[Objective] Physical exercises raise more or less body temperature. A body temperature is regulated constantly generally by homeostasis mechanism. Perspiration is only heat radiation mechanism under high temperature environments. And sudoriferous water is supplied from blood. Blood flow is determined by blood fluidity, blood volume and the cardiovascular system. It was reported that strong stress decreased blood fluidity. In this experiment, we investigated the relation between blood fluidity and water supply in rats loaded with forced exercise in high temperature environment. [Methods] SPF male Wistar rats weighing 150 g were used. All animals were put in high temperature environment (Wet Bulb Globe Temperature; WBGT: 28°C) through whole experimental period. In a group of water supply, distilled water was served before and later exercise by sonde forcibly. The rats were divided into five groups randomly; Rest-Non water intake (RN), Rest-Water intake (RW), Exercise-Non water intake (EN), Exercise-Water intake (EW) and Baseline (B). The blood was collected before or later of exercise and blood fluidity or platelet aggregation was measured. [Results] In the EN, platelet aggregation, lactic acid and corticosterone increased while blood fluidity were decreased significantly compared with the RN, RW and EW. In addition, the hematocrit did not increase even if water equivalent to 8 % of body weight lost it. [Conclusion] We speculate that exercise in high temperature environment decreases blood fluidity. However, the water supply that does not completely make up for quantity of depletion in exercise may improve blood fluidity.
Measuring the bioelectrical impedance (BI) is a simple and non-invasive method for estimating body fat or muscle mass. However, body impedance is affected by variations in the distribution of body fluid without reference to actual body fat or muscle mass. Twenty healthy college students (10 males, 10 females; mean age 21.0±2.3 years) participated in the study. Their mean body mass index was 20.7±2.6 kg/m2. Bipolar electrodes were place on all extremities, and InBody 3.0TM (Biospace Co., Ltd., Seoul, Korea) was used to measure bioelectrical impedance. Each subject remained in a supine position on a comfortable bed between 07:00 and 12:00 except for excretion and measurement of BI. BI was measured hourly using frequencies ranging from 5 to 500 kHz. The subjects refrained from eating, drinking and exercising between 07:00 and 12:00 during the first week of measurements, and drank 6.7 ml/kg of water at 07:00 after the first measurement of BI during a subsequent week of measurements. Bioelectrical impedance was higher in female subjects in all body segments and conditions (p<0.01). BI in the right arm was lower than that in the left in all participants (p<0.001). The difference between the highest and lowest BI among six measurements was largest in the upper extremities, followed by the lower extremities. Differences in the coefficient of variation CV values of the right arm of both females and males at 50, 250, and 500 kHz during fasting were significantly smaller than after drinking water. Hydration had no effect on the differences in the CV values of the body trunk and lower extremity BI or BI at lower frequencies. BI indicates the possibility of remarkable decrease in variation in the upper extremity BI at higher frequencies by taking 6.7 ml/kg of water at get up and enables minimizing the estimate error of body fat percentage.
The decrease of muscle glycogen may be useful for the improvement of endurance performance. Intense anaerobic exercise requires a high rate of glycogen utilization, but consecutive intense anaerobic exercises induce a pronounced decline of external power and muscle glycogen consumption. We hypothesized that a long rest period between consecutive intense anaerobic exercises may aid in sustaining external power and glycogen consumption. Secondly, we hypothesized that active rest (AR) during the long resting period may be more effective than passive rest (PR). Six subjects performed four 30-second Wingate tests (WAnT) with a 4-minute recovery between each bout (Consecutive method). The subjects also performed a similar exercise procedure, but with a 30-minute seated resting period after the second bout (PR method). The other six male subjects performed four 30-second WAnTs with a 4-minute recovery between each bout, with 30-minutes of cycling at 40% VO2max after the second bout (AR method). The subjects also performed PR method. The total work during the third and fourth bouts was greatest under the AR condition, followed by the PR condition, and finally the Consecutive method (p<0.05 for all comparisons). Blood lactate concentration during resting period was significantly lower, while muscle glycogen consumption was greater AR method than PR method (p<0.05 for both). A long resting period between consecutive intense anaerobic exercises may prevent the decline in external power and work. Additionally, AR has more favorable effects on muscle glycogen consumption, resulting in very low muscle glycogen levels, even with a small total amount of exercise.
The purpose of this study was to investigate the influence of physiological factors which effect oxygen kinetics and energy system contribution on the power of Wingate test (WT), with focusing on the difference of aerobic capacity. Twenty three male track and field athletes (sprinters, long distance runners and decathletes) performed the WT on electromagnetic-braked cycle ergometer. The applied resistance was 7.5% of body weight, and the duration was 60 seconds. Moreover, aerobic capacity (maximal oxygen uptake [VO2max]) was determined by an incremental test, and anaerobic capacity (maximal accumulated oxygen deficit [MAOD]) was determined by a supramaximal constant load test. The oxygen uptake during each test was recorded by a breath-by-breath method. The participants were divided into two group which was high VO2max group (High group; n = 11) and low VO2max group (Low group; n = 12). In the results, although the VO2max was significantly higher in the High group, the MAOD was not significantly different between two groups. The oxygen uptake during WT was significantly higher in the High group, and the accumulated oxygen deficit during WT was significantly higher in the Low group. The aerobic contribution was significantly higher in the High group than in the Low group. In contrast, the anaerobic contribution was significantly higher in the Low group than in the High group. These results suggest that by the difference of aerobic capacity, aerobic and anaerobic energy supply contribution was different in WT.
Background: Exercise training induces various adaptations in skeletal muscles. However, the mechanisms remain unclear. Purpose: Therefore, we conducted 2D-DIGE proteomic analysis, which has not yet been used for elucidating adaptations of skeletal muscle after low-intensity exercise training (LIT). Methods: For five days, rats performed LIT, which consisted of two 3-h swimming exercise with45-m rest between the exercise bouts. 2D-DIGE analysis was conducted on epitrochlearis muscles excised eighteen hours after the final training exercise. Results: Proteomic profiling revealed that, out of 681 detected and matched spots, 22 proteins exhibited changed expression by LIT compared with sedentary rats. All proteins were identified by MALDI-TOF/MS. Conclusion: The proteomic 2D-DIGE analysis following LIT identified expressions of skeletal muscle proteins, includingATPsynα, UQCRC1, dihydrolipoamide dehydrogenase, dihydrolipoamide acetyltransferase, that were not previously reported to change their expressions after exercise-training.
Left-ventricular dysfunction is diagnosed when the heart rate performance curve (HRPC) of patients deflects upwards during incremental exercise. The aim of this study was to investigate the effect of exercise training on the upward deflection of the HRPC in patients with cardiovascular disease. This study comprised 11 patients who had cardiovascular disease and showed an upward deflection of the HRPC. The patients underwent exercise training (aerobic training, AT intensity: 30-40 minutes, 2-3 sessions/week, and 3-month follow-up). The HRPC of the patients was measured before and after exercise training. We used a method described by Pokan for evaluating the HRPC; the performance curve (PC) index ([PC1 - PC2] × [1 + PC1 × PC2]-1) was calculated from PC1 and PC2. PC1 and PC2 refer to the heart rate response before and after the O2 pulse deflection point, respectively. The PC index indicates the following: PC > 0.1, downward deflection; -0.1 ≤ PC ≤ 0.1, linear time course; PC < -0.1, upward deflection. The PC index significantly increased after exercise training (from -0.22 ± 0.09 to -0.14 ± 0.07; p < 0.05). In addition, the HRPC of 4 patients (37%) changed in linear time course. These results suggest that an upward deflection of the HRPC in patients with cardiovascular disease may shift to a linear time course after exercise training.
[Objective] Perspiration is almost only heat radiation mechanism under high temperature environments. And sudoriferous water is supplied from blood. Blood flow is determined by blood fluidity, blood volume and the cardiovascular system. It was reported that strong stress decreased blood fluidity. In this experiment, we investigated the relation between blood fluidity and water supply in rats loaded with forced exercise in high temperature environment. [Methods] SPF male Wistar rats weighing 250g were used. All animals were put in high temperature environment (Wet Bulb Globe Temperature; WBGT: 28°C) through whole experimental period. The rats were divided into four groups randomly; Suitable temperature environment-Exercise-Non water intake (SEN), High temperature environment-Exercise-Non water intake (HEN), High temperature environment-Exercise-Water intake (HEW) and Baseline (BL). In a group of water supply, distilled water was served before and later exercise by sonde forcibly. The blood was collected before or later of exercise and blood and erythrocyte suspension fluidity were measured. [Results] In the HEN, hydroperoxides, blood sodium, lactic acid and adrenaline increased while blood and erythrocyte suspension fluidity were decreased significantly compared with the BL. In addition, the hematocrit did not increase even if water equivalent to 4% of body weight lost it. [Conclusion] We speculate that exercise in high temperature environment decreases blood fluidity. However, the water supply in exercise that might not be sufficiently improve blood fluidity.