Effect of daylight on subjective general health factors in elderly

This before-after clinical trial investigated the effect of daylight on morning and night melatonin، subjective general health using GHQ questionnaire، sleepiness and alertness on elderly who lived in nursing houses. Nineteen nursing home residents participated voluntarily. They exposed to daylight from 9 to 10 A. M. and from 4 to 5 P. M. for 6 weeks. General health of all participants was evaluated using general health questionnaire (GHQ) as well. Also we used of KSS and VAS questionnaire foe assessment of sleepiness and alertness. Baseline morning and night melatonin levels were 25. 39 (±19. 75) pg/ml، and 40. 3 (±21. 55) pg/ml respectively. Daylight exposure significantly affected morning melatonin at 7:00 A. M. but had no significant effect on night melatonin at 8:00 P. M. Mean score of general health changed 36. 31 to 29. 89 (P=0. 003). Karolinska sleepiness scale (KSS) and Visual Analogue Scale (VAS) showed increase sleepiness and decrease alertness from 3:00 to 7:00 A. M. Sleepiness decreased and alertness increased during 1:00 P. M and 20:00 P. M. Overall day light exposure may delay sleep phase and circadian rhythm problems in elderly people. Anxiety and insomnia could be improved with daylight exposure. Our findings suggest that elders should be exposed to scheduled daylight in morning and evening for prevention and improvement of mental disorders. Adequate light should be provided for elder’s homes and nursing house. We have proposed to further study with a larger sample size be done to assess effect of daylight on GHQ'' subscales.