Supplementary Material for: Investigation of an Immediate Effect of Bright Light on Oxygen Consumption, Heart Rate, Cortisol, and α-Amylase in Seasonal Affective Disorder Subjects and Healthy Controls

Background: Body (fat) mass has been shown to decrease following bright light treatment for overweight women, irrespective of their seasonal (light) dependence. It is not known if this is due to an (immediate) increase of metabolism. Methods: Ten women with seasonal affective disorder (SAD) and 10 non-SAD women matched by age, body mass index, and menopausal status participated in a laboratory study in the morning, twice within 1-5 days. During one session, bright light (4,300 lx) was presented for 30 min, and during the other session, red light (250 lx “placebo”) was used. After an initial 15 min of sitting quietly in an experimental chamber, 10-min measurements were done before, at the end, and 15 min after light exposure; the subjects remained seated for 80 min in total. The measurements included 5-min oxyspirography (oxygen consumption, carbon dioxide emission, and heart rate), saliva sampling for the estimation of cortisol and α-amylase concentrations, and self-rating of mood, energy, and sleepiness. Results: There was no light-specific effect on the measured variables, except that sleepiness was reduced more with bright light than with red light in the combined group. α-Amylase values were lower in the SAD patients than in the non-SAD controls. Conclusions: Morning artificial bright light, in comparison with dim red light, had no immediate effect on metabolism and resting sympathetic tone, though subjective sleepiness decreased more with bright light. SAD patients have low salivary α-amylase levels, indicating lower sympathetic tone.**研究背景**：已有研究证实，超重女性接受强光照射后体（脂）质量会出现下降，且该效应与其季节性光照依赖程度无关。目前尚不明确这一现象是否由代谢的即刻升高所介导。 **研究方法**：本项实验室晨间研究共纳入20名女性受试者，其中季节性情感障碍（Seasonal Affective Disorder, SAD）患者10名，非SAD对照女性10名，两组按年龄、体质指数（Body Mass Index, BMI）及绝经状态进行1:1匹配。所有受试者需在1~5天内完成两次实验。其中一次实验中，受试者接受时长30分钟的强光（4300勒克斯，lx）照射；另一次实验则采用250勒克斯的红光作为“安慰剂”对照。实验流程如下：受试者先在实验舱内安静静坐15分钟，随后于光照暴露前、光照结束时及光照结束后15分钟分别开展10分钟的检测；整个实验期间受试者总计静坐时长为80分钟。检测项目包括：持续5分钟的氧呼吸描记法（oxyspirography，用于检测耗氧量、二氧化碳排放量及心率）、采集唾液样本以评估皮质醇与α-淀粉酶浓度，以及对情绪、精力与嗜睡程度进行主观自评。 **研究结果**：综合两组受试者数据进行分析后发现，除嗜睡程度在强光照射下的改善幅度显著优于红光照射外，其余所有检测指标均未表现出光照特异性差异。此外，季节性情感障碍患者的唾液α-淀粉酶水平显著低于非SAD对照组。 **研究结论**：与低照度红光相比，晨间人工强光照射并未对受试者的代谢水平及静息交感神经张力产生即刻影响，但主观嗜睡程度的改善在强光照射组更为显著。季节性情感障碍患者唾液α-淀粉酶水平偏低，提示其交感神经张力处于较低水平。