The Clock in the Chest

Cardiovascular prevention has always meant diet, exercise, and blood pressure. This piece makes the case for a sixth factor: the rhythm of light and dark your body actually lives in. Drawing on circadian research from Mount Sinai's Light and Health Research Center, it traces how the brain's master clock governs sleep, melatonin, and cortisol — and why the hour you wake up may matter for your heart as much as the hour you go to bed.