Physical activity seems to condition reactive hyperaemia reflexes in healthy individuals

Our research has shown that responses to reactive hyperemia (RH) and post-occlusive reactive hyperaemia (PORH) involve multiple reflexes, different sensors integrated centres, and effectors. Therefore, PORH responses do not solely represent local vascular adaptations. In this direction, this study was designed to explore the impact of post-occlusive reactive hyperemia (PORH) on perfusion dynamics across all extremities, including the upper contralateral and both lower limbs, in a healthy population of different ages. We hypothesized that, as so many other physiological reflexes, RH might be influenced by individual factors such as age and physical activity. A convenience sample of sixteen healthy participants aged 18 to 72 years was categorized into regular and irregular physical activity in line with WHO guidelines. PORH was evoked in one randomly chosen arm using a suprasystolic occlusion protocol. Perfusion responses were assessed by laser Doppler flowmetry (LDF) with probes placed on the palmar aspect of index fingers in both hands and the hallux on both feet. Polarized spectroscopy (TiVi) was also employed to complement perfusion measurements and provide a more comprehensive evaluation of skin microcirculatory changes. Measurements took place during three phases (1) baseline for 10 minutes (2) 200 mmHg occlusion, held for 2 minutes and (3) recovery after pressure release for 10 minutes. Our findings showed that PORH evokes a consistent similar response in the contralateral arm and lower limbs’ perfusions, confirming the reflex nature of these responses. Furthermore, we noted that participants reporting regular physical activity exhibited stronger and more sustained perfusion responses to occlusion-reperfusion in all territories compared those reporting irregular physical activity, regardless age. These findings reinforce our previous views regarding the complex global adaptive processes involved in RH. Although recognizing its preliminary nature, these results also underscore the role of physical activity in modulating vascular reflexes and systemic circulatory responses in the absence of disease and independent of age, which should be further investigated. FCT—Foundation for Science and Technology, I.P. (Portugal) [UIDB/04567/2020] and [UIDP/04567/2020] programs. All imaging instrumentation provided by ALIES-COFAC. This abstract was presented at the American Physiology Summit 2025 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.