Low Intake of Choline Is Associated with Diminished Strength and Lean Mass Gains in Older Adults.

OBJECTIVES: Choline is an essential micronutrient for many physiological processes related to exercise training including biosynthesis of acetylcholine. Though dietary choline intake has been studied in relation to endurance training and performance, none have studied it during resistance exercise training (RET) in older adults. The objective of the study was to examine the relationship between choline intake and muscle responses to RET in older adults. METHODS: Forty-six, 60-69-year-old individuals (M=19, F=27) underwent 12 weeks of RET (3x/week, 3 sets, 8-12 reps, 75% of maximum strength [1RM], 8 exercises). Body composition (DEXA) and 1RM tests were performed before and after training. After analyzing 1,656 diet logs (3x/week, 46 participants, 12 weeks), participants' mean choline intakes were categorized into three groups: Low (2.9-5.5 mg/kg lean/d), Med-Low (5.6-8.0 mg/kg lean/d), or Adequate (8.1-10.6 mg/kg lean/d). These correspond to <50%, ~63%, and ~85% of Adequate Intake (AI) for choline, respectively. RESULTS: Gains in composite strength (leg press + chest press 1RM) were significantly lower in the Low group compared with the other groups (Low: 30.9 ± 15.1%, Med-Low: 70.3 ± 48.5%, Adequate: 81.9 ± 68.4%; p=0.004). ANCOVA with cholesterol, protein, or other nutrients did not alter this result. Reduced gains in lean mass were also observed in the Low group, compared with higher choline intake of 5.6-10.6 mg/kg lean/d (1.3 ± 0.6% vs. 3.2 ± 0.6%, p<0.05). CONCLUSION: These data suggest that this population of older adults does not consume adequate choline and lower choline intake is negatively and independently associated with muscle responses to RET.

Combination of estrogen replacement and exercise protects against HDL oxidation in post-menopausal women.

The incidence of atherosclerosis and cardiovascular disease (CVD) in women increases following menopause and has been associated with a reduction in circulating estrogen. Increased CVD risk is also perpetuated by sedentary lifestyle. Growing evidence indicates that oxidation of lipoproteins leads to a powerful immune response, disruption of normal lipoprotein function, and deposition of atherosclerotic plaques. For example, once high-density lipoproteins (HDL) are oxidized, they lose the ability to a) participate in reverse transport of cholesterol to the liver, and b) protect low-density lipoproteins (LDL) against oxidation. The purpose of this study was to determine the effects of combining estrogen replacement and exercise upon lipid peroxidation of the HDL fraction (HDL-ox). Blood samples were drawn from 34 post-menopausal women from four groups: women who were not receiving estrogen replacement and who were sedentary (NSD) (n = 9); women who were not receiving estrogen replacement and who were participating in regular exercise (NEX) (n = 8); women who were receiving estrogen replacement and who were sedentary (ESD) (n = 8); and women who were receiving estrogen replacement and who were participating in regular exercise (EEX) (n = 9). Total-HDL cholesterol was significantly higher (p<0.05) in EEX when compared with NEX, NSD, and ESD. HDL-ox was assessed via malondialdehyde (MDA). Mean (+/- SEM) values for HDL MDA expressed in nM are as follows: NSD = 903.3 +/- 118.4; NEX = 1226.7 +/- 247.7; ESD = 876.7 +/- 116.3; EEX = 537.4 +/- 74.8. EEX lipid peroxidation was significantly (p = 0.02) lower than NEX. Lipid peroxidation tended to be lower in EEX than in NSD and ESD (p = 0.07). These data indicate that the combination of estrogen replacement and regular exercise in post-menopausal women may be most effective in reducing oxidation of HDL in vivo.

The acute versus the chronic response to exercise.

PURPOSE: There is strong and consistent evidence that a single exercise session can acutely reduce triglycerides and increase high-density lipoprotein (HDL) cholesterol (HDL-C), reduce blood pressure, and improve insulin sensitivity and glucose homeostasis. Such observations suggest that at least some of the effects on atherosclerotic cardiovascular disease (ASCVD) risk factors attributed to exercise training may be the result of recent exercise. RESULTS: These acute and chronic exercise effects cannot be considered in isolation. Exercise training increases the capacity for exercise, thereby permitting more vigorous and/or more prolonged individual exercise sessions and a more significant acute effect. The intensity, duration, and energy expenditure required to produce these acute exercise effects are not clearly defined. The acute effect of exercise on triglycerides and HDL-C appears to increase with overall energy expenditure possibly because the effect maybe mediated by reductions in intramuscular triglycerides. Prolonged exercise appears necessary for an acute effect of exercise on low-density lipoprotein (LDL) cholesterol (LDL-C) levels. The acute effect of exercise on blood pressure is a low threshold phenomenon and has been observed after energy expenditures requiring only 40% maximal capacity. The acute effect of exercise on glucose metabolism appears to require exercise near 70% maximal, but this issue has not been carefully examined. CONCLUSIONS: Exercise has definite acute effects on blood lipids, blood pressure, and glucose homeostasis. Exercise also has acute effects on other factors related to atherosclerosis such as immunological function, vascular reactivity, and hemostasis. Considerable additional research is required to define the threshold of exercise required to produce these putatively beneficial effects.

Influence of cholesterol status on blood lipid and lipoprotein enzyme responses to aerobic exercise.

To compare postexercise changes in plasma lipids and lipoprotein enzymes in 13 hypercholesterolemic (HC) and 12 normocholesterolemic men [total cholesterol (TC) 252 +/- 5 vs. 179 +/- 5 mg/dl], fasting blood samples were obtained 24 h before, immediately, 24, and 48 h after a single bout of treadmill walking (70% peak O(2) consumption, 500 kcal expenditure). Significant findings (P < 0.05 for all) for plasma volume-adjusted lipid and enzyme variables were that TC, low-density-lipoprotein cholesterol, and cholesterol ester transfer protein activity were higher in the HC group but did not influence the lipid responses to exercise. Across groups, TC was transiently reduced immediately after exercise but returned to baseline levels by 24 h postexercise. Decreases in triglyceride and increases in high-density-lipoprotein cholesterol (HDL-C) and HDL(3)-C were observed 24 h after exercise and lasted through 48 h. Lipoprotein lipase activity was elevated by 24 h and remained elevated 48 h after exercise. HDL(2)-C, cholesterol ester transfer protein activity, hepatic triglyceride lipase, and lecithin: cholesterol acyltransferase activities did not change after exercise. These data indicate that the exercise-induced changes in HDL-C and triglyceride are similar in HC and normocholesterolemic men and may be mediated, at least in part, by an increase in lipoprotein lipase activity.

Diet and short term plasma lipoprotein-lipid changes after exercise in trained Men.

To test the effect of diet on the short-term lipid response to exercise, fourteen moderately trained (VO2max: 50.2 +/- 6.7 ml/kg/min), healthy men (mean age: 28 +/- 4 years) were alternately fed a high fat (60 +/- 6.7% fat) and a high carbohydrate (63 +/- 3.2% carbohydrate) isoenergetic diet for 2 weeks in a randomized crossover design. During the last 4 days of the treatments, fasting total cholesterol, triglyceride, HDL-cholesterol, and HDL3-cholesterol were measured the day before, and again immediately, 24 hr, and 48 hr after exercise (4190 kJ, 70% VO2max). LDL-cholesterol and HDL2-cholesterol were calculated. Lipid concentrations were adjusted for plasma volume changes after exercise. A 2 (diet) x 4 (time) ANOVA with repeated measures revealed no significant interaction between the diet and exercise treatments. Furthermore, diet alone did not influence lipid concentrations in these trained men. Exercise resulted in an increase in HDL-C (10.7%) and HDL3-C (8.5%) concentrations and a concomitant fall in triglyceride (-25%) and total cholesterol (-3.5%). Thus, we conclude that diet composition does not affect the short-term changes in blood lipids and lipoproteins that accompany a single session of aerobic exercise in moderately trained men.

The effects of menopausal status and exercise training on serum lipids and the activities of intravascular enzymes related to lipid transport.

The study purpose was to compare the effect of exercise training on serum lipid and apolipoprotein concentrations and the activities of intravascular enzymes related to lipid transport in previously untrained eumenorrheic, premenopausal (PRM) women (n = 21; mean age, 36 +/- 3 years) and estrogen-free postmenopausal (POM) women (n = 16; mean age, 68 +/- 8 years). Subjects trained at a progressive intensity and duration (50% to 75% maximal O2 consumption [VO2max], 200 to 300 kcal/session) 4 d/wk for 12 weeks. Before and after training, VO2max, body weight, relative body fat, and fasting blood samples were obtained following 2 weeks on a standardized diet designed to maintain body weight and during the early follicular stage for the PRM group. Blood samples were analyzed for serum total cholesterol (TC), triglyceride (TG), high-density lipoprotein cholesterol (HDL-C), the cholesterol content of the HDL3 subfraction, apolipoprotein (apo)A-I and apoB, lipoprotein(a), and the activity of lecithin:cholesterol acyltransferase (LCAT). Total and hepatic triglyceride lipase activity (HTGLA) were determined from plasma samples obtained after heparin administration. The cholesterol content of the low-density lipoprotein (LDL) and HDL2 subfractions and endothelial-bound lipoprotein lipase activity (LPLA) were calculated. A two (group) x two (time) multivariate ANOVA (MANOVA), with repeated measures for time indicated that the exercise-induced changes in physiological measurements, serum lipid or apolipoprotein concentrations, or enzyme activities did not differ between groups. Serum concentrations of TC, LDL-C, and HDL3 cholesterol, TG, and apo A-I and apoB were higher in POM women compared with the PRM group (P < .05 for all). For the combined groups, body weight and relative body fat did not change with training, but VO2max increased an average of 18.5% (P < .05). LPLA, HTGLA, and LCAT activity were unaltered with exercise training. Except for a small but significant decrease in HDL-C (-5.5%) and an elevation in apoB (4.3%; P < .05 for both), the concentrations of serum lipids and apolipoproteins did not change over the training period. We conclude that in previously untrained women, menopausal status does not influence the exercise training response of serum lipids or apolipoproteins or activities of intravascular enzymes related to lipid transport.

Peak exercise hemodynamics in exercising postmenopausal women taking versus not taking supplemental estrogen.

The purpose of this study was to determine whether supplemental estrogen influences cardiovascular hemodynamics at peak exercise in endurance trained and sedentary postmenopausal women. Subjects were 22 women between 3 and 10 yr past menopause who had engaged in endurance exercise at least three times per week for one or more years. Twelve of the women had taken estrogen replacement for at least 1 yr (ER) while the other 10 had never taken supplemental estrogen (NOER). Peak cardiac output (Qpeak) and, subsequently, peak cardiac index (QIpeak) were calculated by regressing submaximal cardiac output values on corresponding oxygen consumptions and extrapolating to peak exercise. Peak oxygen consumption in the two groups were almost identical; however, the ER group demonstrated a higher QIpeak in conjunction with a lower arteriovenous oxygen difference and a lower peripheral resistance. It was concluded that estrogen supplementation may be associated with higher peak cardiac outputs in exercise trained postmenopausal women via alterations in the peripheral vascular and oxygen kinetic responses to maximal exercise.

Training intensity, blood lipids, and apolipoproteins in men with high cholesterol.

Twenty-six hypercholesterolemic men (mean cholesterol, 258 mg/dl; age, 47 yr; weight, 81.9 kg) completed 24 wk of cycle ergometer training (3 days/wk, 350 kcal/session) at either high (n = 12) or moderate (n = 14) intensity (80 and 50% maximal O2 uptake, respectively, randomly assigned) to test the influence of training intensity on blood lipid and apolipoprotein (apo) concentrations. All physiological, lipid, and apo measurements were completed at 0, 8, 16, and 24 wk. Lipid data were analyzed via two x four repeated-measures analysis of variance (alpha = 0.0031). Training produced a significant decrease in body weight and increase in maximal O2 uptake. No interactions between intensity and weeks of training were noted for any lipid or apo variable, and no between-group differences were significant before or throughout training. Therefore, intensity did not affect the training response. Regardless of intensity, apo AI and apo B fell 9 and 13%, respectively, by week 16 and remained lower through week 24 (P < 0.0003). Total cholesterol fell transiently (-5.5%) by week 16 (P < 0.0021) but returned to initial levels by week 24. Triglyceride, low-density-lipoprotein cholesterol, and high-density-lipoprotein (HDL) cholesterol did not change with training. In contrast, HDL2 cholesterol rose 79% above initial levels by week 8 and 82% above initial levels by week 24 (P < 0.0018); HDL3 cholesterol fell 8 and 13% over the same training intervals (P < 0.0026). These data show that changes in blood lipid and apo concentrations that accompany training in hypercholesterolemic men are not influenced by exercise intensity when caloric expenditure is held constant.

Effects of training and a single session of exercise on lipids and apolipoproteins in hypercholesterolemic men.

To differentiate between transient (acute) and training (chronic) effects of exercise at two different intensities on blood lipids and apolipoproteins (apo), 26 hypercholesterolemic men (cholesterol = 258 mg/dl, age = 47 yr, weight = 81.9 kg) trained three times per week for 24 wk, 350 kcal/session at high (80% maximal O2 uptake, n = 12) or moderate (50% maximal O2 uptake, n = 14) intensity. Serum lipid and apolipoprotein (apo) concentrations (plasma volume adjusted) were measured before and immediately, 24, and 48 h after exercise on four different occasions corresponding to 0, 8, 16, and 24 wk of training. Data were analyzed using three-way repeated-measures multivariate analysis of variance followed by analysis of variance and Duncan's procedures (alpha = 0.05). A transient 6% rise in low-density-lipoprotein cholesterol measured before training at the 24-h time point was no longer evident after training. Triglycerides fell and total cholesterol, high-density-lipoprotein cholesterol (HDL-C), HDL3-C, apo A-I, and apo B rose 24-48 h after exercise regardless of training or intensity. Total cholesterol, HDL3-C, apo A-I, and apo B were lower and HDL2-C was higher after training than before training. Thus exercise training and a single session of exercise exert distinct and interactive effects on lipids and apolipoproteins. These results support the practice of training at least every other day to obtain optimal exercise benefits.

Characterization and quantitation of the apoproteins of high-density lipoprotein by capillary electrophoresis.

A method has been developed using capillary electrophoresis (CE) to quantitate plasma levels of apoprotein A-I (apoA-I) and apoprotein A-II (apoA-II) in high-density lipoprotein (HDL) samples. ApoA-I and apoA-II are resolved by CE in delipidated and non-delipidated HDL samples. Concentrations of apoA-I and apoA-II were calculated from their peak areas in the electropherogram. Results of the analysis of Sigma plasma standards (Controls 1 and 2) using CE are in good agreement with values obtained by Sigma using immunoturbidimetric assay. CE and reverse-phase high-performance liquid chromatography (RP-HPLC) were found to be complementary in the study of apoA-I and apoA-II. RP-HPLC resolves the isoforms of purified apoA-I and apoA-II, but it cannot resolve mixtures of them because the retention times of the isoforms overlap. CE separates apoA-I from apoA-II, but it does not resolve the isoforms. Matrix-assisted laser desorption/ ionization mass spectrometry was used to identify the isoforms of apoA-I and apoA-II by their molecular weight (M(r)) in fractions collected from RP-HPLC.

Lipid and lipoprotein changes in women following 6 months of exercise training in a worksite fitness program.

It was the purpose of this investigation to examine the influence of a worksite aerobic training program on serum lipid and lipoproteins and cardiovascular fitness in female employees. Thirty-seven healthy but previously untrained, female employees (Ss) from Westinghouse Corporation, (College Station, Texas) volunteered for the study. Ss were randomly assigned to either an exercise group (Ex) (n = 20) or control group (C) (n = 17). Prior to training (PRE) and following training (POST), all Ss were measured for weight (WT), body composition (%FAT) and tested for maximal oxygen consumption (VO2 max). PRE and POST Lipid analysis included: total cholesterol (TC), high-density lipoprotein cholesterol (HDL-C), low-density lipoprotein cholesterol (LDL-C), very low-density lipoprotein cholesterol (VLDL-C), and triglycerides (TG). Following PRE testing, the Ex group aerobically trained by walking, jogging and/or cycling, at least 3 days per wk for 24 wks. Exercise training resulted in an improvement in VO2 max (p < 0.0006) and a 2 kg WT loss in Ex (p < 0.025) with no change in C. Both Ex and C Ss exhibited a loss in %-FAT (p < 0.0001), and a decrease in TC (p < 0.0001) and LDL-C (p < 0.0001). No differences were observed between groups or over the training period for VLDL-C or TG. Although HDL-C increased 6 mg/dl in the Ex group but not in C, this difference did not reach statistical significance (p < 0.0625). These results demonstrate that aerobic training by females in a worksite fitness program significantly improves cardiovascular fitness without altering lipids or lipoproteins.

Changes in serum lipids and apolipoproteins after exercise in men with high cholesterol: influence of intensity.

The purpose of this study was to characterize the short-term changes in blood lipid and apolipoprotein concentrations in healthy hypercholesterolemic men after high-intensity [80% maximal O2 uptake (VO2max); n = 20] or moderate-intensity (50% VO2max; n = 19) cycle ergometer exercise balanced for caloric expenditure (350 kcal). The men's age, height, weight, %fat, and VO2max were 46 +/- 2 yr, 173 +/- 7 cm, 82.7 +/- 2.2 kg, 28 +/- 1%, and 31.1 +/- 1.0 ml O2.kg-1.min-1, respectively. Blood samples were drawn before exercise, immediately after exercise, then 24 and 48 h later, and concentrations of all variables were adjusted for changes in plasma volume. Significant changes (P < 0.0016) were as follows: total and low-density lipoprotein cholesterol fell by 4% immediately after exercise and then rose by 5-8% by 48 h. Triglycerides were 18 and 15% lower at 24 and 48 h, respectively. HDL-cholesterol, high-density lipoprotein3-cholesterol, and apolipoprotein B rose 8-9% by 24 h and remained elevated. High-density lipoprotein2-cholesterol rose by 27% by 48 h after exercise, but this change was not significant. Apolipoprotein A-I did not change with exercise. The response patterns were not affected by exercise intensity. These data show that a single session of exercise performed by untrained hypercholesterolemic men alters blood lipid and apolipoprotein concentrations. Furthermore, the postexercise response patterns are not influenced by exercise intensity, as long as caloric expenditure is held constant.

The effects of endurance training on functional capacity in the elderly: a meta-analysis.

In this investigation, meta-analysis was used to delineate exercise induced changes in the VO2max of older individuals and test a null hypothesis of no significant training effects. Parameters included in the analysis were age of the subjects, length of the training regimen, frequency and duration of exercise bouts, pretraining VO2max, posttraining VO2max, and the difference between pretraining and posttraining VO2max (delta VO2max). Effect size for training-induced improvements in VO2max was calculated, corrected for bias, weighted, and analyzed according to contemporary meta-analysis procedures. The mean effect size was found to be 0.65 standard deviation units, representing an improvement in oxygen consumption of 22.8%. The mean effect size was also significantly different from 0 (P < 0.0001), and the null hypothesis was rejected. Stepwise regression analysis indicated that length of training, pretraining VO2max, and duration of training bouts accounted for 59% of the total variation in delta VO2max. In addition, age was found to be inversely correlated with pretraining VO2max (r = -0.56, P = 0.002), and delta VO2max (r = -0.56, P = 0.003). It was concluded that endurance training significantly increases functional capacity in the elderly, and that the increase is related to subject age, duration of exercise bouts, length of the training regimen, and pretraining VO2max.

Acute effects of walking on serum lipids and lipoproteins in women.

The purpose of this study was to characterize and evaluate the acute effects of walking performed of fairly light (50% VO2max) and moderate (70% VO2max) intensities on serum lipids and lipoproteins in a group of premenopausal (n = 11) and a group of postmenopausal (n = 10) women. Premenopausal women were (x +/- SEM) 34.5 +/- 1.1 years of age, had 22.8 +/- 1.7% body fat and a 2.47 +/- 0.08 l.min-1 VO2max. Postmenopausal women were 54.8 +/- 2.5 years of age, had 37.9 +/- 0.9% body fat and a 2.06 +/- 0.15 l.min-1 VO2max. All subjects walked on a motor-driven treadmill at each respective intensity of exercise for a total duration sufficient to expend 350 kcal of energy. Dependent variables included total cholesterol (TC), high-density lipoprotein cholesterol (HDL-C) and its subfractions HDL2-C and HDL3-C, low-density lipoprotein cholesterol (LDL-C), and triglycerides (TG). Blood samples were obtained at baseline (pre-exercise), immediately post-exercise (IPE), and at 24 hours and 48 hours post-exercise. A repeated measures design was employed controlling for diet, menstrual cycle periodicity, natural menopause, and plasma volume shifts. A 2 x 4 ANOVA was used to test for differences among means for each group separately. Significant (p < 0.05) time exercise intensity interactions were found for TC and LDL-C for the premenopausal women. This non-parallel change across exercise intensity condition created significant differences at IPE for both TC and LDL-C. Furthermore, an IPE increase in TG (p < 0.05) was observed.(ABSTRACT TRUNCATED AT 250 WORDS)

Maximal exercise and acute mood response in women.

The present study was designed to characterize and assess the reliability of acute mood responses to maximal exercise in women. All subjects (N = 22; age = 45 +/- 2.5 yr; BMI = 24.3 +/- 0.9 kg/m2) participated in two maximal walking tests spaced approximately one month apart. The abbreviated Profile of Mood States (POMS) questionnaire was administered immediately prior to and within 5 min following maximal exercise at both occasions. Maximal heart rate, rating of perceived exertion, and functional aerobic capacity responses indicated compliance to maximal exertion at both tests. Using repeated measures ANOVA, no significant (p < .05) differences were noted between the two tests for any of the POMS subscales. Significant pre to postexercise increases were noted for fatigue and self-esteem subscales while the tension and vigor affects significantly decreased. Because no interactions were found, these effects are concluded to be independent of the order in which the tests were performed. Additionally, intraclass correlations computed for each respective POMS subscale, ranged between 0.69 and 0.81 for fatigue, tension, vigor, self-esteem, confusion, and total mood disturbance. The anger and depression subscales were noted to have intraclass correlations of 0.29 and 0.43, respectively, and may have been influenced by a floor effect in this study population. It is concluded that the abbreviated POMS questionnaire may be reliably used to assess acute mood responses to maximal exercise in women and that even maximal exertion has the potential to acutely benefit mood by decreasing tension and increasing self-esteem.

Endurance training, cardiovascular function and the aged.

Independent of disease, age-associated changes in cardiovascular function include anatomical, physiological, and haemodynamic alterations that are generally without pathological consequence. Decrements in adrenergic receptor response, arterial distensibility, ventricular compliance, and contractile performance seem to be compensated for by enhanced atrial contribution to ventricular filling, prolongation of systole, and increased reliance on the length-tension relationship of cardiac muscle. Summarily, these compensations constitute increased utilisation of the Frank-Starling mechanism. Endurance training beneficially alters aging cardiovascular function both at rest and during exercise. An increase in end diastolic volume and ejection fraction demonstrate an enhancement of the length-tension relationship of myocardial tissue in maintaining resting and exercise cardiac outputs. The decline in maximal cardiovascular function is not preventable. It was also concluded that endurance exercise improves clinical and psychosocial factors that enhance the quality of life for elderly individuals. Future research efforts should attempt to determine if and by what mechanisms endurance training may contribute to the regression of atherosclerotic lesions and the development of collateral vessels in senescent myocardium.

Cardiac structure and function in women basketball athletes: seasonal variation and comparisons with nonathletic controls.

To characterize hypertrophy and quantify seasonal changes in cardiac structure and function of women collegiate basketball (BB) athletes (n = 15), echocardiographic (echo) measurements were made in the fall (FALL1), winter (WIN), and spring (SPR), then again during the subsequent fall (FALL2; n = 10). Comparisons were made to age-matched nonathletes (NA) measured during FALL1 (n = 22) and SPR (n = 5). Left ventricular (LV) internal dimension-diastole (LVIDd), LV end-diastolic volume (LVEDV), stroke volume (SV), LV mass (LVM), septal thickness (IVS), LV posterior wall thickness (LVPW), right ventricular (RV) internal dimension-diastole (RVIDd), and aortic root diameter (AOD) were significantly larger (12-70%) in the athletes; RVIDd-, LVEDV-, SV-, and LVM-index were also significantly greater (8-46%). From FALL1 to SPR measurement periods, LVIDd, RVIDd, LVEDV, SV, IVS, and LVM-index increased significantly (7-18%) in the athletes. Over the same period of time, LVIDd, LAD, AOD, LVEDV, and SV measured in the five NA subjects increased significantly. In the athletes, LVIDs, RVIDd, IVS, LVPW, and LVM decreased significantly (5-30%) from the SPR to FALL2 measurement period. These data characterize the general nature of the cardiac hypertrophy noted in women BB athletes compared to NA controls and show that distinct changes in heart structure corresponding to different periods of the competitive season can occur in these athletes.

Mandatory exercise and heart disease risk in fire fighters. A longitudinal study.

After undergoing initial assessments of percentage of body fat (% fat), triglycerides (TG), total cholesterol (TC), high-density lipoprotein cholesterol (HDL-C), low-density lipoprotein cholesterol (LDL-C), and maximal oxygen consumption (VO2Max), a group of 24 paid male fire fighters (mean age, 30.1 +/- 7.7 years) began a mandatory exercise program. The physiological variables mentioned above were assessed once a year for the subsequent 5 years. A repeated-measures multivariate analysis of variance followed by univariate post hoc techniques showed a minimal but statistically significant improvement in % fat (-1.43% +/- 0.66%) and TG (-27.54 +/- 10.44 mg/dl) over the 5-year period. Significant differences in TC, HDL-C, LDL-C, and VO2Max were noted over the years, but their magnitudes were small and no pattern was demonstrated. Each of the 5-year means for TC, LDL-C, % fat, and VO2Max were outside the desirable ranges. We concluded that mandatory exercise programs do not significantly alter the risk factor status or the aerobic fitness levels of fire fighters and that a significant number of the latter demonstrate a higher than average risk for cardiovascular disease.

Oxygen consumption and cardiac response of short-leg and long-leg prosthetic ambulation in a patient with bilateral above-knee amputation: comparisons with able-bodied men.

This study measured oxygen uptake (VO2), minute ventilation (VE), and heart rate (HR) in a bilateral above-knee (AK) amputee and in three able-bodied controls during progressive treadmill exercise. Walking conditions for the amputee included using bilateral short-leg (SL) and long-leg (LL) prostheses. A progressive treadmill protocol to maximal capacity was used for the amputee and duplicated by the control subjects. An automated system was used to measure VO2, VE, and HR throughout exercise. Data analysis was restricted to the use of parameter averages and percentages to describe differences between experimental conditions. Maximal VO2 for the amputee averaged 23.3mL/kg-1/min-1 with the LL and 22.8mL/kg-1/min-1 with the SL prostheses, a negligible difference between conditions; however, exercise duration was 27% longer when using the SL prostheses. In addition, when averaged over the first four stages of exercise, VO2, VE, and HR were 24%, 32%, and 14% higher, respectively, when the LL prostheses were used. Treadmill walking by unimpaired controls averaged 47% and 79% more economical than walking with the SL or LL prostheses, respectively. These results demonstrate that the use of currently available AK prostheses requires significant energy expenditure, which limits their use to only the most physically fit individuals.

Exercise modality and selected coronary risk factors: a multivariate approach.

To evaluate group differences in coronary risk which could be attributed to the modality of habitual exercise, selected physiologic and lipid indices of coronary artery disease (CAD) were measured in 57 endurance trained (ET), strength trained (ST), or sedentary (SED) men (19 per group, aged 21 to 44 yr). Initial data reduction accomplished with principle component analysis identified three factors with eigenvalues greater than one. Orthogonal rotation of the preliminary solution demonstrated that low density lipoprotein cholesterol (LDL-C), percent body fat (%BF) and VO2max, and high density lipoprotein cholesterol (HDL-C) could be used to represent Factors 1, 2, and 3, respectively. The subsequent MANOVA using these variables proved significant. Post hoc analysis via simultaneous confidence intervals indicated that LDL-C group differences were not significant. Values for %BF and HCL-C in the ST group (14.0% and 1.17 mmol.l-1, respectively) were between but did not differ significantly from respective values in the ET (11.8% and 1.34 mmol.l-1) and SED (18.7% and 1.13 mmol.l-1) groups. However, %BF and HDL-C differences between the ET and SED groups were significant. The VO2max of the ET subjects (63.2 ml.kg-1.min-1) was significantly higher than that of either the ST or SED subjects (49.5 and 46.7 ml.kg-1.min-1, respectively). These results suggest that ET is the most effective modality of exercise for CAD risk reduction while benefits derived from ST are minimal.