It is well known that in the senior population, many factors can contribute to poor mood: low nutrient status, hormonal imbalance, changes of life, other health conditions, and loss of loved ones.
One study from the Netherlands suggests that changes in circadian rhythm and how your brain's biological clock operates can also play an important role. A recent study of 89 depressed patients over the age of 60 years were split into two groups: one group was given 1 hour of either 7500 lux bright pale blue light therapy in the morning or dim red light, as a control.
The elderly patients who had the blue light therapy had better mood, better sleep, and a more balance melatonin response. Melatonin is the hormone released in the early evening when the outside light dims. This hormone is a crucial anti-oxidant and cancer-preventive, as well as needed to relax the body into a sound sleep.
This is an interesting study, for these patients with depression did not have seasonal affective disorder, a typical use of light therapy. This suggests that early light therapy in other depressed populations may be useful.
Clinically, as a naturopathic physician, I do recommend my patients try have some outside light exposure, in the form of a walk or run, preferably in the morning once the sun comes up. This seems to improve patient mood and sleep cycles as well.