Swimming or exercising in a pool is often recommended as an ideal activity for individuals with lower limb joint disorders, especially those who are overweight. The buoyancy of water reduces the load on the lower limb joints, making aquatic exercise less likely to cause joint wear and tear, particularly beneficial for weight loss in obese individuals. Indoor pools in winter often provide hot water, making swimming a form of heat therapy. Many people also have access to hot water spas or Jacuzzi baths at home for convenient use.
The primary therapeutic mechanism of hot baths or hot springs is the transmission of heat stimulus through water to the body. This heat, combined with the massaging force of the water and the transdermal effect of certain minerals, offers significant therapeutic benefits. Water's ability to maintain and regulate heat, coupled with its full contact with the body, allows for prolonged and uniform heat stimulation. People often feel relaxed after a hot bath or soak, and localized wet heat application can aid in the recovery of certain conditions, like promoting inflammation reduction or maturation of abscesses.
However, it's important to note that aquatic therapies, like baths and swimming, have their downsides. Traditional Chinese Medicine identifies excessive moisture or humidity as "Damp Evil," a detrimental factor for chronic rheumatic pain or weakened patients. During continuous rainy days, the combination of lower temperatures, decreased air pressure, and increased humidity exacerbates rheumatic pain, with humidity playing a significant role. Humidity causes blood vessel dilation around joints and joint capsule congestion. Moreover, moisture can increase heat conduction by 20 times. When clothes are wet from rain, body heat dissipates faster, making it easier to catch a cold. Arthritis patients, in particular, may experience increased joint pain in such conditions. Observations suggest that a change of more than 3°C in average daily temperature, a variation of more than 1000Pa in daily air pressure, or a relative humidity fluctuation greater than 10% can lead to an increase in joint pain cases.
Therefore, soaking in water might not be beneficial for patients with chronic pain, especially those whose pain intensifies in humid weather or can predict rain based on joint pain. Such individuals should avoid these therapies, especially on humid days, and even limit the duration of hot showers. Those accustomed to swimming should minimize soaking time in the water and dry off quickly after swimming.
Some argue that the concepts of "Cold Evil" and "Damp Evil" from Eastern philosophy do not apply to Westerners. For example, Western women are often encouraged to drink cold water, take hot baths, and eat ice cream immediately after childbirth without apparent ill effects. However, from observations, Westerners, like Chinese, can also be affected by cold and damp external evils, experiencing an increase in rheumatic pain during cold or humid weather. The main difference might be that Westerners, typically consuming a higher-calorie, meat-based diet, may have a higher tolerance to cold compared to Chinese individuals.
In summary, while aquatic exercises and hot baths offer therapeutic benefits, particularly for overweight individuals and for general relaxation, they can also have adverse effects, especially for people with chronic pain conditions exacerbated by cold or damp conditions. This highlights the importance of a tailored approach to pain management, considering individual sensitivities and environmental factors.