This study is an experimental interventional study for two groups with pretest and posttest analysis. The subjects of the study met the inclusion criteria and were recruited by intention sampling method. They were randomly assigned to the experimental group and the control groups. This is a single-blind study with sunlight exposure as intervention. Appropriate clothing, skin protection measures were given. The calf portion of feet, forearms and hands were exposed to sunlight for at least 30 minutes per day, at least 14 days of exposure with intensity at least 10000lux over duration of 4 weeks. A total of 46 patients were recruited and 4 have lost follow up. 21 patients from each group have completed the study. The research tools include: depression status (Taiwanese depression scale,TDS), physical activity function (Barthel Index), the severity of cognitive function (mini-mental state examination,MMSE) and severity of stroke (National institutes of health stroke scale,NIHSS). Each patient was evaluated 3 times during the study: on the day of enrollment (pre-test), 2 to 4 weeks since enrollment (1st post-test) and 6-8 weeks after enrollment (2nd post-test). Statistical analysis was performed with the following variables: depression, cognitive function (MMSE), severity of stroke (NIHSS) and the Barthel Index for daily function.

The participants in the experimental and control groups were subjected to a pre-test measurement after they were recruited. For the experimental group, the first post-test measurements were taken right after the participants completed the sunlight therapy (two to four weeks after the start of the intervention), and the second post-test measurements were taken one month after the intervention was completed (six to eight weeks after the start of the intervention). For the control group, the first and second post-test measurements were taken two and six weeks, respectively, after they started receiving standard care.

At the start of intervention, the researchers conducting this study instructed the experimental group to fill out a sunshine exposure duration record sheet. The participants used symbols on the record sheet to indicate the day's weather, such as sunny, partly sunny, and cloudy and rainy. Sunshine records were excluded on cloudy and rainy days, while records were taken on partly sunny days with sufficient sunshine, and participants had to expose themselves outdoors to the sun in an outdoor environment; they were not allowed to expose themselves to the sun from an indoor environment through glass. Participants had to take appropriate protective measures on their own beforehand, such as wearing breathable clothing, visors or sunglasses, and applying sunblock. Throughout the implementation of the sunlight therapy, participants were allowed to rest and drink in shady areas if they had any discomforts (dizziness, hyperthermia), so as to avoid overexposure to sunlight. If they had a burning skin sensation or itchy skin, they were allowed to rinse their skin with cold water, iced water, or ice cubes, or to apply ice cubes on their skin for three to five minutes, so as to lower their skin temperature and alleviate skin allergies. They were advised to call for a medical examination or to contact the researchers if their symptoms persisted.