The effects of fasting on physiological parameters, physical fitness, and psychological wellness

Importance: Fasting impacts physiological and psychological responses, which may impact physical fitness and overall well-being of individuals. Objective: This study aims to examine the effects of fasting on physical fitness, physiological parameters, and psychological well-being among college male Muslim students. Design: A quasi-experimental repeated measures design was used, with three assessment phases: before, during, and after Ramadan. Participants: Fourteen healthy male Muslim college students (mean age: 23.1 ± 3.7 years). Interventions: Fasting is the conscious abstention from food and drinks for a certain period or designated time. Pre-Ramadan fasting is a period where participants had no time restriction to food consumption, while mid-Ramadan was the period participants abstained from food consumption from sunrise till sunset for 30 consecutive days, and post-Ramadan is the period where they return to normal diet with no time restriction. Participants were assessed in a university human performance lab at three-time phases: pre-Ramadan (one week before), mid-Ramadan (third week), and post-Ramadan (one week after). Methods: Data collection included body composition (BIA, BodPod), cardiovascular fitness (Ebbeling treadmill test to estimate VO2max), muscular strength (hand grip), flexibility (sit-and-reach), balance (single-leg stand), physical activity (GPAQ), blood lipids (total cholesterol, LDL, HDL, FBG) and psychological distress (Kessler psychological scale). Data were analyzed using repeated measures ANOVA and correlation (SPSS v29; α = 0.05). Result: Body Composition & Anthropometrics: No statistically significant changes in body mass, BMI, waist/hip, body fat percent (BIA/BodPod), fat-free mass, or waist-to-hip ratio (p >0.05) There was a significant negative correlation between change in sedentary time and body fat percentage r = –.690, p = .006. Physiological: Systolic blood pressure, diastolic blood pressure, and resting heart rate did not change over time (p >0.05), while fasting blood glucose and HDL cholesterol improved significantly (p0.05). Psychological: Kessler K6 and Distress scale showed consistently low levels across all phases, with no significant time effects (p >0.05). Conclusion: The improvement in VO2max during the beginning of Ramadan fasting was attenuated by the end of Ramadan, while there was some improvement in blood glucose and HDL cholesterol. These results support the safety and potential physiological advantages of Ramadan fasting and fasting at large in healthy adults. Relevance: This study adds to the body of evidence that Ramadan fasting enhances physiological health and promotes cardiometabolic benefits without compromising mental or physical performance in healthy adult. The findings also contribute to broader research showing that structured fasting such as Ramadan, intermittent, or other types of fasting may be a healthy practice that aids in support of diverse populations. This abstract was presented at the American Physiology Summit 2026 and is only available in HTML format. There is no downloadable file or PDF version. The Physiology editorial board was not involved in the peer review process.