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ABSTRACT: The purpose of this study was to examine the effect of fatigue resulting from supramaximal dynamic exercise on cerebral cortex activity.
Five healthy male subjects (age 24.6+/-0.4 years, body weight 62.9+/-1.1 kg, height 175.3+/-1.2 cm, and maximal O2 uptake per body mass 48.4+/-1.3 ml/kg/min) participated in this study. All subjects performed at 120% of maximal oxygen uptake (VO2peak) on a cycle ergometer until reaching a state of volitional fatigue. Cerebral oxygenation was measured by near-infrared spectroscopy (NIRS) throughout the supramaximal constant exhaustive exercise.
The mean exercise duration of the subjects was 147.2+/-3.4 s. The peak value of blood lactate concentration within 3-10 min after the exercise test was 14.4+/-0.1 mmol/l. Cerebral oxygenation (8.8+/-1.8 micromol/l) was increased significantly during the first minutes of exercise compared with the pre-exercise value (p<0.05) and cerebral oxygenation decreased with the passage of time during exercise. Cerebral oxygenation at the end of exercise decreased significantly compared with the resting value (-29.9+/-3.4 micromol/l, p<0.05).
These findings suggest that the exhaustive exercise induces the decrease of cerebral function and that the fatigue resulting from dynamic exercise decreases the cerebral cortex activity.
The Journal of sports medicine and physical fitness 06/2004; 44(2):215-9. · 0.85 Impact Factor
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ABSTRACT: The purpose of the present study was to determine whether or not the exercise intensity of water-walking for elderly women could be accurately prescribed by heart rate data obtained during treadmill exercise on land. Six healthy female volunteers, with a mean age of 62.2 +/- 4.2 years, took part in this study. Walking on land was performed on a treadmill. Each subject completed three consecutive 4-minute walks at a progressively increasing velocity (40, 60 and 80 m.min-1), with a 1-minute rest after both the first and second walks. The room temperature and relative humidity were 24.5 +/- 0.2 degrees C and 54.8 +/- 4.0%, respectively. Walking in water was performed in a Flowmill, which is a treadmill positioned at the base of a water flume. Each subject completed three consecutive 4-minute walks at a progressively increasing belt and water-flow velocity (20, 30 and 40 m.min-1), with a 1-minute rest after both the first and second walks. The water depth was at the level of the xiphoid process of each subject. The water temperature was 30.7 +/- 0.1 degrees C. The exercise intensity at the highest workrate was equivalent to 44.2 +/- 10.3% of the heart rate reserve (HRR) during water-walking and 38.4 +/- 4.7% of the HRR during land-walking. There was a highly significant linear relationship between heart rate (HR) and oxygen uptake (VO2) during both water-walking and land-walking. The relationship between HR and VO2 in both exercise modes was similar. Thus, the relationship of HR to VO2 derived from a treadmill-graded walking test on land may be used to prescribe exercise intensity for water-walking in thermoneutral water.
Journal of PHYSIOLOGICAL ANTHROPOLOGY and Applied Human Science 10/2001; 20(5):269-74.
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ABSTRACT: The purpose of the present study was to examine the effect of water temperature on the human body during low-intensity prolonged swimming. Six male college swimmers participated in this study. The experiments consisted of breast stroke swimming for 120 minutes in 23 degrees C, 28 degrees C and 33 degrees C water at a constant speed of 0.4 m.sec-1 in a swimming flume. The same subjects walked on a treadmill at a rate of approximately 50% of maximal oxygen uptake (VO2max) at the same relative intensity as the three swimming trials. Rectal temperature (Tre) in 33 degrees C water was unchanged during swimming for 120 minutes. Tre during treadmill walking increased significantly compared to the three different swimming trials. Tre, mean skin temperature (Tsk) and mean body temperature (Tb) in 23 degrees C and 28 degrees C water decreased significantly more than in both the 33 degrees C water and walking on land. VO2 during swimming in 23 degrees C water increased more than during swimming in the 28 degrees C and 33 degrees C trials; however, there were no significant differences in VO2 between the 23 degrees C swimming trial and treadmill walking. Heart rate (HR) during treadmill walking on land increased significantly compared with HR during the three swimming trials. Plasma adrenaline concentration at the end of the treadmill walking was higher than that at the end of each of the three swimming trials. Noradrenaline concentrations at the end of swimming in the 23 degrees C water and treadmill walking were higher than those during the other two swimming trials. Blood lactate concentration during swimming in 23 degrees C water was higher than that during the other two swimming trials and walking on land. These results suggest that the balance of heat loss and heat production is maintained in the warm water temperature. Therefore, a relatively warm water temperature may be desirable when prolonged swimming or other water exercise is performed at low intensity.
Journal of PHYSIOLOGICAL ANTHROPOLOGY and Applied Human Science 06/2001; 20(3):199-206.
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ABSTRACT: The purpose of the present study was to examine the physiological responses to water-walking using the Flowmill, which has a treadmill at the base of a water-flume, in two groups of women. In the first group, the women were known to regularly swim and exercise in water (group A), while in the second, they did not routinely participate in water-exercise (group B). In both groups, twelve healthy female volunteers in their fifties participated in the study. All of the subjects walked in water using the Flowmill for the first time. Subjects completed four consecutive bouts of 4-minute duration at progressively increasing speeds (20, 30, 40, and 50 m.min-1), with 1-minute rests between each bout. In addition, water-velocity was adjusted to the walking speed of each bout. The water-depth of the Flowmill was the level of the xiphoid process. The water and room temperatures were 30.3 +/- 0.1 degrees C and 24.9 +/- 0.4 degrees C, respectively. In both groups, the relationship between walking speed and oxygen uptake (VO2) as well as that between walking speed and heart rate (HR) changed exponentially as the walking speed increased, and the relationship between HR and VO2 was linear. The relationship between HR and VO2 was similar in both groups, and there was no significant difference between the predicted maximal oxygen uptake (VO2max) of the two groups. VO2 and HR of group B during water-walking, however, were significantly higher than those of group A at all walking speeds. The results of this study clearly showed that experience in moving through the water strongly affects physiological responses to water-exercise, even when fitness levels are equivalent.
Journal of PHYSIOLOGICAL ANTHROPOLOGY and Applied Human Science 04/2001; 20(2):119-23.
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ABSTRACT: The purpose of this study was to examine the physiological responses and RPE during water walking using the Flowmill, which has a treadmill at the base of a water flume, in order to obtain basic data for prescribing water walking for people of middle and advanced age. Twenty healthy female volunteers with an age of 59.1 +/- 5.2 years took part in this study. They belonged to the same swimming club and regularly swam and exercised in water. Walking in water took place in the Flowmill. Subjects completed four consecutive bouts of 4 min duration at progressively increasing speeds (20, 30, 40 and 50 m/min) with 1 min rest between each bout. In addition, water velocity was adjusted to the walking speed of each bout. Subjects were instructed to swing both arms in order to maintain their balance during walking in water. The water depth was to the level of the xiphoid process and the water temperature was 30.31 +/- 0.08 degrees C. Both heart rate (HR) and oxygen uptake (VO2) increased exponentially as walking speed increased. HR was 125 +/- 15 bpm, and VO2 was 18.10 +/- 2.72 ml/kg.min-1 during walking in water at 50 m/min, which was the highest speed. The exercise intensity at this speed was equivalent to 5.2 +/- 0.8 Mets. The relationship between HR and VO2 during walking in water showed a highly significant linear relationship in each subject. There was also a highly significant linear relationship in the mean HR and VO2 of all subjects. Blood lactate concentration (LA) measured at rest and immediately after each bout was 1.1 +/- 0.4 mmol/l at rest, 1.0 +/- 0.2 mmol/l at 20 m/min, 1.0 +/- 0.3 mmol/l at 30 m/min, 1.1 +/- 0.2 mmol/l at 40 m/min, and 2.4 +/- 0.7 mmol/l at 50 m/min. LA at 50 m/min was significantly higher than at rest and at the other speeds. The relationship between HR and RPE during walking in water showed a highly significant linear relationship. The relationship between walking speed and energy expenditure calculated from VO2 and the respiratory exchange ratio (R) showed a high significant exponential relationship. These results suggested that HR and RPE can be effective indices for exercise prescription during Flowmill walking as with land walking.
Journal of PHYSIOLOGICAL ANTHROPOLOGY and Applied Human Science 08/2000; 19(4):195-200.
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S Umemura,
T Kawasaki,
T Ishigami,
T Fujita,
K Hibi,
M Kawasaki,
K Itoh,
Y Yoshimizu, T Ogaki,
G P Acharya,
M Ishii
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ABSTRACT: It has recently been found that there were very few hypertensives in the inhabitants of one Nepalese village, even though their salt consumption, per capita, was as high as citizens in many western countries. To evaluate the genetic factors involved in this phenomenon, we studied whether they had a special genotype distribution of angiotensin-converting enzyme (ACE) gene I/D polymorphism, which was recently reported to be involved in salt sensitivity. One hundred and thirty-eight subjects were evaluated in Nepal. Only nine subjects (6.5%) in this population were hypertensives (over 140/90 mm Hg) while consuming 11 g salt/day, which confirmed the previous results. The distribution of genotypes and alleles of ACE gene I/D polymorphism was similar to that in the Japanese and Chinese, who had five-times more hypertensives while consuming almost as much salt as Nepalese, but significantly different from those in Caucasians. The present study reports, for the first time, the genotype distribution of ACE gene I/D polymorphism in Nepalese subjects. Furthermore, the results suggest ACE gene polymorphism may not be involved in the 'salt-resistance' in this population.
Journal of Human Hypertension 09/1998; 12(8):527-31. · 2.80 Impact Factor
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ABSTRACT: The aim of this study was to examine if the pattern of fluid intake with a carbohydrate-electrolyte solution during 4 h recovery from prolonged, submaximal running would influence the subsequent endurance capacity. Seven well-trained athletes aged 19.8 +/- 0.3 years (mean +/- s(mean)) took part in the study, which had university ethical committee approval. They ran at 70% VO2 max on a level treadmill for 90 min (T1), or until volitional fatigue, whichever came first, on two occasions, at least 7-10 days apart. Four hours later, the subjects ran at the same speed for as long as possible (T2), as a measure of their endurance capacity. During the 4 h rehydration recovery period, the runners were allowed to drink a carbohydrate-electrolyte solution (6.9% Lucozade-Sport; sodium, 24 mmol l(-1); potassium, 2.6 mmol l(-1); calcium, 1.2 mmol l(-1); osmolality, 300 mOsm kg(-1)) ad libitum on one occasion. On the other occasion, the volume of the same fluid was prescribed from calculations of the body mass loss during T1 (2.6% of pre-exercise body mass). All subjects completed the 90 min run during T1 on both trials. However, during T2, in the prescribed intake trial, the exercise time to exhaustion was 16% longer (P< 0.05) than during T2 in the ad libitum trial (69.9 +/- 9.1 vs 60.2 +/- 10.2 min). Although there was no difference between conditions in the total volume ingested (1499 +/- 155 vs 1405 +/- 215 ml), the volume of carbohydrate-electrolyte solution ingested in the fourth hour of the rehydration recovery period was greater in the prescribed intake trial than in the ad libitum trial (258 +/- 52 vs 78 +/- 34 ml; P< 0.05). The amount of glucose ingested in this period during the prescribed intake trial was also greater than during the ad libitum trial (17.8 +/- 3.6 vs 5.4 +/- 2.4 g; P< 0.05). There was a higher blood lactate concentration at the start of T2 in the prescribed intake trial than in the ad libitum trial (1.12 +/- 0.20 vs 0.94 +/- 0.09 mmol l(-1); P< 0.05), but there were no differences in blood glucose, plasma insulin, free fatty acid concentrations or urine volume between trials. The results of this study suggest that drinking a prescribed volume of a carbohydrate-electrolyte solution after prolonged exercise, calculated to replace the body fluid losses, restores endurance capacity to a greater extent than ad libitum rehydration during 4 h of recovery, even though the total volumes ingested were the same between trials.
Journal of Sports Sciences 02/1998; 16(2):143-52. · 1.93 Impact Factor
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M Kawasaki,
T Kawasaki, T Ogaki,
K Itoh,
S Kobayashi,
Y Yoshimizu,
K Aoyagi,
A Iwakawa,
S Takahashi,
S Sharma,
G P Acharya
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ABSTRACT: To determine the seroprevalence of Helicobacter pylori infection in Nepal.
H. pylori infection was identified using a specific and sensitive enzyme-linked immunosorbent assay for anti-H. pylori immunoglobulin G.
Serum samples were collected from 1142 inhabitants (age range 4-93 years) from two villages: Kotyang, a rural isolated village (250 men, 210 women) and Bhadrakali, a suburban village of Kathmandu (334 men, 348 women).
The overall prevalence of H. pylori infection was 56.8%, while significantly higher prevalence was found in the suburban village (Bhadrakali; 67.2%) than in the rural village (Kotyang; 41.5%). This difference was generally reflected by the infection rate in the 10-14-year-old age-group (Bhadrakali, 60% compared with Kotyang, 22.2%). The prevalence of infection significantly increased with age, while no significant difference was found in the prevalence of infection by gender. There was no difference in H. pylori positivity between individuals with and without upper abdominal symptoms in both villages.
There was a significant regional difference in the seroprevalence of H. pylori within Nepal, which showed lower prevalence in an isolated rural village. This difference was mainly caused by the different acquisition rate in teenagers, thus indicating that the teenage lifestyle of this particular environment seemed to be the major determinant in the acquisition of H. pylori infection in the population.
European Journal of Gastroenterology & Hepatology 01/1998; 10(1):47-50. · 1.76 Impact Factor
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ABSTRACT: The aim of this study is to investigate how the blood pressure (BP) circadian rhythm (CR) is influenced by life style. Two groups of subjects were recruited from Nepal and Japan because of the extremely different occupational routines of these countries. The Nepalese represent a rural culture, while the Japanese reflect an industrialized civilization. Both the ethnic groups have in common a high dietary sodium intake. The BP monitoring was estimated according to chronobiological methods. Results provide evidence for a phase difference in BP CR which is coherent with the life style in the two groups. Furthermore, the estimates demonstrate that the Japanese show a higher level in daily BP which is related to the greater number of hours in which they are active. These findings may be taken into account for better deciphering of what is the role of life style on BP physiology in human beings.
Journal of Human Hypertension 06/1996; 10(5):281-5. · 2.80 Impact Factor
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ABSTRACT: The prolonged effects of steady-state exercise and meals on plasma sulpho-conjugated catecholamines (CA) after exercise were examined. Seven male subjects exercised on 2 separate days for 60 min at 50% and 70% of maximal oxygen uptake (VO2max) on a cycle ergometer and then rested, for 8 h sitting in an armchair. A control trial without any exercise was also performed. At 2 h after the end of exercise the subjects were given a meal. The plasma free and sulphated CA, oxygen uptake (VO2) and heart rate (HR) were all measured before exercise, during exercise and hourly during the 8-h recovery period. The sulphated noradrenaline (NA-S) and adrenaline (A-S) concentrations increased after exercise, and, furthermore, only the NA-S concentrations remained elevated for 6 h after exercise at 50% VO2max and for 8 h at 70% VO2max trial, compared with the control trial. There were no changes in either the plasma NA-S or A-S concentrations after consuming a meal, whereas the dopamine sulphate concentration demonstrated a dynamic change. A significantly higher excess postexercise VO2 was observed at 2 h postexercise at 50% VO2max and at 6 h postexercise at 70% VO2max trials. The mean HR was still elevated at 6 and 8 h after exercise, which closely correlated with the duration of the elevated NA-S concentrations. These results suggest that sulphated CA, especially NA-S, could represent an additional index of sympathetic nerve activity after exercise, and that a meal containing small amounts of the amines would seem to have no effect on plasma NA-S and A-S concentrations.
European Journal of Applied Physiology and Occupational Physiology 02/1995; 72(1-2):6-11.
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ABSTRACT: The present study was designed to compare cardiorespiratory responses of swimmers to swimming and running. Six male trained college swimmers performed maximal work test (progressive method) in flume swimming and treadmill running. VEmax during swimming (128.3 +/- 20.6 l/min) was about 4% lower than during running (133.2 +/- 9.9 l/min). VO2max during swimming (3628 +/- 228 ml/min) was significantly higher than during running (3408 +/- 222 ml/min). HRmax during swimming (191 +/- 8 beats/min) was significantly lower than during running (198 +/- 6 beats/min). VO2 at ventilatory threshold (VT) during swimming (2177 +/- 183 ml/min) was significantly higher than during running (1699 +/- 214 ml/min). %VO2max at VT during swimming (60.1 +/- 4.2%) was significantly about 10% higher than during running (49.8 +/- 4.4%). These results suggest that subjects of this study have specific cardiorespiratory adaptation to swimming from a long period of swim training.
The Annals of physiological anthropology = Seiri Jinruigaku Kenkyūkai kaishi 06/1993; 12(3):145-50.
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ABSTRACT: To investigate the nutritional condition in a hilly village (Kotyang) and a suburban village (Bhadrakali) in Nepal and to clarify the possible cause of the difference in total serum cholesterol level between the two groups of villagers habitually eating low fat diets, we carried out a nutrition survey using the 24-h recall method and blood sampling in 403 subjects (204 men and 199 women) in the hilly village and 466 (244 men and 222 women) in the suburban village. Total serum cholesterol was statistically significantly lower in the hilly villagers than in the suburban villagers for both sexes, but HDL-cholesterol was not. In both villages, 82% of the total energy was taken from carbohydrate, 7-8% from fat and 10% from protein. Energy, protein, fiber, potassium, magnesium, monounsaturated fatty acid, polyunsaturated fatty acid, and vitamin A in the hilly villagers were significantly higher than those in the suburban villagers. Total serum cholesterol was significantly associated with age and body fat percentage, suggesting that total serum cholesterol level was not directly associated with total fat intake in these Nepalese people.
Journal of Nutritional Science and Vitaminology 05/1993; 39(2):127-39. · 1.20 Impact Factor
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ABSTRACT: The relation between BP and the factors influencing an increase in BP with age were investigated in the inhabitants of two representative hilly (Kotyang: 206 men and 212 women) and suburban (Bhadrakali: 265 and 244) villages in Nepal. BP for both sexes was statistically significantly higher in Bhadrakali than in Kotyang. Neither hypertension nor elevation of BP with age for men and very few women (1.4%) with hypertension were observed in Kotyang, while 10.9% of men and 4.9% of women were found to be hypertensive in Bhadrakali. Average urinary Na excretion was 183-221 mEq/day in both villages. Urinary Na/K ratio, percentage body fat (%Fat), total protein, total cholesterol and serum Ca were statistically significantly higher in Bhadrakali than in Kotyang, and maximal oxygen uptake and serum Mg were higher in Kotyang. In spite of high salt consumption, there was no increase in BP with age in Kotyang's males, suggesting that the BP may be influenced by physical activity, fat-free mass and nutrient consumption in addition to the high sodium intake, and that extremely high physical activity and very low %Fat could serve to mute the influence of high sodium intake.
Journal of Human Hypertension 05/1993; 7(2):131-40. · 2.80 Impact Factor
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ABSTRACT: A comparative study of % fat was carried out on Nepali children (Ranging from 6 to 18 years old) to clarify the cause of obesity attended with modernization. 126 males and 79 females who have a natural living style, in rural district (KV) and 166 males and 133 who have a living style affected by the rapid urbanization, in suburban district (BV) were selected as subjects. %Fat was estimated from skinfold thickness according to the method of Nagamine (1975). The results summarized as follows. 1) Mean %Fat of BV in each age were clearly higher than those of KV with coincidental age, especially in male subjects. 2) According to the previous reports (Yoshimizu et al., 1990; Ito et al., 1989), it's considered physical activities in the subjects of BV were lower than those of the subjects in KV. But we could not found the nutritional factors to explain the difference of % fat between BV and KV. From these results, it's considered the difference of % fat in both districts is due to the difference of their physical activities.
The Annals of physiological anthropology = Seiri Jinruigaku Kenkyūkai kaishi 05/1991; 10(2):101-7.
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ABSTRACT: Measurements of %Fat, nutrient intake and maximal aerobic power (MAP) were carried out on Nepalese to clarify the cause of obesity attended with modernization. One hundred thirty-two males (KV) who have a natural living style, 20-84 years of age, in rural district and 237 males who have a living style affected by the rapid urbanization, in surburban district were selected as subjects. The subjects of surburban district were divided into two groups. One of them included 147 farmers (BF) who engage in not mechanized farming, 20-73 years of age. Another group included 90 students and wage laborers (BNF) who go to and from Kathmandu (the capital of Nepal), 20-57 years of age. %Fat was estimated from skinfold thickness according to the method of Nagamine (1975). The survey for the nutrient intake was carried out by the 24-hour recall method to obtain the individual food consumption using the food models. Measurement of MAP was made indirectly by the modified of Margaria et al (1965). The main results are summarized as follows. 1) Mean %Fat and the appearance rates of obesity in each age group showed high values in following order: BNF greater than BF greater than KV. 2) Mean caloric intake in KV was higher than those in BF and in BNF an almost all age groups and no significant difference was found between BF and BNF in all age groups. 3) No significant differences in mean fat intake and in mean animal fat intake among all groups were found in almost all age groups.(ABSTRACT TRUNCATED AT 250 WORDS)
The Annals of physiological anthropology = Seiri Jinruigaku Kenkyūkai kaishi 08/1990; 9(3):265-73.
