever helps you unwind―be it yoga, painting, or crossword puzzles―on a regular basis, and ideally every day. “That chronic, teeth-grinding kind of stress suppresses circulation of your immune cells, inhibits your body’s responses to invaders, and elevates levels of cortisol,” says Bruce McEwen, Ph.D., the director of the Harold and Margaret Milliken Hatch Laboratory of Neuroendocrinology, at Rockefeller University, in New York City.