“Generations ago most of the population worked outdoors.. resulting in high Levels of Bright light Exposure”
SAD lights are useful, if you work indoors increasing light with Artificial light has proven to work; “Bright light therapy reduced the risk of SAD incidence by 36%” changing your diet increasing Serotonin Naturally and avoiding Carbs along with SAD Lights is highly beneficial
Researcher Simon N Young in his evaluation of Serotonin in Food also points out the importance of daylight:
“In humans, there is certainly an interaction between bright light and the serotonin system. The mood-lowering effect of acute tryptophan depletion in healthy women is completely blocked by carrying out the study in bright light (3000 lux) instead of dim light.
Relatively few generations ago, most of the world population was involved in agriculture and was outdoors for much of the day. This would have resulted in high levels of bright light exposure even in winter. Even on a cloudy day, the light outside can be greater than 1000 lux, a level never normally achieved indoors. In a recent study carried out at around latitude 45° N, daily exposure to light greater than 1000 lux averaged about 30 minutes in winter and only about 90 minutes in summer among people working at least 30 hours weekly; weekends were included.
In this group, summer bright light exposure was probably considerably less than the winter exposure of our agricultural ancestors. We may be living in a bright light–deprived society.
Meditation increases Serotonin
In one recent study, meditation was reported to increase release of dopamine -self-induced changes in mood can influence serotonin synthesis. This raises the possibility that the interaction between serotonin synthesis and mood may be 2-way, with serotonin influencing mood and mood influencing serotonin.
SAD Lights are an alternative way of getting bright light if you work indoors; in a factory, office or from home all day.