Light Therapy May Ease Fatigue and Improve Sleep for Breast Cancer Survivors

Light Therapy May Ease Fatigue and Improve Sleep for Breast Cancer Survivors

Wearing a light therapy visor cap at home improved sleep and eased fatigue in women who completed treatment for early-stage breast cancer.
Apr 1, 2022.

When women who completed treatment for early-stage breast cancer wore a light visor cap — a type of light therapy — they had better sleep quality, fewer sleep disturbances, and lower levels of fatigue, according to a small study.

The research was published in the March 2022 issue of the journal Chronobiology International. Read the abstract of “Evaluating chronotypically tailored light therapy for breast cancer survivors: Preliminary findings on fatigue and disrupted sleep.”


About light therapy

Light therapy is used to treat certain conditions, such as seasonal affective disorder (SAD), by exposing a person to bright, artificial light. Therapy boxes or visor caps give off artificial light that mimics natural outdoor light. Also called therapeutic bright light or phototherapy, light therapy is thought to have an effect on brain chemicals that help control mood and sleep.

It’s important to know that light therapy for skin conditions, such as psoriasis, uses ultraviolet light — which is different from the light used to treat sleep and mood disorders. Ultraviolet light is typically filtered out of light therapy boxes and visors because it can damage your eyes and skin.

The researchers looked at earlier studies showing that light therapy can ease the fatigue and sleep problems associated with jet lag and shift work. They also looked at other studies suggesting that light therapy can ease fatigue and maintain quality of life in women receiving chemotherapy for breast cancer.

In this study, the researchers wanted to see if customizing the timing of light therapy could ease fatigue and improve sleep in women who had received breast cancer treatment.


About the study

The study included 21 women diagnosed with early-stage breast cancer who had completed chemotherapy, radiation therapy, or both, one to three years earlier.

All the women were having two or more of the following symptoms:

  • fatigue

  • depression

  • problems concentrating and remembering

  • problems sleeping

The women in the study had an average age of 52.8 years and had their last breast cancer treatment about two years before enrolling in the study. More than 90% of the women in the study were white.

The researchers classified the women as either morning or evening chronotypes. Chronotype is your body’s natural inclination to sleep at a certain time. It’s what most people refer to as being an early bird or a night owl. Your chronotype is the reason why you feel more alert at certain times of the day and sleepier at others.

Your chronotype is related to your circadian rhythm, which controls your daily sleep-wake cycle and causes your body to release melatonin in response to light and temperature. You can shift your circadian rhythm by sticking to a strict sleep-wake schedule, but your chronotype is more permanent.

Of the women in the study, five were evening chronotypes and 16 were morning chronotypes.

The researchers used two common tools to measure fatigue and two other standard tools to measure sleep quality and sleep disruptions. The women in the study also kept a daily sleep log.

The researchers split the women randomly into two groups:

  • 12 women were exposed to bright blue-green light through the visor cap (the experimental group)

  • nine women were exposed to dim red light through the visor cap (the control group)

The women wore the caps 30 minutes a day for 14 days.

The timing of the light therapy was based on the women’s chronotype. Evening chronotypes wore the cap within 30 minutes of waking up in the morning. Morning chronotypes wore the caps between 7 p.m. and 8 p.m.

After the researchers adjusted for the women’s baseline fatigue levels, the results showed that the severity of fatigue experienced by women in the experimental group who were exposed to bright blue-green light decreased after 14 days of light therapy.

This difference was statistically significant, which means that it was likely because of the light exposure rather than just due to chance.

Women in the control group who were exposed to dim red light also had less severe fatigue after 14 days of light therapy, but the difference wasn’t statistically significant.

The results also showed that after 14 days of light therapy, both groups had fewer sleep disturbances, better sleep quality, fell asleep faster, and slept longer.

“We know that cancer messes with patients’ circadian rhythms,” Horng-Shiuann Wu, PhD, associate professor of nursing at Michigan State University and lead author of the study, said in a statement. “My hunch is that we could reset a patient’s circadian rhythm with light therapy.

“If you are exposed to the light during the wrong time, it will make your circadian rhythm disruption worse,” she continued. “I customized the time for each patient so I can produce the effect in the right direction (going to bed earlier or later).”


What this means for you

The results of this study are promising if you’ve received treatment for early-stage breast cancer and continue to have fatigue and problems sleeping.

Bright light therapy has very few risks. But exposure to light therapy at the wrong time for your chronotype may worsen sleeping problems and fatigue, so it makes sense to ask a professional for help.

You may want to talk with your doctor about light therapy or ask for a referral to see a sleep specialist who can give you more information.

Together, you can decide if light therapy is a good fit for your unique situation.

Written by: Jamie DePolo, senior editor

— Last updated on July 14, 2022, 4:43 PM

Reviewed by 1 medical adviser
Brian Wojciechowski, MD
Crozer Health System, Philadelphia area, PA
Learn more about our advisory board
Share your feedback
Help us learn how we can improve our research news coverage.