3.2. Skin Peripheral Blood Flow and Temperature Profiles upon Cold-Stimulated Stress
COLD
During the screening, the baseline autonomic and subjective responses of the participants for finger skin blood flow and temperature did not differ in the cold-stimulate stress tests. The skin peripheral blood flow and temperature profiles of the study subjects just before the cold-stimulate stress are presented in The box plot of median and mean values (diamond shape) of profiles revealed that the finger skin temperature did not differ (30.3 ± 4.0, 30.6 ± 4.3, and 30.4 ± 3.8 °C after ingestion of either a high dose or a low dose of the HEPT7G/βCD inclusion complex, or placebo, respectively) just before immersion of the hand into a cold water tub maintained at 15 ± 2 °C (Furthermore, the measured finger skin blood flow, conducted during the described set of experiments, showed an effective increasing pattern during the rewarming after the ingestion of both HEPT7G/βCD doses compared to the placebo. There was a significant increase in blood flow, which led to a relatively effective recovery of skin temperature. With placebo intake, the finger skin blood flow remained lower after a brief period of temporary increase. On the other hand, the variation in the time delay of an increase in blood flow during rewarming was prominent in high-dose intake compared to low-dose. A non-parametric Friedman rank test with repeated measures revealed a significant overall difference in finger skin blood flow among the three treatments [χThe finger skin temperature before the intake of either varied doses of HEPT7G/βCD inclusion complex or placebo was almost in the constant range of temperature (31.5 °C to 35.7 °C), reflecting the different individual biological responses to the ambient environment, and was not statistically significant. Upon immersion into cold water (15 ± 2 °C), the dynamic responses of the finger skin temperature were unaltered during the exposure to cold stress, and the finger skin temperature decreased, regardless of treatments or placebo intakes. After the withdrawal from cold stress, during the rewarming (recovery) period, a gradual increase in the finger skin temperature was recorded for placebo as well as for HEPT7G/βCD inclusion complex consumptions. For placebo intake, after a brief period of quick recovery of finger skin temperature, the rate of rewarming was comparatively slower than low-dose consumption of the HEPT7G/βCD inclusion complex. Meanwhile, the rewarming was somewhat reduced with high-dose HEPT7G/βCD inclusion complex ingestion without negatively affecting the finger skin blood flow (The result of the non-parametric Friedman rank test with repeated measures indicated a significant overall difference in rewarming efficacy in finger skin temperature among the three treatments (χThe Spearman correlation analysis was conducted to examine the relationship between skin temperature and peripheral blood flow (Further, no sequence effects of the respective high and low doses of HEPT7G/βCD inclusion complex and placebo consumption on peripheral skin blood flow (mL/min) and skin temperature (°C) were noticed between the geometric mean of the three groups after the randomization during the study period. A non-parametric Friedman rank test with repeated measures revealed a significant overall difference for all three groups in both skin blood flow (