Huberman Lab sleep
I learned that for a good sleep rythm, it's important to get sunlight early in the morning. Also it's important to get no light in the middle of the night. Many (mental) health problems will improve with a good sleep cycle. Light in the middle of the night is directly linked to depression. You need to trigger a cortisol spike in the morning with sunlight(shortly after sunrise), which sets a timer for a melatonin release at night. Light is not received through the skin, but through receptors in the eyes. Meditation/yoga nitra/hypnosis can help with relaxation and falling asleep. Naps can be beneficial if short (less than an hour), as can be aforementioned meditation etc.