Source of Support: None, Conflict of Interest: None
The effect of temperature and humidity was studied in 60 patients of bronchial asthma and 25 normal subjects. Four sets of variables were tested in each subject. 1. Cold and dry air, 2. Cold and humid air, 3. Warm and dry air and 4. Warm and humid air inhalation, The average fall in Peak Expiratory Flow Rate (PEFR) with cold dry air inhalation was 11.24 per cent and with cold humid air 3.52 per cent. Warm dry air produced a fall of 3.48 per cent, but warm humid air inhalations registered an increase in PEFR of 1.82 per cent. All these changes were statistically significant. PEFR also decreased with cold dry and improved with warm humid air inhalations. No Significant change was observed in control subjects. It was concluded that low temperature and low humidity in inspired air adversely affect the pulmonary functions in bronchial asthma patients and is related to cold stress.