ABSTRACT
The existing adoptive criterion for VO<SUB>2</SUB>max was created for physically fit subjects who were soldiers and/or sportsmen. However, VO<SUB>2</SUB>max is widely used at present as one of the health-related physical fitness determinants from children to aged persons. It might be appropriate to determine the criterion and the critical values for VO<SUB>2</SUB>max in consideration of age and gender.<BR>The present study attempted to determine the reference range and critical values of the criterion for VO<SUB>2</SUB>max using the iterative truncation method. Voluntary VO<SUB>2</SUB>max was measured in 548 healthy volunteers, aged 8 to 82 years, using a treadmill. The % VO<SUB>2</SUB>max was calculated using the equation of %VO<SUB>2</SUB>max=measured VO<SUB>2</SUB>max × 100 gage-estimated VO<SUB>2</SUB>max. Crude data of %VO<SUB>2</SUB>max was applied to the iterative truncation method, and the reference range of %VO<SUB>2</SUB>max (70-130%VO<SUB>2</SUB>max) was determined. Physiological and biochemical parameters, within the values of 70-130%VO<SUB>2</SUB>max, were converted to a percentage using a similar equation of %VO<SUB>2</SUB>max. The value corresponding to 10% of the lower area of the distribution of each parameter was defined as the critical value, which was the minimum level to adopt as the VO<SUB>2</SUB>max. Taking a single or combined application of the critical value of each parameter, the adoptive ratio of VO<SUB>2</SUB>max was investigated.<BR>The present study indicated that there was no difference between VO<SUB>2</SUB>max selected by the iterative truncation method and that obtained by the existing criterion for VO<SUB>2</SUB>max. The combination of the critical value of HRmax and bLAmax was recommended as a criterion of VO<SUB>2</SUB>max. The reference value, critical value of VO<SUB>2</SUB>max and the critical real value of each parameter were shown as a mean of every 5-year interval with the distinction of gender.
ABSTRACT
The effects of exercise and dietary therapy on the prevention of diabetic nephropathy (DN) were compared. Thirty-two male OLETF rats were divided into four groups (Ex, Diet, Sed, Pre) . Fourteen LETO rats served as the normal controls. Therapy was conducted for 10 weeks from age 22 to 31 weeks. The Ex group was trained by voluntary exercise, and the Diet group had a restricted food intake resulting in the same BW as that of the Ex group. The Ex developed a significant increase in urinary albumin excretion compared to the Diet group, although significantly less than the Sed group. Blood pressure in the Ex group showed a tendency to be higher during therapy. BW and serum lipids were significantly reduced, and glucose intolerance was improved in both the Ex and Diet groups. There were no differences in the metabolic indices between the Ex and Diet groups. The Ex group showed a significantly heavier kidney weight and a tendency for enlargement of the glomerular area and volume. The protective effect of DN through improvement of the metabolic dis-order by exercise might be offset by exercise-induced renal loads. Control of exercise intensity and blood pressure appear to be important as well as the improvement of glucose intolerance and lipid metabolisms in exercise therapy to prevent an occurrence and development of DN.
ABSTRACT
The effect of ingestion of a chilled carbohydrate and electrolyte solution on metabolic and hormonal responses and water-electrolyte balance was studied after two 5-km runs in hot outdoor conditions (Temp, 30.6-30.9°C ; humidity, 61.3-62.4%) . Eight healthy females (mean age 21.8 years) participated in : 1) a control experiment (Copt) with no fluid intake, 2) an experiment with 500 ml of tap water (WI), and 3) an experiment with 500 ml of sports beverage (SB) containing carbohydrate and electrolytes each of which were given after the 1st 5-km run, followed by a second 5-km run with an equivalent to 68.7-72.3% of VO<SUB>2</SUB>max. In the Cont, decreases in %ΔPV and blood glucose (BS) and increases in serum osmolality (Sosm), free fatty acid (sFFA) and plasma hormone concentrations related to regulation of the water-electrolyte balance in the body persisted after the 2 nd run. The intake of the sports beverage prevented hypoglycemia and ketoacidosis, as shown by an increase in sFFA and positive results for qualitative analysis of ketone body in the urine, and quick recovery of plasma volume following an endurance run under a hot environment. This study suggests that fluid replacement with a sports beverage containing carbohydrate and electrolytes was superior to plain water or no fluid ingestion in terms of metabolic and hormonal responses and the recovery of plasma volume and elevated rectal temperature following an endurance run under hot conditions.
ABSTRACT
We examined the relationship between serum magnesium (sMg) change and urinary Mg (uMg) excretion, lipid metabolism and hormonal responses induced by prolonged physical exercise. Six recreational runners voluntary participated in the study, and their sMg, uMg, serum lipid and circulatory levels of plasma hormones (ACTH, cortisol, ADH, aldosterone) were determined during a 1-week recovery period after a full-marathon race. Immediately after the race, fall of sMg was significant, but recovered to the pre-race level in the next day. Urinary Mg excretion decreased significantly after the race and the tubular reabsorption rate (%TRMg) was elevated for one week. The negative correlation between sMg and %TRMg suggested that a decreased level of sMg enhanced tubular reabsorption of Mg. On the other hand, no correlation was observed between the plasma hormone levels and %TRMg, thus hormonal responses induced by prolonged exercise had less effect on the tubular reabsorption of Mg. Therefore, fall of sMg after the full marathon race may not be a reflection of Mg depletion, but seems to be the result of a Mg shift to other regions (muscle, erythrocytes and adipose cells) from the serum. Increased level of serum FFA after the race suggested enhanced lipolysis, which might be a cause of sMg reduction.
ABSTRACT
A cross-sectional study was carried out to investigate the effect of physical exercise in daily lives of healthy women on the aging process in terms of maximal aerobic capacity (VO<SUB>2</SUB>max), body fat tissue mass (FTM), lean tissue mass (LTM), bone mineral density (BMD), serum triglyceride (TG), total cholesterol (TC), HDL-C and LDL-C concentrations, and systolic (SBP) and diastolic blood pressure (DBP) . These parameters are considered as risk factors of cerebrovascular disease and/or osteoporosis, which are the main causes of becoming bedridden and demented in middle-aged and older women. One hundred sixty-five healthy female volunteers aged 20 to 76 years participated in the study, 82 of whom were postmenopausal with a mean age at menopause of 49.7±3.1 years. Eighty-two of the subjects had been exercising regularly by jogging, swimming, aerobic dancing, or playing tennis more than twice a week for 2 years (Ex group), whereas 83 individuals had not been engaging in regular exercise (Cont group) . Serum lipid concentrations, SBP and DBP measurements at rest and treadmill VO<SUB>2</SUB>max and HRmax measurements were determined in the morning after an overnight fast. Whole-body BMD (TBMD), head, lumbar, arm and leg BMD, FTM and LTM were measured by dual-energy X-ray absorptiometry one to two hours after a light lunch. The mean and SD of each measurement were calculated for five-year age groups between 40 and 60 years and one group each under 40 and over 60 years.<BR>The results were as follows:<BR>1, VO<SUB>2</SUB>max (r=-0.590) and HRmax (r=-0.632) decreased significantly with age. The VO<SUB>2</SUB>max of the Ex group was significantly higher than that of the Cont group in all each age groups. However, no differences in the aging process in terms of HRmax were found between the two groups.<BR>2, Resting SBP (r=-0.391) and DBP (r=0.315) increased significantly with age. However, no hypertensive individuals (160/95 mmHg-) were found among the 165 subjects.<BR>3. Only serum TC (r=0.346) and LDL-C (r=0.339) among the blood constituents measured changed with age. No changes in serum HDL-C were detected with age. Lower TC (189.2±23.3 mg/dl) and higher HDL-C (72.2±10.9 mg/dl) were observed in eleven runners (49.7±7.7 years) among the subjects who participated frequently in official races than in subjects of the same ages in the Cont group. The highest serum HDL-C (75.8±15.8 mg/dl) and HDLC/TC ratios (0.362) were noticed among the subjects (n=26) who both regularly exercised and consumed alcoholic beverages.<BR>4. A tendency for FTM to increase and LTM to decrease with age were observed in both groups, and a lower %FTM (percentage of FTM to body weight) and higher %LTM were evident in the Ex group. Differences in %FTM and %LTM between the Ex and Cont groups at 40-45 years were significant.<BR>5. Partial and whole BMDs decreased significantly with age (TBMD-Age ; r=- 0.527) . Significantly higher leg BMDs in both the 20-39-year and 40-45-year groups, and spine and TBMD in the 20-39 years in the Ex group, who were premenopausal women, were shown. No significant differences in BMDs between the two groups were observed in postmenopausal women, but the Ex group tended to have higher partial and whole BMDs. The postmenopausal official race runners (n=5.52.6-1.5years) also had higher TBMD and leg BMD values than subjects of the same ages in the Cont group.<BR>6. Investigation of correlations between VO<SUB>2</SUB>max, LTM, FTM, BMDs and serum lipid concentrations, yielded a significantly higher correlation (r=0.669) between LTM (kg) and absolute VO<SUB>2</SUB>max (1/mm) . Although VO<SUB>2</SUB>max per LTM (VO<SUB>2</SUB>max/LTM) decreased with age (r=-0.595), VO<SUB>2</SUB>max/LTM in the Ex group was significantly higher than in the Cont group in each age group. The VO<SUB>2</SUB>max per body weight (ml/kg/min) was negatively correlated with %FTM (r=-0.442) and positively correlated with
ABSTRACT
The present study was conducted to investigate the effect of acid-base disturbance on blood lactate concentration (bLA) and OBLA (Onset of Blood Lactate Accumulation) during an incremental bicycle test.<BR>Nine healthy male subjects underwent the incremental test at 60 min after the oral administration of NH<SUB>4</SUB>Cl (acidotic-treatment ; Acid), NaHCO<SUB>3</SUB> (alkalotic-treatment ; Alk) and NaCI (control ; Cont) at 1.87 mM⋅kg<SUP>-1</SUP>body weight. Exercise was started at a load of 80W, which was subsequently increased by 10W every minute until exhaustion. During exercise, O<SUP>2</SUP>intake (VO<SUP>2</SUP>), ventilatory volume (VE) and heart rate (HR) were monitored continuously. Venous blood samples were obtained before administration and every 2 min during exercise.<BR>No change could be detected in resting VO<SUB>2</SUB>, VE and HR following oral administration of NH<SUB>4</SUB>Cl, NaHCO<SUB>3</SUB>and/or NaCl. At 60 min after oral administration venous blood pH (<SUB>v</SUB>pH) and bicarbonate ion concentration (<SUB>v</SUB> [HCO<SUB>3</SUB><SUP>-</SUP>] ) were significantly lower in Acid (7.265±0.033; p <0.001, 23.6±1.8 mM⋅1<SUP>-1</SUP>; p<0.01) ; and significantly higher in Alk (7.370±0.045 ; p<0.01, 29.7±1.6 mM⋅1<SUP>-1</SUP>; p<0.01) compared to Cont (7.318±0.041, 26.6±2.1 mM⋅1<SUP>-1</SUP>) . Changes in VO<SUB>2</SUB>, VE and HR during exercise were essentially the same in all cases. No differences were observed in exercise time. During exercise, vpH and<SUB>v</SUB> [HCO<SUB>3</SUB><SUP>-</SUP>] gradually decreased, but remained significantly lower in Acid and higher in Alk compared to Cont. Blood lactate concentration (bLA) increased during exercise. Peak values were observed at exhaustion, but it was lower in Acid (8.03±1.18mM⋅1<SUP>-1</SUP>) and higher in Alk (10.73±1.48) compared to Cont (9.49±1.79) in all subjects. The Onset of Blood Lactate Accumulation (OBLA) was determined for each subject. OBLA was significantly higher in Acid (71.9±9.1%VO<SUB>2</SUB>max) than Cont (62.5±9.9%VO<SUB>2</SUB>max) and Alk (62.2±8.0%VO<SUB>2</SUB>max) .<BR>Changes in acid-base balance were found to cause differences in bLA responses to the same exercise load and possibly change OBLA. Care must be taken when using OBLA or LT as an index of aerobic capacity in some patients with acid-bace disorders; hemodialitic, obese or diabetic patient.
ABSTRACT
The present study was carried out to investigate differences in hormonal and metabolic responses to moderate exercise in the post-absorptive state and during a 33-hour fast. Secretory factors and the roles of regulatory hormones of carbohydrate and lipid metabolism during moderate exercise were assessed baesed on these data. Energy substrates in the blood (glucose, BG; lactate, LA; triglyceride, TG; free fatty acids, FFA; free glycerol, FG) and plasma hormones (ACTH; GH; Cortisol, Corti; glucagon, IRG; insulin, IRI) concentrations were measured from 12 h to 33 h during the fasting period (12: 00, 24: 00, 06: 00, 09: 00), and 3min, 10 min and 30min after moderate treadmill exercise (estimated 70-80% of VO<SUB>2</SUB>max) for 20 min under fasting conditions between 09: 00 and 11: 00. These results (in the fasting experiment, Fast) were compared to the results on a normal diet (N-D) .<BR>The results were as follows:<BR>1. No differences in mean VO<SUB>2</SUB> and respiratory exchange ratio (RER) during exercise were observed between the Fast and N-D experiments. Mean heart rate during exercise in Fast was higher by 3.3±2.2 bpm (p<0.05) .<BR>2. Serum FFA and FG concentrations were significantly higher as a results of 24-hour fasting than the values measured at the same time in N-D. No significant change in serum TG concentrations were observed in Fast. While BG and LA concentrations remained low, and in small changes occurred in then both during Fast.<BR>3. Slightly higher levels of plasma ACTH, GH and IRG were found in Fast, but they were not significantly different from N-D. Plasma Corti concentrations gradually increased after 24 hours of fasting, and were 1.9 times higher at 09: 00 after 33 hours of fasting than on N-D. Plasma IRI levels, however, remained low, and the molecular ratio of IRG to IRI (IRG/IRI) was higher throughout Fast (1.8 to 10.6 times higher than on N-D ) .<BR>4. Plasma ACTH, GH and Corti concentrations increased markedly after exercise, and remained high until 30 min on Fast. No significant change in IRG and depression of insulin secretion were demonstrated after exercise on both treatment.<BR>5. Significant correlation between changes in plasma ACTH and Corti concentrations were observed throughout the experiments (Fast, r=0.562; N-D, r=0.528) .<BR>6. All of the energy substrates except blood TG increased after exercise, and the net increases in LA and FG (Δ) on Fast were significantly higher than on N-D. Significant correlations between the changes in the concentrations of FFA and FG (Fast, r=0.745; N-D, r= 0, 696), LA and BG (Fast, r=0.689; N-D, r=0.623), and FFA and LA (Fast, r=0.579; N-D, r= 0.479) were detected throughout both experiments.<BR>7. The coefficients of correlation between changes in plasma ACTH and FFA, and between BG and LA concentrations were higher on Fast than N-D. However, changes in plasma IRI and IRG concentrations were not directly correlated with any other changes in energy substrates in the blood in either treatment.<BR>The results indicated that moderate exercise for 20 min after a 33-hour fast causes marked responses in ACTH, Corti and GH secretions. It appeared that Corti secretion de-pended on ACTH, and that Corti facilitated fatty metabolism during exercise on Fast. However, secretion factors and the role of GH during exercise remain a matter of conjecture.
ABSTRACT
A study was carried out to confirm the present states of physical training and nutritional condition in sportsmen on the growing stage. Energy expenditure (EE), caloric intake (CI), food items, body weight, running distance for 12 min and hematological and biochemical parameters of blood and urine were measured in 17 high school boys during intense summer baseball training for seven days. EE was estimated from the records by direct observation of activities during the baseball training (RMR method), and CI was calculated from the dietary record supplied each subject for the seven observation day.<BR>Following results were obtained.<BR>1) The average EE was 55.4±7.5 kcal/kg/day, and the CI corresponded to 87.2% of the EE, although no significant reduction of body weight was observed at the termination of the training session.<BR>2) Running distance for 12 min gradually decreased.<BR>3) Significant decreases in serum TG, TP and Hgb concentrations, and a remarkable increase in CPK activity were observed on the 4 th and final days. Urinary excretion of phosphate, urea nitrogen and catecholamines also increased gradually.<BR>4) The greater the increase in negative energy balance (CI-EE), the greater the decrease in TG, TP and Hgb concentrations, and the greater the increase in serum CPK and urinary excretion of catecholamines.<BR>The present results suggest that greater intake of total energy, protein and fat is recommended for development of endurance capacity, baseball techniques and sound growth in occasion such as the present baseball training program in high school boys.