The effect of Ramadan fasting on spirometry in healthy subjects

Objectives:  Lung function tests are an important investigative tool in diagnosing respiratory diseases, judging their severity and assessing prognosis. The primary aim of the present study was to assess whether Ramadan fasting affected normal lung function values. Methodology:  Forty-six non-smoking healthy males, with a mean age of 24.2 years (SD 6.4 years) were investigated. Spirometry was performed according to the recommendations of the American Thoracic Society. Days between the 15th and 25th of three Islamic months (pre-Ramadan, Ramadan and post-Ramadan) were selected for spirometry. On all three occasions, FVC, FEV1, FEV1/FVC%, maximum voluntary ventilation (MVVindirect), PEF, FEF25−75% and body mass were measured. Pre- and post-Ramadan readings were compared with the readings during Ramadan fasting. The results were analysed by repeated measures analysis of variance. Results:  No significant change was seen in lung function during Ramadan as compared to the pre-Ramadan period. FVC was decreased significantly in the post-Ramadan period compared to Ramadan and this period was associated with a significant increase in body mass. Conclusion:  Relative to pre-Ramadan baseline values, there was no change in spirometry during Ramadan fasting in these subjects.