Bright Light Therapy Improves Sleep in Cancer Patients

Researchers investigated the effect of systematic light exposure on sleep in a mixed group of fatigued cancer survivors. Results of the randomized controlled trial suggest that systematic bright light exposure could improve sleep for people who have been treated for cancer.

Study participants were randomized to either a bright white light intervention or a comparison dim red light condition. They were provided with a light box and instructed to use it every morning for 30 minutes for four weeks. Wrist actigraphy and the Pittsburgh Sleep Quality Index were administered at four time points during the study to evaluate participants’ sleep.

These are the least squares mean and standard error bars for sleep efficiency over time with mean levels of time in bed (in hours) included for reference. Courtesy of Journal of Clinical Sleep Medicine, American Academy of Sleep Medicine.

The pilot study results 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. This improvement was sustained three weeks after the intervention. In contrast, the dim light group remained at low sleep-efficiency levels on average for the entire study. Medium to large effect sizes were also seen in sleep quality, total sleep time, and wake after sleep onset for participants using the bright lights.

The study took place at Icahn School of Medicine at Mount Sinai, and comprised 44 people who had completed treatment for cancer and met criteria for clinically significant fatigue. Participants had an average age of 54 years and 75 percent were women.

“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 professor Lisa M. Wu.

The researchers noted that larger-scale studies are needed to test the efficacy of systematic light exposure to treat sleep disturbances in people who have been treated for cancer.

The research was published in the Journal of Clinical Sleep Medicine (doi: 10.5664/jcsm.6874).