The purpose of this study was to investigate the gender differences in thermoregulatory responses during the recovery from prolonged exercise. Fourteen (7 males and 7 females) subjects cycled for 45 minutes at 55%VO2max and then rested for 105 minutes in the hot and humid environment (30℃, 80% relative humidity) or cool environment (20℃, 60% relative humidity). Both males and females showed same variations in rectal temperature (Tre) during exercise and recovery periods. Total sweat volume and water intake were significantly larger in males than in females during recovery in the both environments. In the heat condition, mean skin temperature (Tsk) decreased immediately after the cessation of exercise in females but not in males (the recovery period (R) 5–15 min : p<0.01, R15–20 min : p<0.05). These results suggested there are gender-related differences in the mechanisms and also the process maintaining the balance of heat production and heat loss response during recovery from prolonged exercise. Moreover the heat might modify gender differences of heat loss response during recovery as an important factor.
Aerobic exercise is known to reduce pulse wave velocity (PWV), which reflects arterial stiffness. However, aerobic exercise has a depressor effect, and PWV strongly depends on blood pressure (BP). Therefore, improvement of PWV with aerobic exercise may have an indirect effect on reducing BP. In this study, the relationship between changes in BP and regional PWV measured by oscillometric and tonometry sensors before and after exercise therapy emphasizing aerobic exercise was evaluated in 46 elderly people receiving outpatient treatment for lifestyle-related diseases (7 males and 39 females, mean age : 68 years). In all subjects, BP and PWV measurements were performed before and after exercise therapy. PWV was measured between the brachium and ankle (baPWV), between the heart and femoral artery (hfPWV), and between the femoral artery and ankle (faPWV). During 6 months of exercise therapy, BP, baPWV, hfPWV and faPWV decreased significantly. By multiple regression analysis, the changes in systolic BP were extracted as factors correlated with changes in baPWV and faPWV. The changes in baPWV (r=0.639, p<0.01) and faPWV (r=0.649, p<0.01) correlated significantly with changes in systolic BP. However, changes in hfPWV were not extracted as a factor correlated with changes in systolic BP (r=0.228, p=n. s). In conclusion, exercise therapy emphasizing aerobic exercise was suggested to reduce the stiffness of both the lower limb artery (peripheral artery) and the aorta (central artery). Peripheral arterial stiffness improved concurrently with a reduction in BP as a result of exercise therapy ; but there is a possibility that the improvement of central arterial stiffness is not dependent on reducing BP.
PURPOSE : The purpose of this study was to clarify the effects of prolonged expiration (PE) on respiratory and cardiovascular responses and autonomic nervous activity during the exercise.METHODS : Twenty-five healthy men (22±1years) were classified according to the breathing mode during the exercise : 2-second inspiration and 4-second expiration in 1 : 2 group, 3-second inspiration and 3-second expiration in 1 : 1 group and normal breathing in control group. The 6-minute exercise was performed at anaerobic threshold (AT) and 60%AT using a cycle ergometer as an exercise protocol. Respiratory rate (RR) and tidal volume (TV) were measured by the expired gas analysis. The power of low- (LF) and high-frequency components (HF) was analyzed from a Holter electrocardiogram to assess the heart rate variability. RESULTS : RR and LF/HF were significantly lower, TV and HF were significantly higher during the exercise of 60%AT and AT in the 1 : 1 and 1 : 2 groups than in the control group (P<0.05 or P<0.01). The increase of HR was significantly lower and that of HF was significantly higher during the exercise at 60%AT in the 1 : 2 group than in the 1 : 1 group (P<0.05). CONCLUSION : PE activated the parasympathetic nervous activity and consequently restrained an excessive increase of HR during the exercise at 60%AT.
To investigate the influences of high-intensity training and/or a single bout of exercise on in vitro Ca2+-sequestering function of the sarcoplasmic reticulum (SR), the rats were subjected to 8 weeks of an interval running program (final training : 2.5-min running×4 sets per day, 50 m/min at 10% incline). Following training, both trained and untrained rats were run at a 10% incline, 50 m/min for 2.5 min or to exhaustion. SR Ca2+-ATPase activity, SR Ca2+-uptake rate and carbonyl group contents comprised in SR Ca2+-ATPase activity were examined in the superficial portions of the gastrocnemius and vastus lateralis muscles. For rested muscles, a 12.7% elevation in the SR Ca2+-uptake rate was induced by training. Training led to improved running performance (avg time to exhaustion : untrained-191.1 vs trained-270.9 sec ; P<0.01). Regardless of training status, a single bout of exercise caused progressive reductions in SR Ca2+-ATPase activity and SR Ca2+-uptake rate. Increases in carbonyl content only occurred after exhaustive exercise (P<0.05). At both point of 2.5-min and exhaustion, no differences existed in SR Ca2+-sequestering capacity and carbonyl content between untrained and trained muscles. These findings confirm the previous findings that oxidative modifications may account, at least partly, for exercise-induced deterioration in SR Ca2+-sequestering function ; and raise the possibility that in the final phase of acute exercise, high-intensity training could delay the progression of protein oxidation of SR Ca2+-ATPase.
The purpose of this study was to investigate the changes in maximal oxygen consumption, muscle mass, whole bone mineral density, and risk factors for falls after 24 weeks of multi-component exercise training. Subjects were consisted of forty elderly women from the same community who had an MMSE score higher than 24. The combined exercise program included stretching for 20 minutes, low impact aerobic exercise for 30 minutes, and 30 minutes of resistance training. The program was conducted 3 times a week for 24 weeks. We found that the VO2max, muscle mass, and BMD of greater trochanter were significantly increased. Balance function and body sway were also significantly improved. Therefore, it appears that increased physical activity through multi-component exercise training plays a positive role in improving body composition and reducing risk factors for falls due to aging.
The purpose of this study was to investigate the acute effects on excess post-exercise oxygen consumption (EPOC) of low intensity and slow-movement repetitive resistance exercise in moderately trained young men. Seven healthy trained young men (age=22±3 yr ; height=172.5±4.0 cm ; weight=69.5±8.3 kg ; VO2max=47.3±6.0 ml/kg/min) performed the following three exercise patterns on separate days : 1) high-intensity (80% one-repetition maximum : 1RM) and regular-movement repetitive exercise (1 second each of concentric and eccentric action, termed high and regular exercise (HRE) ; 2) low-intensity (50%1RM), regular-movement repetitive exercise (same movement speed as for HRE but termed low and regular exercise (LRE); and 3) low-intensity (50%1RM), slow-movement repetitive exercise (4 sec each of concentric and eccentric action, termed low and slow exercise (LSE). These three exercise patterns consisted of three sets of four exercises performed to maximum repetition. All subjects completed the three exercise sessions in a randomized and counterbalanced fashion. Oxygen consumption (VO2) and heart rate (HR) were continuously monitored during the exercise sessions and for 90 min afterwards. EPOC over 90 min was thus observed after completing the three exercise patterns. However, there were no significant differences in EPOC among the three exercise patterns. The results of this study suggest that low-intensity and slow-movement repetitive resistance exercise with maintaining muscular tension (LSE) is likely to increase EPOC to the same extent as HRE and LRE exercise patterns.
We evaluated the influence of a twice-weekly group exercise program on visceral fat area (VFA) and plasma adiponectin (APN) in the elderly. Thirty-three community-dwelling elderly (age : 72.4±6.9 yrs) participated in a 12-week supervised, geriatric exercise training program (GET) followed by a 12-week unsupervised GET (u-GET), which included stretching, strengthening, and balance-training exercises. Participants were evaluated for physical fitness, blood glucose, HbA1c, triglyceride, cholesterol, insulin, and APN. VFA was measured by computed tomography. All measurements were taken before the GET (TR1), after 12-weeks of GET (TR2), and at the end of the u-GET (TR3). Twelve weeks of GET produced significant increases in physical function measures. Both walking speed and functional mobility values at TR3 were significantly higher than TR1 values. A significant reduction in VFA was seen at TR3 in men. APN progressively elevated from TR1 to TR3 in women. In the frail elderly, 12 weeks of GET effectively increased functional ability and APN. The beneficial effects on VFA and APN were sustained following the participation in the unsupervised setting, suggesting that the frail elderly should be encouraged to participate and maintain a resistance training routine to achieve preferable effects on both functional ability and cardiovascular risk factors.
It is well known that patients with lower extremity arthritis have difficulty in postural control. Previous studies have shown the long-term effects of aquatic exercise on postural control ; in this study, we investigated the acute effects. The center of pressure (COP) was measured in 7 females with lower extremity arthritis (age, 60.4±7.1 years) in the upright position before and after a 60-min aquatic exercise session. It was also measured before and after a 60-min rest (sitting) session conducted on a different occasion. The COP was recorded for 30 s with eyes open. The time and frequency domain measurements of the COP were analyzed, and the pre- and post-session results were statistically compared using a paired t test. In the aquatic exercise session, there were significant differences (p<0.05) between the pre- and post-session values in the frequency domain measurements of velocity power spectrum : the distribution of power shifted to a lower frequency area ; however, there were no significant differences in the time domain measurements. This change in the frequency domain measurements suggests the possibility of acute effects of aquatic exercise on postural control in patients with lower extremity arthritis.
After a single bout of prolonged strenuous exercise, inflammatory and muscle damage markers increase. The present study investigated whether vitamin E supplementation can attenuate inflammatory (C-reactive protein (CRP) and interleukin-6 (IL-6)) and muscle damage (creatine kinase (CK) and lactate dehydrogenese (LDH)) markers after prolonged repeated bouts of cycling in healthy young men. Eight young males (aged 21–30 y) were received both vitamin E supplement (300 mg/day) and placebo (control) for 14 days separated by at least an interval of 1 month in a randomised, counterbalanced design. On day 12 of both trials, subjects cycled at 80% of maximal heart rate in two, 90-min bouts (150 min rest between each). Blood samples were collected on days 1 (baseline), 12 (pre- and post-exercise 1 and pre- and post-exercise 2), 13, 14, and 15. After 14 days of supplementation, serum α-tocopherol concentrations increased in the vitamin E trial (P<0.0005) but not the placebo trial. Serum CRP concentrations did not differ between trials and did not significantly change over the observation period in both trials. Serum IL-6, CK, and LDH concentrations increased (P≤0.024) in response to repeated bouts of exercise in both trials but did not differ between trials. The study demonstrates that short-term vitamin E supplementation appears to have no effect on attenuating markers of inflammatory and muscle damage in response to repeated bouts of prolonged exercise in healthy young men.