Effect of Ramadan Fasting on Blood Pressure among Health Care Workers in a Specialized Hospital in Bangladesh

Background

 Each year, hundreds of millions of adult Muslims around the world refrain from eating and drinking during daylight hours for one month during Ramadan. The lifestyle changes in Ramadan, including intermittent dietary restriction, result in various physiological and metabolic alterations. This study aimed to assess the effect of Ramadan fasting on blood pressure.

Methods

This longitudinal study was conducted among adult Muslim healthcare workers of the National Heart Foundation Hospital and Research Institute who fasted for at least 20 days during Ramadan. Of 416 enrolled before Ramadan, 306 attended the follow-up visit immediately after Ramadan. Individuals with cardiovascular diseases, other than hypertension, and chronic kidney disease were excluded. Socio-demographic characteristics, smoking status, and medical history were collected at baseline. Blood pressure, body weight, and body water composition were measured at both visits. Blood pressure was measured three times using an automated oscillometric device, and the average of the last two readings was recorded. Body water composition was assessed using a bioelectrical impedance analyzer. Paired data, including changes in systolic and diastolic blood pressure (SBP and DBP), were analyzed using paired t-tests and Wilcoxon signed-rank test. Mixed-effects regression models were applied to assess the effect of Ramadan fasting on SBP and DBP while controlling for potential covariates. A principal component ‘body composition’ was used to avoid multicollinearity between BMI, fat mass, and body water.

Results

The mean age of the participants was 31.4±8.6 years; two-thirds (67.7%) were female. Before Ramadan, mean SBP was 104.6 mmHg (95% CI: 102.9, 106.3) and DBP was 70.0 mmHg (95% CI: 68.9, 71.1). After Ramadan, mean SBP decreased to 102.3 mmHg (95% CI: 100.8, 103.7), while DBP slightly increased to 70.4 mmHg (95% CI: 69.4, 71.3).   

In the mixed-effects regression model adjusted for age, sex, smoking and hypertension status, and body composition, the decline in SBP remained significant (-1.6 mmHg, 95% CI: -2.6, -0.5, p=0.004), while DBP showed a small but significant increase (0.9 mmHg, 95% CI: 0.2, 1.5, p=0.01). A significant interaction was observed between Ramadan fasting and hypertension status for both SBP and DBP (βSBP = −5.4, 95% CI: −9.0 to −1.8, p = 0.003; βDBP = −3.4, 95% CI: −5.9 to −0.8, p = 0.01), indicating that the effect of Ramadan fasting was more pronounced in hypertensive patients.

Conclusion

Ramadan fasting was associated with a small but significant reduction in systolic BP and a modest rise in diastolic BP. Notably, hypertensive participants experienced larger decreases in both SBP and DBP, indicating potential cardiovascular benefits of fasting for hypertensive persons.