Resistance exercise enhances cognitive function in mouse.

Physical exercise has been shown to increase adult neurogenesis in the hippocampus and to enhance synaptic plasticity. It has been demonstrated that these neuroprotective effects can be observed following aerobic exercise. However, it remains unknown whether plasticity molecules, such as brain-derived neurotrophic factor (BDNF) and cyclic AMP response element-binding protein (CREB), are expressed in the hippocampus following resistance exercise. We applied voluntary progressive-resistance wheel exercise (RE) for 14 days, and measured BDNF and CREB in the hippocampus. The Morris water maze was also performed to estimate learning and memory. Furthermore, we measured RE effects on mammalian target of rapamycin (mTOR) and 70-kDa ribosomal protein S6 kinase (p70S6K) mediating muscle protein synthesis in the soleus. As a result, we found that RE enhanced cognition and elevated BDNF and CREB expressions in the hippocampus. Also, RE activated the mTOR-p70S6K signaling pathway in the soleus. We found that phosphorylated mTOR and p70S6K were significantly positively correlated with BDNF expression. Our results indicated that resistance exercise drove the protein synthesis signaling pathway in the soleus and enhanced hippocampal synaptic plasticity-related molecules. These results suggest the beneficial effects of resistance exercise on cognitive function.

Relationship between reduced lower abdominal blood flows and heart rate in recovery following cycling exercise.

AIM: To examine the blood flow (BF) response in the lower abdomen (LAB) in recovery following upright cycling exercise at three levels of relative maximum pulmonary oxygen consumption (VO(2max)) and the relationship of BF(LAB) to heart rate (HR) and target intensity. METHODS: For 11 healthy subjects, BF (Doppler ultrasound) in the upper abdominal aorta (Ao) above the coeliac trunk and in the right femoral artery (RFA) was measured repeatedly for 720 s after the end of cycling exercises at target intensities of 30%, 50% and 85% VO(2max), respectively. Blood flow in the lower abdomen (BF(LAB)) can be measured by subtracting bilateral BF(FAs) (≈twofolds of BF(RFA)) from BF(Ao). Change in BF(LAB) (or BF(LAB) volume) at any point was evaluated by difference between change in BF(Ao) and in BF(FAs). Heart rate and blood pressure were also measured. RESULTS: At 85% VO(2max), significant reduction in BF(LAB) by approx. 89% was shown at 90 s and remained until 360 s. At 50% VO(2max), reduction in BF(LAB) by approx. 33% was found at 90 s although it returned to pre-exercise value at 120 s. On the contrary at 30% VO(2max), BF(LAB) showed a light increase (<20%) below 70 bpm of HR. There was a close negative relationship (P < 0.05) between change in BF(LAB) and recovery HR, as well as between change in BF(LAB) volume and both recovery HR and % VO(2max). CONCLUSION: This study suggests that the lower abdominal BF in recovery may be influenced by sympathetic-vagus control, and dynamics of BF(LAB) may be closely related to the level of relative exercise intensities.

Relation of the stages of change for exercise behaviors, self-efficacy, decisional-balance, and diet-related psycho-behavioral factors in young Japanese women.

BACKGROUND: A large proportion of young Japanese women is inactive. Exercise has important health benefits, however, abnormal weight/eating concerns and excessive dieting practices among physically active young women also have been reported in many cross-sectional studies. The purpose of this study was to examine the relationships between stages of change for exercise behaviors and exercise/dieting related psycho-behavioral factors using the Transtheoretical Model of behavior change as a theoretical framework. METHODS: A cross-sectional study included 450 young Japanese women aged 18 to 21 (18.4+/-0.67 years). Subjects in precontemplation (n=111, 24.7%), contemplation (n=120, 26.7%), preparation (n=177, 39.3%), action (n=17, 3.8%), and maintenance (n=25, 5.6%) were compared on physique, body composition, current exercise practices, exercise self-efficacy, decisional balance (benefits and costs exercise), as well as dieting behaviors and weight/eating concerns. RESULTS: Stages of change for exercise behaviors were significantly related to exercise self-efficacy and perceived benefits as well as to dieting behaviors and weight/eating concerns. Subjects in the higher stages had higher self-efficacy, perceived benefits of exercise, and healthy dieting behaviors; however, some of them also had unhealthier dietary practices, higher phobia of obesity and obsession with eating than those in lower stages. CONCLUSIONS: These findings provide support for applying the transtheoretical model of exercise behavioral change to Japanese young women. Additionally, it is also important to pay attention to stage specific psycho-behavioral factors related to their dieting.

Quantitative effects of respiration on venous return during single knee extension-flexion.

Respiration and the muscle pump play major roles in increasing venous return. However, the relative contribution of each of these factors remains unclear. The present study investigates the quantitative effects of interaction between respiration and the muscle pump on femoral venous blood flow (FVBF) during a single voluntary knee extension-flexion (KEF) using duplex-Doppler ultrasound. During various respiration modes, which consisted of arrested respiration, normal respiration and deep respiration (inspiration or expiration), eight subjects performed a supine one-legged voluntary KEF. FVBF was measured during respiration only (Protocol A) and during KEF synchronized with respiration (Protocol B). The difference between FVBF values obtained in Protocol B and Protocol A was defined as DeltaFVBF. When KEF was synchronized with normal or deep respiration, FVBF with inspiration was significantly lower than that with expiration. However, DeltaFVBF was significantly higher with inspiration than with expiration during deep respiration but was not significant during normal respiration. Furthermore, DeltaFVBF was significantly higher at both normal and deep respiration than at arrested respiration. The effects upon the venous return during KEF differed between inspiration and expiration. The present findings indicate that during a single supine KEF, respiration might promote venous return to a range of 1.5- to 2.3-fold DeltaFVBF during arrested respiration.

Effects of shift work on 24-hour ambulatory blood pressure and its variability among Japanese workers.

OBJECTIVES: This study examined the effects of rotating shift work on blood pressure in a comparison of ambulatory blood pressure and long-term changes in blood pressure between shift and day workers. METHODS: Ambulatory blood pressure was measured for 24-hour periods at an interval of 30 minutes for 27 shift workers and 26 day workers when they worked during the day. Blood pressure was compared between these 2 groups of workers for 4 time categories (awake, sleep, nonwork awake, and work periods). Their long-term blood pressures, recorded in annual surveys, were reviewed for long-term changes. These comparisons were adjusted for the effects of body mass index, alcohol intake, anger expression, and physical activity. RESULTS: On the average, sleep time was shorter and the anger-in (ie, anger suppressed) score was higher for the shift workers than for the day workers, but body mass index and alcohol intake did not differ between the 2 groups. Even after adjustment for these co-variables, the mean systolic blood pressure during the 24-hour, awake, and work periods were higher among the shift workers than among the day workers. The 24-hour standard deviations of the systolic blood pressures were also higher for the shift workers than for the day workers. Among the shift workers, but not among the day workers, a significant long-term increase was observed in systolic blood pressure measured in the annual surveys. CONCLUSIONS: These results suggest that shift work may increase systolic blood pressure levels among Japanese men.

Effects of epinephrine and lactate on the increase in oxygen consumption of nonexercising skeletal muscle after aerobic exercise.

The purpose of this study was to measure O2 consumption of nonexercising skeletal muscles (VO2nonex) at rest and after aerobic exercise and to investigate the stimulant factors of O2 consumption. In experiment 1, we measured the resting metabolic rate of the finger flexor muscles in seven healthy males by 31P-magnetic resonance spectroscopy during a 15 min arterial occlusion. In experiment 2, the VO2nonex of the finger flexor muscles was measured using near infrared continuous wave spectroscopy at rest, immediate postexercise, and 3, 5, 10, 15, and 20 min following a cycling exercise at a workload corresponding to 50% of peak pulmonary O2 uptake for 20 min. We also monitored deep tissue temperature in the VO2nonex measurement area and determined catecholamines and lactate concentrations in the blood at rest and immediate postexercise. VO2nonex at rest was 1.1 +/- 0.1 microM O2/S (mean +/- standard error) and VO2nonex after exercise increased 59.6 +/- 7.2% (p < 0.001) from the resting values. There were significant correlations between the increase in VO2nonex and the increase in epinephrine concentration (p < 0.01), and between the increase in VO2nonex and the increase in lactate concentration (p < 0.05). These results suggest that epinephrine and lactate concentrations are important VO2nonex stimulant factors.

Quantification of ischemic muscle deoxygenation by near infrared time-resolved spectroscopy.

The purpose of this study was to quantify muscle deoxygenation in human skeletal muscles using near infrared time-resolved spectroscopy (NIRTRS) and compare NIRTRS indicators and blood saturation. The forearm muscles of five healthy males (aged 27-32 yrs.) were monitored for changes in hemoglobin saturation (SO2) during 12 min of arterial occlusion and recovery. SO2 was determined by measuring the temporal profile of photon diffusion at 780 and 830 nm using NIRTRS, and was defined as SO2-TRS. Venous blood samples were also obtained for measurements of SvO2, and PvO2. Interstitial PO2(PintO2) was monitored by placing an O2 electrode directly into the muscle tissue. Upon the initiation of occlusion, all parameters fell progressively until reaching a plateau in the latter half of occlusion. It was observed at the end of occlusion that SO2-TRS (24.1 +/- 5.6%) agreed with SvO2 (26.2 +/- 6.4) and that PintO2 (14.7 +/- 1.0 Torr) agreed with PvO2 (17.3 +/- 2.2 Torr). The resting O2 store (oxygenated hemoglobin) and O2 consumption rate were 290 microM and 0.82 microM s-1, respectively, values which reasonably agree with the reported results. These results indicate that there was no O2 gradient between vessels and interstisium at the end of occlusion.

Vitamin E level changes in serum and red blood cells due to acute exhaustive exercise in collegiate women.

The purpose of this study was to investigate the change in vitamin E level in both serum and red blood cells (RBC) during exercise and to clarify the effect of vitamin E supplementation. Ten young sedentary female subjects received 200 mg D-alpha-tocopherol acetate daily for 1 wk after the initial exercise bout. After 1 wk of vitamin E supplementation, the same subjects repeated the same exercise. Before vitamin E supplementation, the alpha-tocopherol level in the serum (serum-alpha-tocopherol) did not change after exercise, but a significant decrease in the alpha-tocopherol level in RBC (RBC-alpha-tocopherol) was observed after exercise (p < 0.05). On the other hand, after vitamin E supplementation, the serum-alpha-tocopherol level decreased significantly after exercise (p < 0.05), while the RBC-alpha-tocopherol level was maintained after exercise. Furthermore, a negative correlation between the changes in serum- and RBC-alpha-tocopherol levels was observed only after vitamin E supplementation (r = 0.667, p < 0.05). The present results suggest that as RBC suffers oxidative stress, vitamin E in RBC is consumed to protect RBC from oxidative damage during exercise. These results also suggest that when there is a sufficient amount of vitamin E in the serum, vitamin E is shifted from the serum to RBC, resulting in a steady RBC-alpha-tocopherol level and a decrease in the serum-alpha-tocopherol level under oxidative stress such as exercise.

Vitamin E supplementation and endurance exercise: are there benefits?

It has been widely noted that vitamin E shows numerous beneficial effects through and beyond its antioxidative properties; consequently, vitamin E is expected to prevent degenerative diseases. In the field of sports medicine, many studies dealing with vitamin E have been conducted originally from the point of view of its effects on physical performance. Although some earlier studies indicated that vitamin E supplementation could improve physical performance, defects in the study design or statistical analysis were pointed out at a later time. The majority of subsequent well controlled studies have reported no significant effect on physical performance from vitamin E supplementation. Recent studies suggest that endurance exercise may promote free radical generation in the body, and vitamin E may play an important role in preventing the free radical damage associated with endurance exercise. Although there is evidence of free radical involvement in exercise-induced muscle injury, vitamin E supplementation might not be expected to prevent muscle damage caused by exercise in humans without a vitamin E deficiency. Since it is still unclear whether exercise induces lipid peroxidation in the human body, the beneficial effect of vitamin E supplementation on exercise-induced lipid peroxidation has not yet been established. However, it is proposed that as a result of exercise vitamin E may be mobilised from store tissues and redistributed in the body to prevent oxidative damage. Therefore, we are convinced that vitamin E contributes to preventing exercise-induced lipid peroxidation. It has also been indicated that strenuous endurance exercise may enhance the production of oxidised low density lipoprotein (LDL), which plays a key role in the initiation and progression of atherosclerosis. It is also suggested that this enhanced production of oxidised LDL could be reduced if a higher vitamin E status is maintained. Supplementation with 100 to 200mg of vitamin E daily can be recommended for all endurance athletes to prevent exercise-induced oxidative damage and to reap the full health benefits of exercise.

The relationship between physical fitness and coronary risk factor profiles in Japanese women.

The purpose of this study was to investigate the relationship between physical fitness and coronary risk factor profiles in Japanese women. The subjects were 1,483 women (ages 30 to 69) who participated in a practical health promotion program. After medical examination, physical fitness was evaluated by conducting a symptom limited maximal exercise test by ergometer to measure maximum oxygen uptake (peakVO(2)) with an expired gas analyzer. The subjects were classified into 3 groups (high fitness, moderate fitness, and low fitness) according to age and physical fitness level. The results showed that the subjects in higher fitness groups had lower levels in: body mass index (BMI), percentage of body fat, waist-hip ratio, resting blood pressure, and atherogenic index, and higher HDL-cholesterol compared to those in lower fitness group. Even after adjustment for the effects of age and BMI, die subjects in the higher fitness groups had better coronary risk factor profiles. These results suggest that among Japanese women a high level of physical fitness is related to favorable coronary risk factor profiles.

Reduced blood flow in abdominal viscera measured by Doppler ultrasound during one-legged knee extension.

The redistribution of blood flow (BF) in the abdominal viscera during right-legged knee extension-flexion exercise at very low intensity [peak heart rate (HR), 76 beats/min] was examined by using Doppler ultrasound. While sitting, subjects performed a right-legged knee extension-flexion exercise every 6 s for 20 min. BF was measured in the upper abdominal aorta (Ao), right common femoral artery (RCFA), and left common femoral artery (LCFA). Visceral BF (BFVis) was determined by the equation [BFAo - (BFRCFA + BFLCFA)]. A comparison with the change in BF (DeltaBF) preexercise showed a greater increase in DeltaBFRCFA than in DeltaBFAo during exercise. This resulted in a reduction of BFVis to 56% of its preexercise value or a decrease in flow by 1,147 +/- 293 (+/-SE) ml/min at the peak workload. Oxygen consumption correlated positively with DeltaBFAo, DeltaBFRCFA, and DeltaBFLCFA but inversely with DeltaBFVis during exercise and recovery. Furthermore, BFVis (% of preexercise value) correlated inversely with both an increase in HR (r = -0.89), and percent peak oxygen consumption (r = -0.99). This study demonstrated that, even during very-low-intensity exercise (HR <90 beats/min), there was a significant shift in BF from the viscera to the exercising muscles.

Differences in HDL cholesterol concentrations in Japanese, American, and Australian children.

BACKGROUND: Mortality from coronary heart disease is relatively low in Japan compared with other developed countries and has remained low despite an increasing standard of living and an apparent increase in mean plasma cholesterol concentration in adults over the past three decades. Important differences in childhood plasma lipoprotein profile might contribute to some of the difference in coronary heart disease mortality seen between Japan and both Australia and North America. METHODS AND RESULTS: Plasma HDL cholesterol and total cholesterol were surveyed in representative populations of schoolchildren in Australia, Japan, and Bogalusa, La. The mean concentration of plasma HDL cholesterol (but not total cholesterol) was higher for Japanese schoolchildren than for Australian or US schoolchildren (P<.001). In addition, the difference in plasma HDL cholesterol between the ages of 8 to 10 years and 12 to 15 years was much greater for Australian (boys, 15.2%; girls, 2.6%) and US (boys, 9.1%; girls, 2.7%) children than for their Japanese counterparts (boys, 4.2%; girls, 1.9%). An examination of potential explanatory factors revealed little difference in body mass index between samples, higher physical activity levels for the Japanese compared with the Australians, and substantial differences in dietary intake between Japanese and Australian schoolchildren. CONCLUSIONS: The relatively high ratio of plasma HDL cholesterol to total cholesterol in Japanese schoolchildren and the relatively small negative difference of plasma HDL cholesterol with age may help to explain why the coronary heart disease mortality rate in Japan is low compared with that in other developed countries.

Noninvasive measures of oxidative metabolism on working human muscles by near-infrared spectroscopy.

The purpose of this study was to determine whether the initial rate of hemoglobin and myoglobin deoxygenation during immediate postexercise ischemia, a reflection of muscle O2 consumption (VO2mus), can be a quantitative measure of muscle oxidative metabolism. The finger flexor muscles of five healthy men (aged 25-31 yr) were monitored by 31P-magnetic resonance spectroscopy for changes in phosphocreatine (PCr), Pi, and pH. Tests were conducted during 15 min of cuff ischemia and during 5 min of submaximal isotonic grip exercise at 10, 20, 30, and 40% of maximal voluntary contraction, one contraction every 4 s. The VO2mus changes were also monitored by near-infrared spectroscopy with continuous wave. The VO2mus during exercise was expressed relative to the resting value. The resting metabolic rate, calculated from the PCr breakdown rate after complete O2 depletion, was 0.0010 (SD) mM ATP/s. During submaximal exercise (pH > 6.9), the VO2mus increased with a rise in intensity (0.036 +/- 0.011, 0.054 +/- 0.016, 0.062 +/- 0.012, and 0.067 +/- 0.020 mM ATP/s during 10, 20, 30, and 40% maximal voluntary contraction, respectively) and showed significant correlation with changes in both calculated ADP and PCr values (r2 = 0.98 and r2 = 0.99, respectively). In conclusion, because of the significant correlation with regulatory metabolites (ADP and PCr) of oxidative phosphorylation, O2 decline rate in immediate postexercise ischemia determined by near-infrared spectroscopy with continuous wave can be utilized for the quantitative evaluation of localized muscle oxidative metabolism.

Relationships between exhaustive mood state and changes in stress hormones following an ultraendurance race.

To investigate how the pituitary-adrenal and sympathetic nervous hormones change in psychologically exhaustive states following an ultraendurance race, the Profile of Mood States (POMS), plasma ACTH, beta-endorphin, adrenaline, noradrenaline, and serum cortisol were measured in 29 male athletes two days before, immediately after, and one day after a triathlon. Psychological exhaustion was defined as possessing low POMS vigour and high fatigue immediately post-race. Eleven subjects met the criteria for the exhaustive group, and another ten were placed in the vigour group, which possessed high vigour regardless of fatigue score and the remaining eight subjects were excluded from analysis because they did not satisfy experimental protocol. Student's t-tests revealed no significant group differences in age, race time, pre-race POMS and hormone values. Immediately post-race, serum cortisol and plasma adrenaline did not differ between groups. However, significantly lower levels of plasma beta-endorphin (p = 0.03) and noradrenaline (p = 0.05), and relatively lower levels of plasma ACTH (P = 0.08) immediately post-race were observed in the exhaustive group when compared with the vigour group. We conclude that pituitary and sympathetic nervous hormone reactivity is attenuated following ultraendurance race in athletes showing psychological exhaustion and this is independent of race performance.

Intraindividual relationships between blood pressure level and emotional state.

BACKGROUND: Because of the increasing attention to the association between emotion and blood pressure (BP) during activity, there is a need to examine the subjects' own description of feelings in relation to different levels of BP during activity. METHODS: Fifty-eight Swedish subjects in six occupational groups were instructed to measure their own BP and subsequently record emotions at 1-hour intervals during waking hours. This was repeated during 4 different working days. Emotional states were recorded on a 4-point scale. Relationships between BP and each emotion were analyzed individually. RESULTS: One fourth of the subjects were unable to relate BP variations to emotional states whereas more than one tenth reported correlations between at least five different adjectives and BP. The number of adjectives correlated with systolic BP in an individual was linearly related to the individual's variation in systolic BP-the more significant the adjective the more systolic BP variation. Systolic BP increase with increasing job strain showed a curvilinear relationship with number of adjectives related to systolic BP-those with no significant adjectives and those with excessively many were those who showed the most increase in systolic BP with increasing job strain. CONCLUSIONS: Despite the fact that subjects recorded their emotions after the BP measurement, as many as 25% were unable to see any relationship between emotion and BP. This groups as well as those who described many emotion correlates had marked elevations in systolic BP with increasing job strain.