5. A disrupted circadian clock
Joanna Runciman, author of the Radiant Woman’s Handbook, says we need some sunlight so that our body clocks can tell the time. Circadian rhythms regulate everything from metabolism to sleep. If you’re in a windowless office, get outside for your lunch hour and, ideally, your morning and afternoon break. You’ll feel more energized from the brisk walk, and sleep better, too.