Maternal and neonatal outcomes for pregnancies before and after gastric bypass surgery.

BACKGROUND: Interaction between maternal obesity, intrauterine environment and adverse clinical outcomes of newborns has been described. METHODS: Using statewide birth certificate data, this retrospective, matched-control cohort study compared paired birth weights and complications of infants born to women before and after Roux-en-Y gastric bypass surgery (RYGB) and to matched obese non-operated women in several different groups. Women who had given birth to a child before and after RYGB (group 1; n=295 matches) and women with pregnancies after RYGB (group 2; n=764 matches) were matched to non-operated women based on age, body mass index (BMI) prior to both pregnancy and RYGB, mother's race, year of mother/s birth, date of infant births and birth order. In addition, birth weights of 13 143 live births before and/or after RYGB of their mothers (n=5819) were compared (group 3). RESULTS: Odds ratios (ORs) for having a large-for-gestational-age (LGA) neonate were significantly less after RYGB than for non-surgical mothers: ORs for groups 1 and 2 were 0.19 (0.08-0.38) and 0.33 (0.21-0.51), respectively. In contrast, ORs in all three groups for risk of having a small for gestational age (SGA) neonate were greater for RYGB mothers compared to non-surgical mothers (ORs were 2.16 (1.00-5.04); 2.16 (1.43-3.32); and 2.25 (1.89-2.69), respectively). Neonatal complications were not different for group 1 RYGB and non-surgical women for the first pregnancy following RYGB. Pregnancy-induced hypertension and gestational diabetes were significantly lower for the first pregnancy of mothers following RYGB compared to matched pregnancies of non-surgical mothers. CONCLUSION: Women who had undergone RYGB not only had lower risk for having an LGA neonate compared to BMI-matched mothers, but also had significantly higher risk for delivering an SGA neonate following RYGB. RYGB women were less likely than non-operated women to have pregnancy-related hypertension and diabetes.

Action of cholecystokinin and cholinergic agents on calcium transport in isolated pancreatic acinar cells.

COOH-terminal octapeptide of cholecystokinin (CCK-octapeptide) and the cholinergic agent carbamylcholine each produced a fourfold stimulation of calcium outflux in guinea pig isolated pancreatic acinar cells. Neither agent altered calcium influx. Stimulation of calcium outflux was rapid and specific, was abolished by reducing the incubation temperature to 4 degrees C, and was a saturable function of the secretagogue concentration. The concentrations of CCK-octapeptide and carbamylcholine that produced half-maximal stimulation of calcium outflux were 3.1 x 10(-10) M and 4.9 x 10(-5) M, respectively. The cholinergic antagonist antropine competitively inhibited carbamylcholine stimulation of calcium outflux but did not alter stimulation produced by CCK-octapeptide. Stimulation of calcium outflux by maximal concentrations of carbamycholine plus CCK-octapeptide was the same as that produced by a maximal concentration of either agent alone.Calcium outflux became refractory to stimulation by secretagogues, and incubation with either CCK-ostapeptide or carbamylcholine produced a refractoriness to both agents. The relative potencies with CCK and its related fragments stimulated calcium outflux were CCK-octapeptide greater than heptapeptide greater than CCK greater than hexapeptide = gastrin. Secretin, glucagon, and vasoactive intestinal peptide, at concentrations as high as 10(-5) M, failed to alter calcium outflux and did not affect stimulation by CCK-octapeptide or by carbamycholine.

Cardiorespiratory fitness and coronary heart disease risk factors: the LDS Hospital Fitness Institute cohort.

BACKGROUND: Cardiorespiratory fitness is favorably associated with most modifiable coronary heart disease (CHD) risk factors. Findings are limited, however, by few data for women, persons with existing CHD, and low-risk populations. In the present study, we described cross-sectional associations between cardiorespiratory fitness and CHD risk factors in a large cohort of middle-aged men and women, of whom the majority were LDS Church members (Mormons), with and without existing CHD. METHODS AND RESULTS: Comprehensive health examinations were performed on 3232 men (age 45.9+/-10.8 years) and 1128 women (age 43.8+/-12.8 years) between 1975 and 1997. Maximal treadmill exercise testing was used to categorize those with (12% of the men and 10% of the women) and those without CHD into age- and sex-specific cardiorespiratory fitness quintiles. After adjustments for age, body fat, smoking status, and family history of CHD, favorable associations were observed between fitness and most CHD risk factors among men and women, regardless of CHD status. CONCLUSIONS: These data indicate that enhanced levels of cardiorespiratory fitness may confer resistance to elevations in CHD risk factors even in a low-risk sample of middle-aged men and women. Furthermore, these findings reinforce current public health recommendations that advocate increased national levels of physical activity and cardiorespiratory fitness for primary and secondary CHD prevention.

Noninvasive evaluation of world class athletes engaged in different modes of training.

This study evaluated by noninvasive methods the cardiac structure and functional characteristics of world class athletes participating in different types of training programs. Fourteen subjects, including 4 strength-trained (discus and shot put), 4 endurance-trained (long distance runners), 4 decathlon-trained (strength and endurance), 2 wheelchair athletes and 31 college-age control subjects were evaluated using electrocardiography, M-mode echocardiography and maximal oxygen consumption. M-mode echocardiography measurements of left ventricular structure and function were compared before and after normalization for lean body weight. As expected, endurance athletes had greater maximal O2 consumption than the other groups (p less than 0.05). Before normalization for lean body weight, there were no significant differences in end-diastolic dimensions. After normalization, the endurance, wheelchair and control subjects had end-diastolic dimensions larger than those of strength athletes. Strength athletes appeared to have a much larger posterior wall and septal thickness than all groups except the decathlon athletes. However, when normalized, there was no difference among any of the groups. Previous investigators have attempted to determine "normalcy" of cardiac hypertrophy by looking at the ratio of left ventricular wall thickness to left ventricular radius. In the present study, the thickness to radius ratio in strength athletes was 33% greater than that in endurance athletes. It appears that the left ventricular wall thickness in the strength athletes occurred without a concomitant increase in left ventricular radius and that the left ventricular hypertrophy of world class athletes is related to the total increase in lean body weight. However, ventricular dimensions may be related more to the type of overload experienced.

Heritability estimates of pulmonary function.

To test the hypothesis that there is genetic control of pulmonary function parameters independent of that influencing height, we evaluated 74 pairs of asymptomatic, nonsmoking twins. FVC, FEV1, FEF25-75%, TLCsb, RVsb, Dsb, and D/VA were measured. Pulmonary function indices were adjusted for height using simple linear regression. Mean intrapair differences (unadjusted and adjusted for height) were compared using t tests of independent samples. Within pair, Holzinger's, and Falconer's heritability estimates were calculated using height-adjusted residual values. When total variances of a function parameter were statistically different between monozygotes and dizygotes, the among component heritability estimate was calculated and used as the best indicator of heritability. Following adjustment for height, no measure of pulmonary function which satisfied the requirements of the analysis was found to be significantly heritable.

Turbine flowmeter vs. Fleisch pneumotachometer: a comparative study for exercise testing.

The purpose of this study was to investigate the characteristics of a newly developed turbine flowmeter (Alpha Technologies, model VMM-2) for use in an exercise testing system by comparing its measurement of expiratory flow (VE), O2 uptake (VO2), and CO2 output (VCO2) with the Fleisch pneumotachometer. An IBM PC/AT-based breath-by-breath system was developed, with turbine flowmeter and dual-Fleisch pneumotachometers connected in series. A normal subject was tested twice at rest, 100-W, and 175-W of exercise. Expired gas of 24-32 breaths was collected in a Douglas bag. VE was within 4% accuracy for both flowmeter systems. The Fleisch pneumotachometer system had 5% accuracy for VO2 and VCO2 at rest and exercise. The turbine flowmeter system had up to 20% error for VO2 and VCO2 at rest. Errors decreased as work load increased. Visual observations of the flow curves revealed the turbine signal always lagged the Fleisch signal at the beginning of inspiration or expiration. At the end of inspiration or expiration, the turbine signal continued after the Fleisch signal had returned to zero. The "lag-before-start" and "spin-after-stop" effects of the turbine flowmeter resulted in larger than acceptable error for the VO2 and VCO2 measurements at low flow rates.

Ventilatory control during exercise in calves with artificial hearts.

To determine the role of cardiac reflexes in mediating exercise hyperpnea, we investigated ventilatory responses to treadmill exercise in seven calves with artificial hearts and seven controls. In both groups, the ventilatory responses were adequate for the metabolic demands of the exercise; this resulted in regulation of arterial PCO2 and pH despite the absence of cardiac output increase in the implanted group. In this group, there was a small but significant reduction of arterial PO2 by 4 +/- 3 Torr and a rise of blood lactate by 1.1 +/- 1 mmol/l. When cardiac output was experimentally increased in the implanted calves to a level commensurate with that spontaneously occurring in the control calves, ventilation was not affected. However, experimental reductions of cardiac output led to an immediate augmentation of exercise hyperpnea by 4.56 +/- 4.3 l/min and a further significant lactate increase of 1.2 +/- 1.22 mmol/l that was associated with a significant decrease in the exercise O2 consumption (0.32 +/- 0.13 l/min). These observations indicate that neither cardiac nor hemodynamic effects of increased cardiac output constitute an obligatory cause of exercise hyperpnea in the calf.

Functional status and emotional well-being, dietary intake, and physical activity of severely obese subjects.

OBJECTIVE: Analyze functional status and emotional well-being, energy and nutrient intake, and physical activity in sibling pairs raised together in the same family. DESIGN: One sibling classified as severely obese (body mass index > or = 35) and the other sibling as normal weight (body mass index < or = 27). SUBJECTS: From January 1994 through December 1996 at the Cardiovascular Genetics Research Clinic of the University of Utah School of Medicine, 145 sibling pairs (n = 290) were selected from a population-based, family history database or a hospital-based, very-low-energy weight-loss program. STATISTICAL ANALYSIS PERFORMED: Repeated-measures analysis of variance tested for differences between severely obese and normal-weight siblings. RESULTS: All functional status and emotional well-being scores (poorer perceived health) were significantly lower in severely obese siblings compared with normal-weight siblings. The severely obese siblings had a higher percentage dietary fat intake (3% higher) and total energy intake (more than 350 kcal higher), and lower weight-adjusted total energy intake (almost 10 kcal/kg lower) and activity energy expenditure (3.5 kcal/kg lower), compared with normal-weight siblings. Thus, environmental influences such as energy and nutrient intake and physical activity are highly related to severe obesity. APPLICATIONS: Previously shared environment of severely obese and normal-weight siblings raises questions about whether strong environmental influences or genetic predisposition account for the differences in sibling weight. When counseling individuals or families with a history of severe obesity, dietetics practitioners should be familiar with the potential for strong genetic factors and related environmental influences. In addition, dietitians should be prepared to offer a flexible approach to physical exercise as well as provide additional behavioral support.

Bioelectric impedance and hydrostatic weighing with and without head submersion in persons who are morbidly obese.

OBJECTIVE: To compare hydrostatic weighing with and without head submersion and bioelectric impedance analysis (BIA) for measurement of body composition of persons who are morbidly obese. DESIGN: Body composition was determined using 3 methods: hydrostatic weighing with and without head submersion and BIA. Residual volume for the hydrostatic weighing calculation was determined by body plethysmography. SUBJECTS: Subjects were 16 morbidly obese men (142.5 kg mean body weight) and 30 morbidly obese women (125.9 kg mean body weight) living in the Salt Lake County, Utah, area. Morbid obesity was defined as 40 kg or more over ideal weight. STATISTICAL ANALYSIS: One-way, repeated-measures analysis of variance was followed by Scheffé post hoc tests; body-fat measurement method served as the repeated variable and percentage of body fat as the dependent variable. Men and women were analyzed separately. In addition, degree of agreement between the 3 methods of determining body composition was determined. A regression equation was used to calculate body density for hydrostatic weighing without head submersion. Two new BIA regression equations were developed from the data of the 16 men and 30 women. RESULTS: Values for percentage body fat from hydrostatic weighing with and without head submersion (41.8% vs 41.7%, respectively) were the same for men but differed for women (52.2% vs 49.4%, respectively, P < .0001). Values for body fat percentage measured by BIA were significantly lower for men (36.1%) and women (43.1%) (for both, P < .0001) compared with values from hydrostatic weighing methods. BIA underpredicted percentage body fat by a mean of 5.7% in men and 9.1% in women compared with the traditional hydrostatic weighing method. APPLICATIONS/CONCLUSIONS: BIA tended to underpredict the measurement of percentage body fat in male and female subjects who were morbidly obese. Hydrostatic weighing without head submersion provides an accurate, acceptable, and convenient alternative method for body composition assessment of the morbidly obese population in comparison with the traditional hydrostatic weighing method. In population screening or other settings where underwater weighing is impractical, population-specific BIA regression equations should be used because general BIA equations lead to consistent underprediction of percentage body fat compared with hydrostatic weighing.

My gay Antonia: the politics of Willa Cather's lesbianism.

Although Willa Cather's lesbianism has recently been publicly acknowledged, her personal and artistic political decisions about the revelation of her sexual preference have not been explored. Most critics who acknowledge Cather's homosexuality see no traces in her fiction of what Lillian Faderman calls "same-sex love." Because of the political consequences of writing openly about lesbianism in the time that Cather came of age, according to Faderman, "perhaps she felt the need to be more reticent about love between women than even some of her patently heterosexual contemporaries because she bore a burden of guilt for what came to be labeled perversion." While it would certainly have been possible for Cather to live a discreet lesbian life without showing traces of her sexuality in her writing, it is more likely that her sexual preferences are present in her works, particularly in her most autobiographical book, My Antonia, in the character who represents Cather, Jim Burden. The "emptiness where the strongest emotion might have been expected," the relationship between Antonia and Jim, is more understandable when we realize that both Jim Burden and Antonia Shimerda were imagined by Cather as homosexuals whose deep friendship was based on mutual understanding of their oddness in the heterosexual world of 1918.

The relationship between body mass index and per cent body fat in the severely obese.

BACKGROUND: International standards define clinical obesity according to body mass index (BMI) without reference to age and gender. Recent studies among adults in the normal to mildly obese BMI ranges have shown that the relationship between BMI and per cent body fat (% fat) differs by age and gender. The extent to which age and gender affect the relationship between BMI and % fat among more severely obese individuals is less known. AIM: The aim was to examine the age-gender association between measured BMI and % fat from a large cohort of adults, including a large number of severely obese subjects (1862 with a BMI > or = 35 kg/m(2)). METHODS: BMI was computed from measured height and weight, and % fat was estimated from bioelectrical impedance in 3068 adults. Two impedance equations, the Sun equation and the Heath equation (specific to severe obesity), were used to calculate % fat. RESULTS: Average age for 991 men and 2077 women was 46 +/- 15 vs. 44 +/- 14 years respectively (p = 0.0003). The average BMI was 36 +/- 9 kg/m(2) for men and 39 +/- 10 kg/m(2) for women (p < 0.0001), with a combined gender BMI range of 19-74 kg/m(2). Using the Sun equation, average % fat was 31 +/- 8 vs. 46 +/- 8% (p < 0.0001) for all men and women respectively. With the Sun equation, age-adjusted Spearman correlations between all BMI and % fat values were r = 0.80 and r = 0.83 for men and women, respectively, but only 0.60 (n = 479) and 0.61 (n = 1383) in severely obese participants (BMI > or = 35 kg/m(2)). Using the Heath equation, only for participants with BMI > or = 35 kg/m(2), the age-adjusted Spearman correlations improved to r = 0.82 (n = 479) and r = 0.70 (n = 1383) for men and women respectively. Finally, by combining the Sun equation for subjects with BMI < 35 kg/m(2) and the Heath equation for those with BMI > or = 35 kg/m(2), correlations improved to 0.89 for men and 0.87 for women. Using these combined equations, the relationship between BMI and % fat was best fit as a linear function for men and curvilinear function (both p < 0.001) for women across the range of BMI. The % fat was approximately 10% higher for any BMI value among women vs. men even among the severely obese (p < 0.0001). CONCLUSIONS: These data that include a large cohort of severely obese individuals demonstrated a linear association between BMI and % fat for men and a curvilinear association between BMI and % fat for women when Sun and Heath equations were combined. Assuming disease risk is driven by adiposity, this study suggests a need to further explore the appropriateness of gender-specific BMI cutpoints for clinical risk assessment due to the marked difference in the BMI-per cent fat relation observed in men and women across the entire range of BMI.

Biochemical and anthropometric characterization of morbid obesity in a large Utah pedigree.

A Utah family with morbid obesity was extended to include 122 persons in four generations for the purpose of characterizing anthropometric and biochemical variables in family members with and without morbid obesity. Seventy-seven subjects had blood drawn for biochemical analyses. Of the 77 subjects, 12 were morbidly obese (> or = 44.5 kg or 100 pounds overweight), 20 were between 22.5-45.4 kg (50 and 99 pounds) overweight and 45 were less than 22.5 kg (50 pounds) overweight. Sixty-two randomly-ascertained controls were used for comparisons of age- and gender-adjusted study variables. Morbidly obese subjects had mean body mass indices (BMI) of 41.0 kg/m2 (62 kg over ideal weight) compared to 25.3 kg/m2 (10 kg overweight) in the < 22.5 kg family members (p < 0.001). The < 22.5 kg family members had lower BMI than the random controls (27.6 kg/m2, p < 0.05), indicating clear bimodality of obesity within the pedigree. Percent body fat from bioelectrical impedance was 35% versus 24% in the morbidly obese and the < 22.5 kg subjects, respectively. Idealbody weight was similar among the three pedigree weight groups. Hip and waist circumferences were much larger in the morbidly obese and the waist-to-hip ratio remained significantly greater in the morbidly obese subjects compared to the < 22.5 kg group. Morbidly obese subjects had elevated triglycerides and VLDL-C levels, low HDL-levels, and normal LDL-C levels. Fasting insulin was the best predictor of morbid obesity of all biochemical and lipid measurements (odds ratio of 4.5). Fasting insulin levels and the insulin-to-glucose ratio were more than twice as high as control levels.(ABSTRACT TRUNCATED AT 250 WORDS)

Cyclic AMP in pancreatic acinar cells: effects of gastrointestinal hormones.

In the presence of 5 mM theophylline, secretin and vasoactive intestinal peptide (VIP) each increased cyclic adenosine 3':5'-monophosphate (cyclic AMP) in acinar cells isolated from guinea pig pancreas. Without theophylline, neither peptide altered cellular cyclic AMP. Glucagon, which is similar to secretin and VIP both in chemical structure and spectrum of biologic activities, neither stimulated cellular cyclic AMP nor inhibited the stimulation produced by secretin or by VIP. Other agents which were tested and found not to increase cellular cyclic AMP were cholecystokinin, carboxyl-terminal octapeptide of cholecystokinin, gastrin I, gastrin II, bovine pancreatic polypeptide, carbamylcholine, and prostaglandin E1. Neither carboxyl-terminal octapeptide nor gastrin I altered the stimulation of cellular cyclic AMP produced by secretin or VIP. With natural secretin a significant increase in cellular cyclic AMP could be detected at concentrations as low as 3 x 10(-10) M and maximal stimulation occurred at 10(-8) M. VIP was approximately 1% as potent as natural secretin and maximal concentrations of secretin plus VIP increased cellular cyclic AMP to the same value as was obtained with a maximal concentration of secretin alone.

Effect of O2, N2, and CO2 composition on nonlinearity of Fleisch pneumotachograph characteristics.

Although the Fleisch pneumotachograph has many advantages, its flow-conductance characteristics are nonlinear and sensitive to changes in gas composition. The purpose of this study was to assess the effect of different O2, N2, and CO2 compositions on the nonlinearity of the Fleisch pneumotachograph flow-conductance characteristics, by use of a recently developed computerized calibration method. Hospital-grade O2 was mixed with room air to obtain seven gas mixtures (containing O2 percentages of 20.9, 28.3, 38.7, 52.8, 66.7, 78.7, and 99.6%). Within the accuracy of the applied method, the measured flow-conductance curves of the pneumotachograph had the same shape. Relative flow resistance of gas mixtures to room air was directly proportional to their O2 composition. Two O2-N2-CO2 mixtures were also tested. Their relative flow resistance compared with room air was proportional to the viscosity ratios. We concluded that the change in O2, N2, and CO2 composition does not affect the nonlinearity of the Fleisch pneumotachograph flow-conductance characteristics. However, the relative flow resistance compared with room air does change in a predictable way.

Computerized determination of pneumotachometer characteristics using a calibrated syringe.

A computerized method has been developed to determine the conductance characteristics of pneumotachometers. Conductance values of the flowmeter, which correspond to all pressure values, can be determined by a weighted averaging technique, when multiple strokes of a precision 3-liter calibrated syringe are used. The conductance values then allow the measured differential pressures to be converted, point by point, into flows. The accuracy of measured volumes is within +/- 0.5% for a 100-stroke calibration process, and calibration with 50 strokes provides +/- 1% accuracy. The method improves the accuracy of the on-line measurements of ventilation. O2 consumption, and CO2 production during exercise.

"Anaerobic threshold": problems of determination and validation.

Despite the popularity of the concept of "anaerobic threshold" (AT), the noninvasive detection criteria remain subjective, and invasive validations of AT have been based on lactate data of arterial, mixed venous, venous, and capillary blood samples without any concern for the possible lactate differences from these sources. Eight normal subjects underwent two exercise tests on a bicycle ergometer. The protocol consisted of 3 min of rest, 3 min of 0 work load, and a 20 W/min ramp (1 W/3 s) until exhaustion. Simultaneous arterial and venous blood samples were drawn during the second test. Noninvasive gas response data were measured using a computerized breath-by-breath stress test system. Threshold phenomenon of the lactate accumulation was not found. The arterial lactate levels increased continuously after the start of the exercise ramp. The rise in venous lactate lagged behind the rise of the arterial lactate by about 1.5 min, and therefore venous lactate was not considered suitable for AT detection. Four independent exercise physiologists determined AT from the gas response data. The reviewer variability (avg range 16%) of AT for a given subject was representative of AT values reported for untrained and trained individuals (40-70% maximum O2 consumption). We concluded that 1) AT is not detectable using invasive methods (arterial and venous lactates); and 2) the noninvasive gas response determination has such a large range of reviewer variability that it is unsuitable for clinical use.

Effects of aminophylline upon the exercise performance of patients with stable chronic airflow obstruction.

To assess the effects of aminophylline upon the exercise performance of patients with chronic airflow obstruction (CAO), we performed ramp exercise tests (1 W/3 s) on six CAO subjects before and after intravenous aminophylline (6 mg X kg-1). The subjects had airflow obstruction (mean FEV1/FVC = 0.53) which did not improve following the inhalation of aerosolized isoetharine. After intravenous aminophylline, maximal oxygen uptake, maximal work rate and exercise duration increased (p less than 0.03) and the subjective dyspnea scores during exercise decreased (p less than 0.05). These changes were not accompanied by increases of FEV1 or peak expiratory flow rate, but maximal inspiratory pressure and peak inspiratory flow rate during exercise increased (p less than 0.05). These observations suggest that aminophylline acutely improves the maximal exercise performance of CAO subjects by mechanisms other than bronchodilation.

Measurement of anaerobic threshold in chronic airflow obstruction.

We compared determinations of anaerobic threshold (AT) made from measurements of arterial lactate concentration with AT determined from ventilatory response measurements of subjects with chronic airflow obstruction (CAO). Six untrained subjects with CAO performed incremental maximal cycle ergometer tests. Ventilation (VE); O2 uptake (VO2), CO2 output (VCO2); end-tidal CO2 fraction (FETCO2); and end-tidal O2 fraction (FETO2) were measured breath by breath. Arterial lactate concentration was sampled at rest and every 30 s during exercise from an indwelling arterial catheter. For three subjects with more severe airflow obstruction, plots of VE/VO2 and FETO2 failed to detect AT. In contrast, a systematic increase of the respiratory gas exchange ratio across the lung (R) accompanied increasing arterial lactate concentrations in all 6 subjects. We conclude that progressive increases of VE/VO2 and FETO2 cannot be relied upon for the measurement of AT in patients with severe CAO. Progressive increases of R unaccompanied by decreasing FETCO2 detect AT in CAO.

Noninvasive evaluation of exercise training in college-age men.

The purpose of this study was to assess noninvasively the effects of intense aerobic training on cardiac structure and function in a group of healthy, college-age men (25 experimental and 11 control, mean age 22 years). Echocardiographic, electrocardiographic (ECG), and fitness measurements were obtained before and after a 3-month endurance training program and compared with similar measurements obtained in nonexercising subjects. The supervised training program consisted of 50-minute jogging sessions 5 days a week at 85% of maximal heart rate. Compared with the control group, echocardiography after training showed an increase in left ventricular (LV) end-diastolic dimension (p less than 0.05). LV posterobasal wall thickness, septal wall thickness and ejection fraction did not change significantly. ECG measurements revealed a decrease in resting heart rate (p less than 0.05) and an increase in R-wave voltage in leads V5 and V6 (p less than 0.01). The measured maximal oxygen consumption increased by 16% (p less than 0.001). These data indicate that intense aerobic training in college-age men results in a significant increase in resting LV end-diastolic dimension and volume. The increase in maximal stroke volume associated with exercise training may be partially explained by these changes in cardiac dimensions.