Enhancement of the finger cold-induced vasodilation response with exercise training

Cold-induced vasodilatation (CIVD) is a cyclical increase in finger temperature that has been suggested to provide cryoprotective function during cold exposures. Physical fitness has been suggested as a potential factor that could affect CIVD response, possibly via central (increased cardiac output, decreased sympathetic nerve activity) and/or peripheral (increased microcirculation) cardiovascular and neural adaptations to exercise training. Therefore, the purpose of this study was to investigate the effect of endurance exercise training on the CIVD response. Eighteen healthy males trained 1 h d⁻¹ on a cycle ergometer at 50% of peak power output, 5 days week⁻¹ for 4-weeks. Pre, Mid, Post, and 10 days after the cessation of training and on separate days, subjects performed an incremental exercise test to exhaustion \( (\mathop V\limits^{ \cdot }\!\! {\text{O}}_{{2{\text{peak}}}} ), \) and a 30-min hand immersion in 8°C water to examine their CIVD response. The exercise-training regimen significantly increased \( \mathop V\limits^{ \cdot }\!\!{\text{O}}_{{2{\text{peak}}}} \) (Pre: 46.0 ± 5.9, Mid: 52.5 ± 5.7, Post: 52.1 ± 6.2, After: 52.6 ± 7.6 ml kg⁻¹ min⁻¹; P < 0.001). There was a significant increase in average finger skin temperature (Pre: 11.9 ± 2.4, After: 13.5 ± 2.5°C; P < 0.05), the number of waves (Pre: 1.1 ± 1.0, After: 1.7 ± 1.1; P < 0.001) and the thermal sensation (Pre: 1.7 ± 0.9, After: 2.5 ± 1.4; P < 0.001), after training. In conclusion, the aforementioned endurance exercise training significantly improved the finger CIVD response during cold-water hand immersion.