The first of December marks the beginning of Summer in Australia. Every year, come Spring and Summer, I am reminded how much my mood picks up as the days get longer and the sun shines brighter. I feel happier, lighter and more inclined to tackle those difficult tasks.
Although I’ve heard about the use of light exposure in treating depression and Seasonal Affective Disorder, I was interested to know if light exposure can benefit people who do not suffer from mental health problems.
A recent article published in the Journal of Environmental Psychology has investigated this very issue. Researchers Karin Smolders, Yvonne de Kort and Stephanie Van den Berg explored the relationship between daytime light exposure and feelings of vitality among healthy persons during their regular weekday routine. For three days, forty-two adults in the Netherlands wore a light measuring device at eye level and recorded their energy levels on an hourly basis. Ten adults participated twice, resulting in 52 records.
The results showed that participants who experienced higher levels of light exposure also experienced more vitality, even after researchers accounted for individual differences in vitality due to time of day, activity patterns, sleep duration during the previous night, and personal characteristics such as health, light sensitivity, neuroticism, age, gender and preference for daytime or nighttime activities. Shorter periods of light exposure (i.e., 5 to 10 minutes and 1 hour of exposure) were stronger predictors of vitality than periods of more than 1 hour.
The effect of light exposure on vitality was said to be in the same range as other factors that influence energy levels, such as social and physical activities, time of day and the previous night’s sleep duration. The study findings also suggested that light exposure may be particularly beneficial during Winter, in the morning, and when people have experienced low levels of vitality in the previous hour.
More research is needed to determine if light exposure actually causes increased vitality, or if people with more vitality seek out lighter environments. Nonetheless, the findings have strengthened my resolve to spend more time outdoors and to draw my curtains as soon as I wake. With any luck, these tips will help me to navigate my days with a little more energy and a bounce in my step.
Smolders KCHJ, Kort YAW de, Berg, SM van den. Daytime light exposure and feelings of vitality: results of a field study during regular weekdays. Journal of Environmental Psychology. 2013; 36:270-279