Physiological and subjective responses to low relative humidity
Yujin Sunwoo1, Chinmei Chou, Junko Takeshita
1Department of Ergonomics, Kyushu Institute of Design, Japan. sunwooyujin@yahoo.com
Journal of Physiological Anthropology
|April 18, 2006
Summary
Low relative humidity (RH) significantly impacts eye and skin dryness, affecting saccharin clearance time (SCT) and skin temperature. Maintaining RH above 30% is crucial for ocular and skin comfort, while RH above 10% is needed for nasal comfort.
Area of Science:
- Environmental Physiology
- Dermatology
- Ophthalmology
Background:
- Relative humidity (RH) is a key environmental factor influencing human physiological responses.
- Understanding the effects of low RH on skin, eyes, and nasal passages is important for comfort and health.
Purpose of the Study:
- To investigate the physiological and subjective responses to varying low relative humidity (RH) levels.
- To determine critical RH thresholds for maintaining ocular, skin, and nasal mucosal hydration.
Main Methods:
- Healthy male subjects were exposed to controlled environments with RH levels of 10%, 30%, and 50% at a constant temperature (25°C).
- Physiological measurements included saccharin clearance time (SCT), blinking frequency, heart rate (HR), blood pressure, skin hydration, transepidermal water loss (TEWL), sebum levels, and skin temperature.
- Subjective assessments of thermal sensation, dryness, and comfort were recorded.
Main Results:
- Low RH significantly affected SCT, ocular and skin dryness, and decreased mean skin temperature.
- RH levels below 30% led to dry eyes and skin, while RH below 10% also caused nasal dryness.
- Cardiovascular responses (HR, blood pressure) and sebaceous gland activity were not affected by RH variations.
- Subjects perceived coldness more readily than dryness upon changes in RH.
Conclusions:
- Maintaining relative humidity above 30% is recommended to prevent dryness of the eyes and skin.
- Relative humidity above 10% is necessary to avoid dryness of the nasal mucous membrane.
- Environmental RH significantly influences comfort and physiological hydration, with distinct thresholds for different mucosal surfaces.
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