Health & Wellness | 健康知识库

by 大牙哥

利用光线（阳光、蓝光与红光）优化健康

Using Light (Sunlight, Blue Light & Red Light) to Optimize Health

16分钟阅读

利用光线（日光、蓝光与红光）优化健康

摘要

光是现有最强大、最精准的生物工具之一，能够改变基因表达、激素水平、睡眠、情绪、痛觉耐受及细胞功能。不同波长的光能穿透组织至不同深度，并被特定细胞器吸收，从而产生靶向生物效应。本期内容涵盖光对人体生理机能影响的作用机制，并提供利用日光、红光及紫外线优化健康的可操作方案。

核心要点

  • 清晨直接接受日光照射，让光线直达眼睛（不通过窗户或太阳镜），以调节褪黑素、皮质醇及昼夜节律
  • 避免在约晚上10点至凌晨4点之间接受强光照射——即便是夜间短暂的强光也会使褪黑素水平骤降至接近零
  • 红色或琥珀色的昏暗光线因波长较长，对褪黑素的抑制极为有限，是夜间使用的更安全选择
  • UVB皮肤照射（每次20–30分钟，每周2–3次，尽量减少遮蔽衣物）可显著提升睾酮和雌激素水平，并改善情绪与性欲
  • 红光疗法（每次1–3分钟，在一天早些时候进行，每周数次）可通过促进视网膜细胞的ATP生成，来延缓与年龄相关的视力衰退
  • 蓝光阻断眼镜应仅在傍晚或夜间佩戴——白天佩戴会阻挡有益的UVB及短波长光线
  • 褪黑素补剂的剂量通常超出生理需要，且会干扰内源性褪黑素的自然季节性节律；使用时应谨慎
  • 皮肤和眼睛接受UVB光照射，均可通过导水管周围灰质区激活内源性阿片（镇痛）通路
  • 即便在阴天，户外光线所提供的有益光子也远多于室内人工照明

详细笔记

光的物理学基础

  • 光是以波的形式传播的电磁能量，被吸收后可改变生物过程
  • 可见光谱（从红色到紫色）只是所有光波长的一部分；紫外线（UV）和红外线虽对人类不可见，同样会影响生物机能
  • 波长决定组织穿透深度：
    • 短波长（紫外线、蓝光、绿光）：仅穿透皮肤表层
    • 长波长（红光、近红外线）：可深度穿透组织——穿过皮肤，甚至可能到达骨髓
  • 不同波长的光被特定细胞器（如线粒体、细胞核）优先吸收，从而实现靶向细胞效应

光如何转化为生物信号

三种主要机制：

  1. 眼睛中的感光细胞——视杆细胞（对广泛波长敏感）和视锥细胞（通过光色素对红/绿/蓝光调谐）
  2. 皮肤中的黑色素细胞——吸收紫外线，触发色素沉着（晒黑）及更深层的生物级联反应
  3. 全身每一个细胞——若光线能直接或间接到达某细胞，即会改变该细胞的功能；大多数内脏器官通过眼睛和皮肤发出的激素或神经信号间接接收光信号

光、褪黑素与昼夜/季节节律

  • 视网膜中的内在光敏黑视素神经节细胞吸收短波长光，并向松果体发出信号以抑制褪黑素分泌
  • 冬季： 夜晚更长 → 褪黑素持续时间更长 → 睾酮/雌激素水平更低
  • 夏季： 夜晚更短 → 褪黑素持续时间更短 → 性激素分泌水平更高
  • 内源性褪黑素具有两项功能：
    • 调节功能： 增加骨量（通过成骨细胞）、在童年期抑制性腺发育、调节睡眠/觉醒周期
    • 保护功能： 强效抗氧化剂；激活免疫；可能具有抗癌特性
  • 给褪黑素带来保护效应的，是其节律性的升降——而非长期维持高水平的褪黑素

实操方案：夜间保护褪黑素

  • 避免在约晚上10点至凌晨4点之间使用明亮的顶部照明
  • 若必须在夜间使用光源，请选用昏暗的红色或琥珀色光（长波长 = 对褪黑素抑制最小）
  • 倒班工人应遮蔽睡眠环境，并在睡眠期间尽量减少光照

UVB光、激素与交配行为

基于2021年发表于 Cell Reports 的研究：“Skin Exposure to UVB Light Induces a Skin-Brain-Gonad Axis and Sexual Behavior”

主要发现（小鼠与人类）：

  • UVB皮肤照射使两性的睾酮、雌二醇和孕酮水平均有所提升
  • 增强了对女性吸引力的感知，并提高了两性对交配的接受度
  • 促进了女性的卵泡成熟（生育力指标）
  • 使小鼠睾丸和卵巢体积增大
  • 来自低紫外线暴露国家或肤色较浅的个体，睾酮增幅更大（肤色较深者皮肤中有更多黑色素细胞，会在UV激活p53通路之前吸收/阻挡更多紫外线）
  • 激素水平与季节相关：冬季（1月至3月）最低，夏季（6月至9月）最高

机制：

  • UVB激活皮肤角质形成细胞中的 p53 → 触发下游激素水平升高
  • 这是一条直接的皮肤通路，与眼睛-褪黑素通路相互独立
  • 在基因敲除小鼠中去除皮肤p53后，激素效应消失

方案：通过日光照射优化激素与情绪

  • 时长： 每次20–30分钟
  • 频率： 每周2–3次
  • 着装： 短袖、短裤或短裙（不戴帽子，不戴太阳镜）；遵循文化习俗
  • 总疗程： 10–12次（约1个月）
  • 防晒霜会减少UVB吸收；需结合个人情况权衡皮肤癌风险与获益
  • 窗玻璃和汽车挡风玻璃会阻挡UVB——户外暴露不可替代

UVB光与镇痛

已确定两条通路：

  1. 皮肤通路： UVB照射皮肤触发β-内啡肽（内源性阿片类物质）和促肾上腺皮质激素的释放，提高全身痛觉耐受

  2. 眼睛通路（来自2022年发表于 Neuron 的研究：“A Visual Circuit Related to the Periaqueductal Gray Area for the Antinociceptive Effects of Bright Light Treatment”）：

    • 视网膜中的黑视素细胞捕获短波长光
    • 信号传至腹侧外膝体 → 导水管周围灰质（PAG）
    • PAG释放内源性阿片类物质（β-脑啡肽、脑啡肽、mu阿片受体配体）
    • 结果：痛觉（疼痛感知）减弱

慢性疼痛方案：

  • 同样适用上述20–30分钟、每周2–3次的日光照射方案
  • 同时让皮肤和眼睛都接受光照，以获得最大效益
  • 在高紫外线地区，需谨慎使用防晒霜并注意紫外线强度

红光疗法与视力

基于伦敦大学学院 Dr. Glen Jeffery 实验室的研究：

  • 在一天早些时候进行短暂的红光照射（每次1–3分钟，每周数次），可延缓40岁以上人群与年龄相关的视力衰退
  • 机制：视网膜感光细胞代谢极为旺盛；衰老会降低其ATP生成效率；红光可补充线粒体的ATP生成能力
  • 时机至关重要： 必须在一天早些时候进行才有效
  • 这是长波长光直接作用于特定细胞类型线粒体的典型案例

蓝光阻断眼镜：何时使用（以及何时不用）

  • 白天避免佩戴： 蓝光阻断眼镜会过滤短波长光，而这些光对昼夜节律的校正、激素刺激以及通过眼睛实现的镇痛效果至关重要
  • 适宜使用的时机： 若难以入睡或睡眠维持困难，可在傍晚和夜间佩戴
  • 进行清晨光照方案时，请勿佩戴

相关概念

  • circadian rhythm
  • melatonin
  • intrinsically photosensitive retinal ganglion cells

English Original 英文原文

Using Light (Sunlight, Blue Light & Red Light) to Optimize Health

Summary

Light is one of the most powerful and precise biological tools available, capable of modifying gene expression, hormone levels, sleep, mood, pain tolerance, and cellular function. Different wavelengths of light penetrate tissues to different depths and are absorbed by specific organelles, enabling targeted biological effects. This episode covers the mechanisms behind light’s effects on human physiology and provides actionable protocols for using sunlight, red light, and UV light to optimize health.

Key Takeaways

  • Get morning sunlight exposure directly to your eyes (not through windows or sunglasses) to regulate melatonin, cortisol, and circadian rhythms
  • Avoid bright light exposure between ~10 PM and 4 AM — even brief bright light in the middle of the night can crash melatonin to near zero
  • Red or amber dim light at night minimally suppresses melatonin due to its long wavelength, making it safer for nighttime use
  • UVB skin exposure (20–30 minutes, 2–3x per week, minimum clothing) can significantly increase testosterone and estrogen, and elevate mood and sexual passion
  • Red light therapy (1–3 minutes, early in the day, a few times per week) may offset age-related vision loss by boosting ATP production in retinal cells
  • Blue blocker glasses should only be worn in the evening/night — wearing them during the day blocks beneficial UVB/short-wavelength light
  • Melatonin supplements are typically supraphysiological in dose and disrupt the natural seasonal rhythm of endogenous melatonin; use with caution
  • UVB light exposure to both the skin and the eyes activates endogenous opioid (pain-relief) pathways via the periaqueductal gray area
  • Even on overcast days, outdoor light delivers far more beneficial photons than indoor artificial lighting

Detailed Notes

Physics of Light: Foundations

  • Light is electromagnetic energy that travels in waves and can alter biological processes upon absorption
  • The visible spectrum (red → violet) is just a portion of all light wavelengths; ultraviolet (UV) and infrared light also affect biology despite being invisible to humans
  • Wavelength determines tissue penetration depth:
    • Short wavelengths (UV, blue, green): penetrate only the skin’s surface
    • Long wavelengths (red, near-infrared): penetrate deep into tissue — through skin, potentially reaching bone marrow
  • Different wavelengths are preferentially absorbed by specific organelles (e.g., mitochondria, nucleus), enabling targeted cellular effects

How Light Is Converted Into Biological Signals

Three primary mechanisms:

  1. Photoreceptors in the eye — rods (broad wavelength sensitivity) and cones (red/green/blue-tuned via photopigments)
  2. Melanocytes in the skin — absorb UV light and trigger pigmentation (tanning) and deeper biological cascades
  3. Every cell of the body — if light can reach a cell directly or indirectly, it alters that cell’s function; most internal organs receive light signals indirectly via hormonal or neural relay from the eyes and skin

Light, Melatonin, and Circadian/Seasonal Rhythms

  • Intrinsically photosensitive melanopsin ganglion cells in the retina absorb short-wavelength light and signal the pineal gland to suppress melatonin
  • Winter: longer nights → longer melatonin duration → lower testosterone/estrogen
  • Summer: shorter nights → shorter melatonin duration → higher sex hormone output
  • Endogenous melatonin has two roles:
    • Regulatory: increases bone mass (via osteoblasts), suppresses gonadal maturation during childhood, modulates sleep/wake cycles
    • Protective: potent antioxidant; immune activation; possible anti-cancer properties
  • It is the rhythmic rise and fall of melatonin — not chronically elevated melatonin — that confers its protective effects

Practical Protocol: Melatonin Preservation at Night

  • Avoid bright overhead light between ~10 PM and 4 AM
  • If you must use light at night, use dim red or amber light (long wavelength = minimal melatonin suppression)
  • Shift workers should black out sleeping environments and minimize light during their sleep cycle

UVB Light, Hormones, and Mating Behavior

Based on a 2021 Cell Reports study: “Skin Exposure to UVB Light Induces a Skin-Brain-Gonad Axis and Sexual Behavior”

Key findings (mice and humans):

  • UVB exposure to skin increased testosterone, estradiol, and progesterone in both sexes
  • Enhanced female attractiveness perception and increased receptiveness to mating in both sexes
  • Increased follicle maturation (indicator of fertility) in females
  • Increased testicular and ovarian size in mice
  • Testosterone increases were greater in individuals from low-UV-exposure countries or with paler skin (more melanocytes in darker skin absorb/block more UV before it triggers the p53 pathway)
  • Hormone levels tracked with season: lowest in winter (Jan–Mar), highest in summer (Jun–Sep)

Mechanism:

  • UVB activates p53 in skin keratinocytes → triggers downstream hormone increases
  • This is a direct skin pathway, separate from the eye-melatonin pathway
  • Removing p53 from skin in knockout mice abolished the hormonal effects

Protocol: Sunlight Exposure for Hormone and Mood Optimization

  • Duration: 20–30 minutes per session
  • Frequency: 2–3 times per week
  • Clothing: Short sleeves, shorts or skirt (no hat, no sunglasses); culturally appropriate
  • Total course: 10–12 sessions (~1 month)
  • Sunscreen will reduce UVB absorption; weigh skin cancer risk vs. benefit individually
  • Windows and car windshields block UVB — outdoor exposure is necessary

UVB Light and Pain Relief

Two pathways identified:

  1. Skin pathway: UVB to skin triggers release of beta-endorphins (endogenous opioids) and corticotropin hormone, raising systemic pain tolerance

  2. Eye pathway (from a 2022 Neuron study: “A Visual Circuit Related to the Periaqueductal Gray Area for the Antinociceptive Effects of Bright Light Treatment”):

    • Short-wavelength light captured by melanopsin cells in the retina
    • Signal travels to the ventral lateral geniculate nucleus → periaqueductal gray (PAG)
    • PAG releases endogenous opioids (beta-enkephalin, enkephalin, mu-opioid ligands)
    • Result: reduced nociception (pain perception)

Protocol for chronic pain:

  • Same 20–30 minute, 2–3x/week sunlight protocol applies
  • Get light to both skin and eyes for maximum effect
  • Caution with sunscreen and UV intensity in high-exposure climates

Red Light Therapy and Vision

Based on work from Dr. Glen Jeffery’s lab at University College London:

  • Brief red light exposure early in the day (1–3 minutes, a few times per week) can offset age-related vision loss in people 40+
  • Mechanism: retinal photoreceptors are extremely metabolically active; aging reduces their ATP production efficiency; red light replenishes mitochondrial ATP-generating capacity
  • Timing matters: must be done early in the day to be effective
  • This is a direct example of long-wavelength light accessing mitochondria in specific cell types

Blue Blockers: When to Use (and When Not To)

  • Avoid during daytime: blue blockers filter short-wavelength light that is needed for circadian entrainment, hormone stimulation, and pain relief via the eye
  • Appropriate use: evenings and nighttime if struggling with sleep onset or maintenance
  • Do not wear during morning light-viewing protocols

Mentioned Concepts

  • circadian rhythm
  • melatonin
  • intrinsically photosensitive retinal ganglion cells

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