yes, sunlight - especially the midday 12 O' clock sunlight with around 390nm wavelength helps a lot. Just like the sunlight during the day a bad aspect is artificial light of the same / similar wave lengths during night - especially after 8:30 PM when our circadian rhythm starts producing Melatonin (called Melatonin onset) which induces sleep. The light acts as a switch, the more delay, the more trouble that we get into. All this is easier said and doing tough ...