Author(s): SENDRA-PÉREZ, C., APARICIO-APARICIO, I., OFICIAL-CASADO, F., REBOLLAR-CUENCA, E., GALINDO, C., HERMO-ARGIBAY, A., CIBRIÁN ORTIZ DE ANDA, R.M., PRIEGO-QUESADA, J.I., Institution: UNIVERSITY OF VALENCIA, Country: SPAIN, Abstract-ID: 2709

INTRODUCTION:
Monitoring skin perfusion is of growing interest in sports science as a potential indicator of internal load and recovery [1]. Exercise induces prolonged vasodilation and peripheral blood pooling, which can persist for hours, influencing post-exercise hypotension and recovery processes like plasma volume restoration. While Laser Doppler Perfusion Imaging offers non-contact, high-resolution mapping of microcirculatory perfusion, its application in exercise contexts is limited by long scanning times [2]. This study aimed to identify the most sensitive regions of interest in the lower limbs to evaluate skin perfusion responses five hours after running in warm conditions.
METHODS:
22 participants (17 males and 5 females) were included in the study, divided into an exercise group (EG, n=11) and a control group (CG, n=11). The EG performed a 50-min outdoor run at moderate intensity in warm temperatures (28–31°C), while the CG remained at rest. Measurements were taken before and five hours post-exercise in a controlled indoor environment (26°C). Skin perfusion was assessed using moorLDI2 device across six regions: anterior/posterior thigh, knee, and leg. For the Δ values of skin perfusion, Friedman test with Mann-Whitney U post-hocs with Bonferroni correction was applied. For significant pair differences, Hedge’s effect sizes (ES) were computed and classified as small (ES 0.2–0.5), moderate (ES 0.5–0.8), or large (ES>0.8).
RESULTS:
The exercise group showed a significantly higher increase in skin perfusion compared to the control group in three specific regions: the anterior thigh (95%CI[7, 58%], p=0.02 and ES=1.0), the anterior leg (95%CI[1, 79%], p=0.04 and ES=0.3), and the posterior thigh (95%CI[8, 56%], p<0.01 and ES=0.5). Conversely, the posterior leg exhibited high perfusion increases in both groups, suggesting a stronger influence of circadian rhythms or anatomical factors rather than exercise in this specific area.
CONCLUSION:
The pronounced perfusion response in the anterior thigh is likely due to the high metabolic heat production from the quadriceps during running and the subsequent thermoregulatory demand for heat dissipation. The persistence of these changes five hours later suggests mechanisms beyond acute thermoregulation, such as sustained nitric oxide bioavailability or local inflammatory processes. These findings indicate that the anterior thigh is the most effective region for monitoring skin perfusion related to exercise internal load in warm environments. Focusing on this region can optimize Laser Doppler Perfusion Imaging protocols by reducing scanning times while maintaining physiological relevance for athletes.

1. Girkantaite et al. (2022)
2. Carrión-González et al. (2025)

Funding: This work is part of the project PID2023-152125NA-I00 funded by the Spanish Ministry of Science and Innovation through the State Research Agency and FEDER (European Union) and the CIPROM/2021/64 funded by Generalita Valenciana, Spain.