Effects of acute bouts of exercise and aerobic fitness on static balance in older adults

Background Falls are a major health concern in older adults and are closely linked to impaired balance. While regular physical activity improves health and helps prevent falls, acute bouts of exercise can transiently impair postural control. These exertion-related balance deficits have been linked to elevated lactate levels, which, in the context of physical exertion, may indicate insufficient oxygen delivery to working muscles. As aerobic fitness declines with age, older adults may be especially vulnerable to such impairments. This study aims to examine the effects of physical exertion on balance in older adults (1), assess whether aerobic fitness modulates post-exercise balance impairments (2), and explore group differences based on fall history (3). Methods Overall, 105 community-dwelling older adults were enrolled (50, no fall history; 55, with fall history). Participants attended three laboratory visits, involving cardiopulmonary exercise testing to assess aerobic fitness and cardiorespiratory adaptability, and static balance assessments using inertial measurement units. Sway parameters were evaluated before and after treadmill exercise at or above the first ventilatory threshold (VT 1 ). Mixed-model repeated-measures ANOVAs were used to test for group and condition effects. Results Exercise at the level of VT 1 significantly increased postural sway across multiple parameters, indicating a temporary deterioration of balance ( p < 0.001 for sway area, sway range, RMS sway and sway path length). Aerobic fitness markers were not significantly associated with the magnitude of the immediate exercise-induced change in postural sway although heart rate adaptability was associated with better balance performance both before and after exercise exceeding the VT 1 ( p < 0.05 for eight out of ten sway parameters). No overall group differences were observed in postural sway or aerobic fitness markers. Participants with and without a fall history did not differ in overall postural sway or aerobic fitness, but showed different postural response patterns across the subsequent measurements. Conclusions The observed increase in postural sway following exercise may indicate a transient period of reduced balance stability, although its implications for actual fall risk immediately after exertion remain uncertain. The findings suggest that cardiovascular adaptability may be associated with balance regulation. Future studies should include more heterogeneous study populations to better capture variability in aerobic fitness and functional outcomes. Trial registration The local ethics committee approved the use of the experimental procedures (No. 2021–026), and the study was registered at the German Clinical Trials Register (DRKS00024890, date of registration: 28 January 2022).