Using tools like morning sunlight, exercise, and proper timing of food intake can help set a predictable circadian rhythm for better sleep, while during the middle of the day, limiting caffeine intake and being mindful of the clock-delaying effects of exercise can optimize your sleep.

Different factors predict the best and worst nights of sleep, and these factors vary from person to person.

Cultural factors influence sleep patterns globally, with some regions, like the Middle East, having significantly later bedtimes due to lifestyle choices.

Eating early in the day supports your biological clock and increases alertness, but it's not necessary for everyone.

Melanopsin retinal ganglion cells in the eyes help regulate our circadian rhythms by responding to light, signaling when it's day or night, and influencing sleep and alertness.

The concept of first sleep and second sleep is often misrepresented; there's no strong biological evidence supporting the idea that humans are designed to sleep in two distinct phases.

The first phase of the day, 0 to 8 hours after waking, is characterized by elevated norepinephrine, epinephrine, and dopamine, which support an alert and focused state.

Disruptions in circadian clock function are closely associated with digestive issues, mental focus issues, depression, anxiety, and exacerbation of major psychiatric disorders like OCD and ADHD.

Viewing light in the afternoon helps regulate dopamine production and prepares your body for better sleep by reducing retinal sensitivity to light at night.