Abdominal obesity is associated with arterial stiffness in middle-aged adults.

BACKGROUND AND AIMS: The relation between adiposity and arterial stiffness remains controversial. We determined whether abdominal and visceral adipose tissue may be a better predictor of arterial stiffness than general obesity in middle-aged adults. METHODS AND RESULTS: A total of 146 participants (76 men, 70 women; 50 years) were studied. The automatic vascular screening device (Omron VP-1000plus) was used to measure blood pressure simultaneously in the arms and ankles and to determine arterial stiffness by pulse wave velocity (PWV). Using multiple linear regressions, the relations between indicators of obesity and arterial stiffness were examined after adjustment for confounders. Both carotid-femoral PWV and brachial-ankle PWV were significantly associated with BMI (both P < 0.05) but not with body fat percentage. Measures of abdominal obesity, including waist circumference and visceral fat mass (via DXA), were strongly associated with PWV and remained positively associated with arterial stiffness after adjustment for age and gender. Cardiovascular fitness as assessed by maximal oxygen consumption was related to body fat percentage but not with visceral fat. More favorable cardiovascular health profile was associated with both lower visceral fat mass and PWV (both P < 0.001). CONCLUSION: Abdominal obesity and visceral fat are associated with large artery stiffness. These findings support the importance of adiposity measures as a risk factor for arterial stiffening in middle-aged adults.

Evidence for mild thyroidal impairment in women undergoing endurance training.

The effects of endurance training on body composition and the pituitary-thyroid axis were studied in 29 healthy, young (mean age, 28.7 yr), regularly menstruating women. Women who were initially jogging a mean of 13.5 miles/week were selected for this study to minimize dropouts. Body composition, measured by hydrostatic weighing, and nonfasting plasma concentrations of T4, T3, rT3, TSH, and TRH-stimulated TSH, measured by RIA, were examined initially and after each subject's weekly mileage had increased to 30 miles ( delta 30) for at least 2 consecutive weeks. Two subjects were found to have compensated primary hypothyroidism and were not included in the subsequent data analysis. At delta 30, mean body weight did not change, mean fat weight decreased (- 1.02 kg; P less than 0.005), and mean lean weight increased (+0.75 kg; P less than 0.05). T4 and unstimulated TSH did not change. However, mean (+/-SE) T3 decreased from 107.2 +/- 4.4 to 97.9 +/- 3.4 ng/dl (P less than 0.025), and mean rT3 decreased from 170.9 +/- 13.9 to 154.6 +/- 13.2 pg/ml (P less than 0.025). The decreases in T3 and rT3 were accompanied by significantly greater TSH responses to TRH stimulation [mean (+/-SE) area under TSH curve, 1381.4 +/- 123 vs. 1712.8 +/- 202 micron IU/ml.min; P less than 0.01]. These results indicate that physically active women who undergo additional endurance training 1) become more lean without a change in total weight, and 2) have changes in T3, rT3, and TRH-stimulated TSH indicative of mild thyroidal impairment.

Prolactin responses, menstrual cycles, and body composition of women runners.

Fourteen young women with normal menses participated in an endurance running program to investigate the effects of physical training on menstrual function, plasma PRL, and body composition. Body composition, measured by hydrostatic weighing, and PRL (basal and TRH-stimulated ) were determined initially and after each subject had increased her weekly mileage by 30 miles (delta 30) and 50 miles (delta 50). Mean (+/- SEM) total body weight did not change, but the subjects became significantly leaner (relative fat, 25.5 +/- 1.3% at baseline vs. 22.4 +/- 0.9% at delta 50; P less than 0.02). Thirteen women developed menstrual changes (mainly oligomenorrhea), but not amenorrhea. Mean (+/- SEM) unstimulated PRL levels were 16.8 +/- 3.1%, 16.9 +/- 2.4, and 11.5 +/- 2.1 ng/ml at baseline, delta 30, and delta 50, respectively (P less than 0.03 at delta 50 compared to baseline and delta 30). Mean ( +/- SEM) integrated TRH-stimulated PRL responses increased from 5002 +/- 462 ng/ml.min at baseline to 5748 +/- 609 mg/ml.min at delta 30 and 6535 +/- 552 ng/ml.min at delta 50, and were significantly different from one another (F = 4.01; P less than 0.04). Endurance training, without total body weight loss or extreme leanness, results in frequent menstrual dysfunction. Other authors have shown that young female athletes have an increased PRL response to acute exercise compared to nonathletes. One mechanism responsible for menstrual dysfunction in endurance-trained women may be frequent and exaggerated PRL responses to exercise and other stimuli.

Alterations in body weight and composition consequent to 20 wk of endurance training: the HERITAGE Family Study.

BACKGROUND: Obesity is a major public health problem in the United States. The role of physical activity and formal exercise in controlling body weight has not been clearly determined. OBJECTIVE: This study determined the magnitude of change in body weight and composition across sex, race, and age in response to 20 wk of endurance training. DESIGN: Men and women (n = 557) of various ages (16-65 y) and 2 races (black and white) exercised on cycle ergometers 3 d/wk for a total of 60 exercise sessions starting at 55% of maximal oxygen consumption (VO(2)max) for 30 min/session and building to 75% of VO(2)max for 50 min/session, where it was maintained during the last 6 wk. Skinfold-thickness measurements, circumferences, body composition (by hydrostatic weighing), and body fat distribution (by computed tomography scan at L4-L5 and the waist-hip ratio) were determined before and after training. RESULTS: All skinfold-thickness and circumference measures, waist-hip ratio, body mass index, total body mass, fat mass, percentage body fat, and computed tomography scan measures of total, subcutaneous, and visceral abdominal fat decreased with training, whereas total body density and fat-free mass increased. These changes were significant, but small. There were several differences in training response by sex and race, but not by age. CONCLUSIONS: A short-term exercise intervention can induce favorable changes in body composition, but the magnitude of these changes is of limited biological significance. Increasing physical activity likely has a major effect on body-composition and fat distribution characteristics only when it is of a greater magnitude and sustained for much longer periods

Alterations in resting metabolic rate as a consequence of 20 wk of endurance training: the HERITAGE Family Study.

This study determined the effects of endurance exercise training on the resting metabolic rate (RMR). It was hypothesized that the RMR would be increased posttraining, but that this increase would reflect the influence of the last exercise bout, not a chronic adaptation to exercise training. Seventy-four subjects (40 men and 37 women) aged 17-63 y participated in a 20-wk endurance training program. RMR and maximal oxygen uptake (VO2max) were each measured on 2 separate days both pre- and posttraining; the posttraining RMR measurements were taken 24 and 72 h after the last exercise bout. There were small but significant changes posttraining in relative body fat (-1.0%), fat mass (-0.6 kg), and fat-free mass (0.7 kg) and a 17.9% increase in VO2max. The RMR remained unchanged posttraining, both 24 and 72 h after the last exercise bout, even when the data were adjusted to account for the potential confounding effects of age, sex, body composition, and VO2max. In conclusion, 20 wk of endurance exercise training had no effect on the RMR even in the presence of small changes in body composition and a large increase in VO2max.

Reproducibility of resting blood pressure and heart rate measurements. The HERITAGE Family Study.

PURPOSE: This study determined the reproducibility of resting systolic and diastolic blood pressure, mean arterial pressure, and heart rate (the average of three measures/day). METHODS: The data were obtained on two separate days prior to an exercise training intervention in a sample of 822 subjects participating in the HERITAGE Family Study. The same protocol was conducted across three days in an intracenter quality control substudy, which included an additional 60 subjects. RESULTS: Reproducibility estimates included technical error, coefficient of variation within subjects, and intraclass correlation with results expressed by sex, race, age, cuff size, BMI, and %fat. Since the data were collected across four Clinical Centers, the reproducibility estimates were also computed separately for each Center. The systolic, diastolic, and mean arterial blood pressures were highly reproducible with technical errors less than 5.1 mmHg, coefficients of variation of less than 7. 0% and intraclass correlations > 0.75. The heart rates were slightly less reproducible. These results were fairly consistent across subject populations and across all four Clinical Centers. CONCLUSION: It is concluded that within subject day-to-day variations are small compared to between subject variance for resting systolic, diastolic, and mean arterial blood pressure and heart rate at each of the Clinical Centers for all of the HERITAGE Family Study data. This makes it appropriate to pool the data and analyze it for changes subsequent to endurance exercise training and to determine the possible genetic basis for these changes.

High density lipoprotein cholesterol and body composition of female runners.

Twenty-two women participating in an endurance running program had determinations of body composition, of plasma total cholesterol (TC) and HDL cholesterol (HDLC) concentrations before and after increasing their running by 30 miles/wk. Mean total body weight, fat weight and relative body fat showed significant decreases, while mean lean weight significantly increased. Mean HDLC increased 5 mg/dl (p less than 0.01). Although increases of HDLC correlated with increases in lean weight, exercise per se appears to increase HDLC of women.

Relationship of changes in maximal and submaximal aerobic fitness to changes in cardiovascular disease and non-insulin-dependent diabetes mellitus risk factors with endurance training: the HERITAGE Family Study.

The purpose of this study was to determine the relationship between changes in maximal oxygen uptake (VO2 max) and submaximal markers of aerobic fitness and changes in risk factors for cardiovascular disease (CVD) and non-insulin-dependent diabetes mellitus (NIDDM) consequent to a 20-week endurance training program. The 502 participants in this study were healthy and previously sedentary men (n = 250) and women (n = 252) of varying age (17 to 65 years) and race (blacks n = 142; whites n = 360) who had completed the HERITAGE Family Study testing and training protocol. Following baseline measurements, participants trained on cycle ergometers 3 days/week for a total of 60 exercise sessions starting at the heart rate (HR) associated with 55% of VO2 max for 30 minutes/session. This was progressively increased to the HR associated with 75% of VO2 max for 50 minutes/session, which was maintained during the last 6 weeks. VO2 max, heart rate at 50 W, power output at 60% of VO2 max, lipids and lipoproteins, resting blood pressure, body composition including abdominal fat (computed tomography [CT] scan), and blood glucose and insulin at rest and at peak following an intravenous glucose tolerance test (IVGTT) were determined both before and after training. Following training, there were significant increases in VO2 max (16%) and the power output at 60% of VO2 max and a significant decrease in HR at 50 W. These changes in markers of aerobic fitness were significantly correlated only to the changes in the body composition variables and the lipids and lipoproteins. Further, there was considerable individual variation in response for all variables studied. Finally, when risk factor data were analyzed by quartile of change in VO2 max, there were few significant relationships. It is concluded that there is a significant relationship between changes in markers of aerobic fitness and changes in several risk factors for CVD and NIDDM. However, the magnitude of these relationships is small.

Sex steroids and endurance running in women.

The effects of endurance training on body composition, menstrual cycles, and sex steroids were studied in 19 healthy, regularly menstruating women. Body composition and midfollicular plasma concentrations of estradiol (E2), estrone (E1), and testosterone (T) were examined at baseline and after each subject's weekly mileage had increased 30 miles (delta 30) and 50 miles (delta 50) above baseline. Total body weight did not change, but the subjects became leaner. Mean +/- standard error of the mean E2 decreased from 70.6 +/- 13.9 pg/ml at baseline to 33.6 +/- 4.8 pg/ml at delta 50 (P = 0.03). Mean E1 decreased progressively, but not significantly, while T did not change. Eighteen women developed menstrual changes (mainly oligomenorrhea), but not amenorrhea. Endurance running in women results in frequent menstrual dysfunction and is associated with a significant decrease in E2 concentrations.

Impaired gonadotropin responses to gonadotropin-releasing hormone stimulation in endurance-trained women.

The effects of endurance running on body composition, menstrual cycles, and gonadotropins were studied in 19 healthy, young, regularly menstruating women. Midfollicular plasma concentrations of unstimulated and gonadotropin-releasing hormone (GnRH)-stimulated luteinizing hormone and follicle-stimulating hormone were examined at baseline and after each subject's weekly mileage had increased 30 miles (delta 30) and 50 miles (delta 50) above baseline. Mean +/- standard error of the mean unstimulated luteinizing hormone and follicle-stimulating hormone did not change significantly. GnRH-stimulated luteinizing hormone was 76.3 +/- 22.0 micrograms/min/ml at baseline and declined to 20.2 +/- 4.5 micrograms/min/ml at delta 50 (P less than 0.02). GnRH-stimulated follicle-stimulating hormone was 28.4 +/- 7.0 micrograms/min/ml at baseline and declined to 9.6 +/- 2.1 micrograms/min/ml at delta 50 (P less than 0.02). There were no significant correlations between changes in body composition and changes in gonadotropin responses. Eighteen subjects developed oligomenorrhea.

Thyroidal changes associated with endurance training in women.

The associations between endurance training, body composition, and the pituitary-thyroid axis were studied in 17 healthy, young women. Body composition and plasma concentrations of T4, T3, rT3, resin T3 uptake, TSH, and TRH-stimulated TSH were examined at baseline and after each subject's weekly distance had increased 48 km (delta 48) and 80 km (delta 80) above baseline. Total body weight did not change at delta 48 or delta 80. Mean (+/- SE) lean weight in kg increased from 42.9 +/- 1.2 at baseline to 44.8 +/- 1.2 at delta 80 (P = 0.002). We have reported previously that at delta 48 the subjects had evidence of mild thyroidal impairment, which consisted of decreased T3 and rT3, and an exaggerated TSH response to TRH. With more prolonged training (delta 48 to delta 80) there were significant increases in T4, rT3, and unstimulated TSH, while the ratios of T4/rT3 and T3/rT3 and the TSH response to TRH decreased significantly. Some of the thyroidal changes that occurred between delta 48 and delta 80 are similar to those seen in other stressful non-thyroidal conditions.

Heart rate and blood pressure changes with endurance training: the HERITAGE Family Study.

PURPOSE: The purpose of this study was to determine the magnitude of change in resting and exercise heart rate (HR) and blood pressure (BP), by race, sex, and age, after a 20-wk endurance training program in 507 healthy and previously sedentary subjects from the HERITAGE Family Study. METHODS: After baseline measurements, subjects exercised on cycle ergometers 3 d x wk(-1) for a total of 60 exercise sessions starting at 55% of VO2max for 30 min x session(-1) and building to 75% of VO2max for 50 min x session(-1) for the last 6 wk. HR and BP at rest and during exercise (50 W, 60% of VO2max maximal exercise) were each determined in duplicate on two different days both before and after training (resting values at 24-h and 72-h posttraining). RESULTS: After the period of training, there was a small decrease in resting HR (-2.7 to -4.6 beats x min(-1) across groups at 72-h posttraining), and small changes (i.e., < 3 mm Hg) in resting systolic (SBP), diastolic (DBP), and calculated mean BP (MBP), which varied by race, sex, and age. During exercise at the same absolute work rate (50 W), HR, SBP, DBP, and MBP were all significantly reduced, with greater reductions in HR in women compared with men, and greater reductions in BP in blacks and older subjects compared with whites and younger subjects, respectively. At the same relative work rate (60% VO2max), HR, DBP, and MBP were reduced, but SBP remained unchanged. Blacks had a greater reduction in DBP, but whites had a greater reduction in HR. Finally, at maximal exercise, there was a small decrease in HR, with men and whites decreasing more than women and blacks; an 8 mm Hg increase in SBP, with men increasing more than women; a 4 mm Hg decrease in DBP, with blacks decreasing more than whites; and no change in MBP. CONCLUSION: In conclusion, the reductions in resting HR and BP with training were generally small, but the reductions during exercise were substantial and clinically important, with the older and the black populations experiencing greater reductions.

Cardiac output and stroke volume changes with endurance training: the HERITAGE Family Study.

PURPOSE: The purpose of this study was to determine the magnitude of changes in cardiac output (Qc), stroke volume (SV), and arterial-mixed venous oxygen difference (a-vO2 diff) during submaximal exercise following a 20-wk endurance training program, with the primary focus on identifying differences in response by race, sex, and age. METHODS: The participants in this study (N = 631) were healthy and previously sedentary men (N = 277) and women (N = 354) of varying age (17-65 yr) and race (blacks, N = 217; whites, N = 414) who had completed the HERITAGE Family Study protocol. After baseline measurements, participants trained on cycle ergometers 3 d x wk(-1) for a total of 60 exercise sessions starting at the HR associated with 55% of maximal oxygen uptake (VO2max) for 30 min/session and building to the HR associated with 75% of VO2max for 50 min/session, which was maintained during the last 6 wk. HR, Qc (CO2 rebreathing), and SV (Qc/HR) were determined in duplicate at 50 W and at 60% of VO2max on two different days both before and after training. RESULTS: After training, there were significant decreases in HR and Qc, and significant increases in SV and a-vO2 diff at 50 W (except for no change in a-vO2 diff in black men). The changes in HR differed by sex and age, and the changes in SV, Qc, and a-vO2 diff differed by race. Qc decreased by 0.6 L x min(-1) at 50 W for the total sample, consistent with the decrease in VO2 at this power output. At 60% of VO2max HR decreased, and SV, Q, and a-VO2 diff increased. There were small differences in response by sex (HR and SV), race (HR), and age (HR and Qc). CONCLUSION: It is concluded that the cardiovascular systems of men and women, blacks and whites, and younger and older subjects are not limited in their ability to adapt to endurance training.

Reproducibility of cardiovascular, respiratory, and metabolic responses to submaximal exercise: the HERITAGE Family Study.

This study determined the reproducibility of cardiovascular, respiratory, and metabolic responses to submaximal cycle ergometer exercise at two power outputs (50 W and 60% VO2max) on each of two separate days in a sample of 390 subjects (198 men and 192 women) participating in the HERITAGE Family Study. The same protocol was conducted across 3 d in an intracenter quality control substudy which included an additional 55 subjects. Reproducibility estimates included technical error, coefficient of variation, and intraclass correlation for each of the selected variables for both subject populations. Further, since the data were collected across four clinical centers, intraclass correlations were also computed separately by clinical center. Most variables were highly reproducible, with coefficients of variation below 9% and intraclass correlations over 0.80. These results were consistent for both subject populations and across all four clinical centers. Reproducibility indicators were generally better at the higher power output. It is concluded that within-subject day-to-day variation and measurement unreliabilities are generally small compared with the between-subject variance in the response to submaximal exercise at each of the clinical centers of the HERITAGE Family Study.

Mechanical and physiological calibration of four cycle ergometers.

Mechanical and physiological calibrations were performed on four research-grade cycle ergometers. Ten subjects rode each ergometer twice in a randomized testing order. The subjects pedaled at 60 rpm for 5 min at each of three power outputs, i.e., 49, 98, and 147 W. Heart rate, metabolic, and perceptual data were obtained each minute. Prior to and immediately following these test rides, mechanical calibrations were obtained in duplicate. From the mechanical calibrations, Ergometer A was approximately 10% below actual values at each power output. Ergometer B demonstrated a variable error, with the largest percentage and absolute errors occurring at the lower power outputs. Ergometers C and D generally demonstrated less than a +/- 3% error. Following the physiological calibration, Ergometer B exhibited a substantial drift in calibration, while Ergometers A, C, and D maintained their original calibration. The physiological data supported the mechanical calibration, and Ergometer B demonstrated a substantial drift between the first and second trials and produced substantially different results compared with the other three ergometers. Ergometers A, C, and D demonstrated acceptable consistency in results both within trials and among ergometers. These results demonstrate the importance of proper calibration and of understanding the calibration characteristics of ergometers selected for research purposes.

Endurance exercise training has a minimal effect on resting heart rate: the HERITAGE Study.

This study determined the effects of a 20-wk endurance training program (The HERITAGE Family Study) on resting heart rate (HRrest). HRrest was obtained on a sample of 26 men and 21 women during sleep; during resting metabolic rate and resting blood pressure measurement periods in the early morning following a 12-h fast and 24-h post-exercise; and at rest prior to a maximal bout of exercise. Following training, the subjects exhibited a 16.0 +/- 9.4% (mean +/- SD) increase in VO2max (P < 0.05), but the HRrest for each of the resting conditions was decreased by only 1.9 to 3.4 bpm (P < 0.05), or an average across the three conditions of 2.7 bpm. In a larger sample of 253 HERITAGE subjects, HRrest obtained only at the time of the resting blood pressure measurement decreased by only 2.6 bpm, while VO2max increased 17.7 +/- 10.0%. It is concluded that there is a significant, but small, decrease in resting heart rate as a result of 20 wk of moderate- to high-intensity endurance training; which suggests a minimal alteration in either, or both, intrinsic heart rate and autonomic control of HRrest.

The effect of an acute bout of exercise on selected pulmonary function measurements.

The purpose of this study was to determine and follow the effect of an acute bout of exercise on residual volume (RV) and other pulmonary function measurements over a 24-h post-exercise period, and to evaluate the effect on subsequent body composition calculations. Selected pulmonary function measurements of 12 male college students were collected prior to exercise at 5, 15, and 30 min, and at 1, 2, and 24 h post-exercise. RV was significantly (P less than 0.01) increased 20.8% (260 ml), 16.8% (210 ml) and 12.0% (150 ml) at 5, 15, and 30 min post-exercise, respectively. Total lung capacity (TLC) was significantly (P less than 0.01) increased 2.7% (190 ml) and 2.3% (160 ml) at 5 and 15 min post-exercise, respectively. Subsequent body composition calculations, using the post-exercise RV data, resulted in significantly (P less than 0.01) lower relative body fat measures, as compared to the pre-exercise value, through 30 min of recovery. In conclusion, our data demonstrate apparent increases in RV and TLC immediately following maximal treadmill exercise; these measurements remained significantly increased over pre-exercise values, through 30 and 15 min of recovery, respectively. It is recommended that the RV measurement and the actual hydrostatic weighing procedure not be separated by an acute bout of exercise, and that protocols for long-term studies be standardized.

Accuracy of prediction equations to estimate submaximal VO2 during cycle ergometry: the HERITAGE Family Study.

UNLABELLED: It was hypothesized that more accurate equations for estimating submaximal VO2 during cycle ergometry could be developed if more independent variables were used in the equation. PURPOSE: The purposes of this study were: (1) to develop new equations for estimating submaximal VO2 during cycle ergometry; and (2) to examine the accuracy of the newly developed equations and those of the American College of Sports Medicine (1995), Berry et al. (1993), Lang et al. (1992), Latin and Berg (1994), and Londeree et al. (1997). METHODS: Subjects (715 men and women, ages 16-65 yr, from the HERITAGE Family Study) completed a maximal cycle ergometry test, two submaximal trials at 50 W and 60% of VO2max, hydrostatic weighing, and stature and body mass measures before and after 20 wk of cycle ergometry training. Regression analysis generated prediction equations using pretraining data from the 60% trials. RESULTS: No equation with more independent variables was better than an equation that used only power output. This equation, HERITAGE-1, with only power output was cross-validated using the "jackknife" technique. Paired t-tests, mean differences, SEEs, and Es were used to compare the VO2 estimated by HERITAGE-1 and those of previously published equations with the measured VO2 at 60% of VO2max. CONCLUSIONS: HERITAGE-1 was slightly better than the equations of ACSM, Lang et al., and Latin and Berg using pretraining data but was not better when using post-training data. All four of these equations were superior to the equations of Berry et al. and Londeree et al.

Alterations in plasma lipids consequent to endurance training and beta-blockade.

Alterations in plasma lipids consequent to endurance training and beta-blockade. Med. Sci. Sports Exerc., Vol. 21, No. 3, pp. 288-292, 1989. The chronic use of beta adrenergic blockers (BAB) has been associated with reductions in HDL-cholesterol (HDL-C) and increases in triglycerides (TG). This study evaluated the impact of concurrent endurance exercise training and chronic medication with BAB on plasma lipid and lipoprotein profiles in healthy young adult males. Changes in plasma lipids and lipoproteins were investigated while exercise training under the influence of one of two nonselective BAB [sotalol (320 mg.d-1) and propranolol (160 mg.d-1)], one beta 1 selective BAB [atenolol (100 mg.d-1)], or a placebo control. Total cholesterol (TC), HDL-C, LDL-cholesterol (LDL-C), TG, and the ratios of TC/HDL and LDL/HDL were determined before and after endurance training programs of either 14 (N = 27, sotalol) or 15 (N = 47, propranolol/atenolol) wk duration. The subjects exhibited increases in maximal oxygen uptake of 12-20%. Despite increased endurance capacity, the subjects in both BAB and placebo control groups failed to demonstrate the expected increase in HDL-C and decrease in TG. In fact, HDL-C was significantly decreased post-training in the propranolol group. The placebo groups did decrease TC, LDL-C and the TC/HDL and LDL/HDL ratios, improving their CHD risk profile. Similar changes were not observed in the groups on BAB. Thus, with respect to the present population, BAB does appear to interfere with the usual training-induced improvements in the lipid profile. Endurance training may, however, reduce the deterioration in the lipid profile known to occur with BAB.

Ratings of Perceived Exertion, Heart Rate, and Power Output in Predicting Maximal Oxygen Uptake During Submaximal Cycle Ergometry.

In brief: Sixty-two subjects completed a four- stage submaximal cycle ergometer test to volitional fatigue. The purpose was to determine if estimates of V O2 max could be improved by using ratings of perceived exertion singly or in combination with easily obtainable physiological measures during submaximal cycle ergometry. While these procedures may not be acceptable for scientific purposes, clinicians could use them to estimate the aerobic power of their patients and athletes.