New study reports that sleep efficiency of people treated for cancer improves after systematic morning bright light exposure.
The results of the study showed that mean sleep efficiency, the percentage of time in bed when the person is sleeping, improved to clinically normal levels in the bright light therapy group. In contrast, the dim light group remained at low sleep efficiency levels on average for the entire study. Medium to large effect sizes also were seen in self-reported sleep quality, total sleep time and wake time. The study results were published in the January 15, 2017, issue of the Journal of Clinical Sleep Medicine.
The research team, led by principal investigator William H. Redd, PhD, professor in the Department of Population Health Sciences and Policy at Icahn School of Medicine at Mount Sinai, studied 44 people who had completed treatment for cancer and met criteria for clinically significant fatigue at screening. Participants had an average age of about 54 years, and 75 percent were women. According to the authors, sleep disturbances are reported by cancer patients at a significantly higher rate than in the general population. Between 23 and 44 percent of cancer patients experience insomnia symptoms even years after treatment.
Participants were randomized to either a bright white light intervention or a comparison dim light condition. They were provided a light box and instructed to use it every morning for 30 minutes for four weeks. Sleep was evaluated using wrist actigraphy and the Pittsburgh Sleep Quality Index. “Systematic light exposure using bright white light is a low-cost and easily disseminated intervention that offers a feasible and potentially effective alternative to improve sleep in cancer survivors,” said Wu.
According to Light Therapy Market Report published by Coherent Market Insights, this therapy is often used in the treatment of conditions such as depression, jet lag, and sleep disorders. Light therapy is also used to treat seasonal affective disorder (SAD), as it helps reset the circadian rhythms, which controls the sleep-wake cycle. The authors of the study reported that larger-scale studies are required to test the efficacy of systematic light exposure to treat sleep disturbances in people who have been treated for cancer.