Ramadan fasting and circadian ambulatory blood pressure patterns in adults aged ≥ 80 years

BACKGROUND: Ramadan fasting involves prolonged daytime abstinence from food and fluid intake and may influence cardiovascular and physiological regulation. Although prior studies have examined metabolic and cardiovascular effects, evidence on ambulatory blood pressure patterns and geriatric outcomes in the "oldest old" remains limited. OBJECTIVE: To evaluate the effects of Ramadan fasting on ambulatory blood pressure, hydration status, mobility, and fall risk in community-dwelling adults aged ≥ 80 years. METHODS: In this prospective within-subject repeated-measures study, 69 adults aged ≥ 80 years were evaluated during both fasting and non-fasting periods. Twenty-four-hour ambulatory blood pressure monitoring (ABPM) was performed using a validated automated device. Hydration status was assessed using serum and urine osmolality and the Dehydration Screening Tool. Functional and geriatric outcomes were evaluated using the Katz Activities of Daily Living scale, Timed Up and Go test, Five-Times Sit-to-Stand test, and the Itaki Fall Risk Scale. Paired comparisons were conducted between periods, and linear mixed-effects regression models were used to assess hourly blood pressure patterns. RESULTS: Mean 24-hour systolic and diastolic blood pressure demonstrated small but statistically significant increases during fasting compared with the non-fasting period (132.5 ± 16.1 vs. 129.8 ± 14.8 mmHg, p = 0.049; and 70.2 ± 9.6 vs. 68.0 ± 8.7 mmHg, p = 0.008, respectively). Hydration parameters and functional mobility did not differ significantly between periods. However, fall risk scores were significantly higher during fasting (mean difference 0.44 points; Cohen's dz = 0.52; p < 0.001). Mixed-effects analyses demonstrated significant circadian variation in blood pressure, with the greatest divergence between fasting and non-fasting conditions observed in the afternoon (approximately 15:00). CONCLUSION: In adults aged ≥ 80 years, Ramadan fasting was associated with small effect-size increases in ambulatory blood pressure and a moderate effect-size increase in fall risk, without significant changes in hydration status, or mobility. These findings suggest that fasting may be tolerated in selected very elderly individuals; however, individualized clinical assessment, blood pressure monitoring, and fall risk evaluation should be considered in primary care settings.