![]() ![]() We also discuss the potential influence of the key circadian hormone melatonin on sleep and metabolic physiology. This review will highlight the complex role of light in human physiology, with a specific emphasis on metabolic regulation from the perspective of four main properties of light (intensity, duration, timing of exposure, and wavelength). Research has revealed that various properties of light influence metabolism. Disruptions to these areas due to light are linked to metabolic abnormalities such as an increased risk of obesity and diabetes. Light exposure is closely linked to sleep–wake regulation, activity and eating patterns, body temperature, and energy metabolism. The increase in light exposure at unwanted times or a reduced dynamic range of light between the daytime and nighttime has introduced negative consequences for human health. Artificial light has restructured human activity and provided opportunities to extend the day without reliance on natural day–night cycles. The natural light–dark cycle has been the dominant stimulus for circadian rhythms throughout human evolution. Light is an essential part of many life forms. To conclude, light therapy shows some effectiveness for sleep maintenance in insomnia disorders, but further research is needed to refine the light parameters to be chosen according to the type of insomnia, in the hope of developing personalised therapeutics. A light dose-response may exist but the studies' heterogeneity and publication bias limit the interpretation. No worsening was observed in objective nor subjective measures, except for TST in one study with evening exposure. Morning light exposure advanced sleep-wake rhythms and evening exposure led to a delay. ![]() Qualitative analysis of the review showed some improvement mainly in subjective measures. Meta-analysis was performed with 13 of them: light therapy for insomnia compared with control conditions significantly improved wake after sleep onset (WASO: SMD = -0.61 p = 0.017 weighted difference of 11.2 min ☑1.5 based on actigraphy, and SMD = -1.09 (p < 0.001) weighted difference of -36.4 min ☑5.05) based on sleep diary, but no other sleep measures such as sleep latency, total sleep time (TST), or sleep efficiency. Twenty-two studies with a total of 685 participants were included, five of which with a high level of proof. We conducted a systematic literature review and meta-analysis according to Cochrane and PRISMA guidelines and using the databases Medline, Cochrane, and Web of Science, with a special focus on light therapy and insomnia. Bright light therapy (LT) has proven its efficacy in circadian and mood disorders. In the management of insomnia, physicians and patients are seeking alternative therapeutics to sleeping pills, in addition to sleep hygiene and cognitive behavioural therapy.
0 Comments
Leave a Reply. |