Considerations

Adenosine builds up the longer we are awake, creating a “sleep drive” or hunger. It binds to receptors in the brain that normally promote wakefulness. Caffeine promotes wakefulness by blocking adenosine receptors. Each person must determine how caffeine impacts them and at what times of day it is...

Light, especially sunlight, is the strongest “time giver” (zeitgeber) for circadian rhythms and sleep. Melanopsin-containing retinal ganglion cells detect light and signal the central circadian clock, called the suprachiasmatic nucleus. Bright light in the morning advances your clock, while light...

We have an internal “clock” that regulates sleep-wake cycles over roughly 24 hours (circadian). It is most directly set by light exposure, especially sunlight. Sunrise triggers a rise in cortisol, promoting wakefulness. 12–16 hours later, the pineal gland releases melatonin, promoting sleepiness....

Circadian rhythms arise from the central clock in the brain but impact the timing of physiological events throughout the body. They regulate hormones, body temperature, metabolism, hunger, immune function, and more. Disrupting them can lead to weight gain, diabetes, depression, and dementia over ...

• Get sunlight exposure, ideally first thing after waking. Use artificial light if needed. This sets your circadian clock and hormonal rhythms for the day.
• Avoid overhead and electronic lights, especially blue light, 1–2 hours before bed.
• Stick to a consistent sleep schedule, ...