Sunlight during the day, especially in the morning, helps regulate your body’s sleep cycle. If your circumstances prevent you from getting sunlight, consider an at-home light therapy lamp which emulates sunlight throughout the day.
The science: The body’s circadian rhythm is a 24 hour internal clock which controls the natural sleep/wake cycle. It is controlled in the brain by the hypothalamus and is affected by outside factors such as environmental lightness and darkness. Studies have found that getting sunlight every morning acts to restore the human circadian rhythm (Smith & Trinder, 2005).