The term "basking in the sun’s warmth" mentioned here literally means lying with your back toward the sun, which today we call "sunbathing." China’s great Tang poet Bai Juyi greatly valued this health-preserving practice, practicing it diligently and reaping its benefits. In his poem *Fuguo Dongri*, he joyfully described his physical and mental experience during winter sunbathing: "Sitting with closed eyes, basking in the sun, warmth spreads through the skin. Initially like drinking fine wine, then like a hibernating creature awakening. Externally, every limb feels relaxed; internally, thoughts are clear and tranquil. Boundless and free, forgetting one’s location, the heart merges with emptiness." Indeed, his reaching age 74 was likely significantly due to his regular winter sunbathing. Traditional Chinese medicine places great importance on the health benefits of sunlight, believing that regular sun exposure helps activate the body’s yang energy, especially in winter when nature is in a state of "yin dominance, yang decline." Humans, following nature, similarly benefit from increased yang energy and improved meridian circulation. The *Huangdi Neijing Suwen: Diqu Diaoshen Dala Lun* states: "In winter, the three months are for storage, ice covers the ground, and one should stay up late and rise early, waiting for the sunlight." This emphasizes aligning human sleep patterns with the sun’s cycle. Cao Cishan’s *Laolaohengyan* further explains: "Sitting with your back to the sun, as mentioned in Liezi as 'basking in the sun’s warmth,' allows the spine to receive gentle warmth, making the entire body feel comfortable. The sun is the essence of heaven, and its light strengthens yang energy." This highlights the importance of facing away from the sun, likely because the head is the convergence point of all yang energies, and direct exposure could overstimulate yang, violating the principle of yin-yang balance. Adults should regularly bask in the sun, and children equally need it. In *Qianjin Yaofang*, Sun Simiao of the Tang Dynasty wrote: "Whenever the weather is warm and windless, let mothers take their children outdoors to play in the sun. Frequent exposure to wind and sunlight makes the blood firm, muscles strong, resistant to cold and wind, and prevents illness." This clearly outlines the importance of sunbathing for children in preventing disease and promoting healthy growth. Sunlight mainly consists of ultraviolet rays, infrared rays, and visible light. Among these, ultraviolet rays have the greatest impact on the human body. Although invisible to the eye, they kill bacteria on the skin, increase skin elasticity, brightness, and softness, strengthen skin resistance, stimulate hematopoietic function, boost immunity, improve carbohydrate metabolism, promote calcium and phosphorus metabolism, and facilitate vitamin D synthesis, effectively preventing rickets or osteomalacia. They also promote blood circulation, enhance appetite, and strengthen the body. Infrared rays, though invisible, account for 60–70% of sunlight and penetrate deeply into subcutaneous tissues, exerting a warming effect that dilates blood vessels, accelerates blood flow, boosts metabolism, and provides anti-inflammatory and pain-relieving effects. Visible light, which humans can see, consists of seven colors—red, orange, yellow, green, cyan, blue, and violet—and can regulate mood, invigorate spirits, improve life enjoyment and work efficiency, and enhance various physiological functions. When sunbathing, avoid excessive exposure to prevent premature skin aging or even skin cancer caused by overexposure to UV radiation. Protect the head and eyes during sunbathing to avoid dizziness, blurred vision, or fatigue. Avoid sunbathing when hungry, full, or fatigued to prevent adverse reactions. Individuals with severe heart disease, hypertension, or neurological excitement, those allergic to sunlight, those with bleeding tendencies, and women during menstruation or within one month postpartum should also avoid prolonged sun exposure to prevent complications.
,Chăm sóc sức khỏe bằng y học cổ truyền,phương thuốc dân gian, toàn tập phương thuốc dân gian" />