If you can, bundle up and head outside for 10-20 minutes first thing in the morning. Exposing your eyes to early morning light helps increase dopamine—a neurotransmitter that helps support innate immunity1.
Seeing natural light upon waking also helps boost your cortisol, which helps wake you up, energize you for the day, and regulate your circadian rhythm. In addition to helping you fall asleep at a reasonable hour at the end of your day, a healthy circadian rhythm has been found to support immune function2 (even outside of sleep health).