Exposure to near-infrared light before bed linked to better sleep, daytime function

Key takeaways:

• Thirty adults were randomized to wear near-infrared light-emitting cervical collar or sham device every other night for 5 weeks.
• Patients with NIR collar self-reported improvement in sleep-related symptoms.

INDIANAPOLIS — Transdermal exposure to near-infrared light before bed via a wearable device was linked to improved sleep, relaxation and next-day functionality compared with sham, according to research presented at SLEEP 2023.

“Given the emerging field of photobiomodulation and its potential neuroprotective and vasodilating effects, this red-light and near-infrared emitting device may be useful if milliwatt power level, dosage and frequency of use are refined,” Kathryn E.R. Kennedy, BS, lead study author and PhD candidate in the department of psychiatry at the University of Arizona, said in a related release.

Noting therapeutic effects, such as relaxation, with delivery of transdermal near-infrared (NIR) light, Kennedy and colleagues examined the effects of NIR exposure on sleep and daytime functioning when given before bed.

Their randomized, sham-controlled, 5-week study included 30 individuals, aged 30 to 60 years, who self-reported complaints about sleep but were not diagnosed with a sleep disorder. Following a 2-week baseline period, participants wore a NIR-emitting cervical collar (combined 660 nm, 740 nm, 810 nm and 870 nm) or sham device every other night before bed for 3 weeks.

Researchers assessed physical symptoms and sleep-related experiences using the Systematic Assessment of Treatment Emergent Effects (SAFTEE) questionnaire. They also examined differences between groups with the Insomnia Severity Index (ISI), daily sleep diaries, Oura rings and daily participant ratings of sleep quality and feeling refreshed, daytime function, energy levels, relaxation and performance.

According to results, significant differences between active and sham groups were reported in SAFTEE total score (–9.4 vs. +13.8) and sleep-related symptoms (–2.9 vs. +4.1), while no differences were reported in ISI scores, Oura recordings or sleep diary data.

While most changes were consistent between groups, the active group had decreased sleep latency (–6 mins) and REM% (–0.9%), increased average sleep quality (+0.6 pts) and feeling refreshed (+0.7 pts), and perceived increase in relaxation (17.5 pts) and daytime function (17.5 pts). Conversely, the sham group had decreases in perceived overall performance (18.7 pts) and energy level (26 pts).

“This novel phototherapy device — while still being explored and in need of further research — appeared to be generally well-tolerated by a small group of participants,” Kennedy said in the release. “Those with active, light-emitting devices — as opposed to the inert sham devices — self-reported an increase in relaxation and better sleep with use.”

Reference:

• Phototherapy device has potential to be a novel treatment for sleep complaints. https://www.sleepmeeting.org/phototherapy-device-potential-novel-treatment-sleep-complaints/. Published May 30, 2023. Accessed May 6, 2023.