G. Harley Hartung

Effects of exercise training on left ventricular performance and myocardial perfusion in patients with coronary artery disease

To determine the effects of exercise training on left ventricular performance and myocardial perfusion in coronary artery disease, rest and exercise radionuclide angiocardiography and thallium-201 scintigraphy were performed before and after 12 weeks of training in 16 coronary patients. After training, 15 of the 16 patients had improved exercise tolerance; total treadmill exercise duration increased from (mean +/- standard error of the mean) 491 +/- 37 to 602 +/- 31 seconds (p less than 0.01), and the estimated rate of oxygen consumption (VO2 max) increased from 29.4 +/- 1.4 to 33.8 +/- 1.2 ml/kg per min (p less than 0.001). Resting left ventricular ejection fraction increased from 52 +/- 4 to 57 +/- 4 percent (p less than 0.02); no change occurred in left ventricular functional reserve assessed by ejection fraction and regional wall motion response to exercise at the same rate-pressure product before and after training. Myocardial perfusion at equivalent pre- and post-training cardiac work loads during exercise and on redistribution was unchanged by training. It is concluded that in patients with coronary heart disease, physical training increases exercise tolerance, and results in minimal improvement in resting left ventricular systolic performance. Functional reserve of both left ventricular systolic performance and the coronary circulation appears to be unchanged by exercise training. These data suggest that the beneficial effects of training for 12 weeks in patients with coronary artery disease predominantly result from factors other than improvement in left ventricular pump performance or perfusion.

Effect of alcohol dose on plasma lipoprotein subfractions and lipolytic enzyme activity in active and inactive men

Controversy as to which lipoprotein subfraction of high-density lipoprotein (HDL) increases during alcohol consumption prompted the current study of the effects of two alcohol doses over varying time intervals on plasma lipoproteins and lipolytic enzymes. Measurements were made in 49 healthy men before and after three weeks of abstinence from alcohol and after consumption of one or three 12-ounce cans of beer per day. We found that HDL (10%), HDL2 (14%), and HDL3 (9%) cholesterol, and apolipoprotein A-I (7%) decreased with abstinence from alcohol and then increased with its consumption. These increases were not significant until after 3 weeks of daily alcohol intake, but they were significant in both the one-can and three-cans of beer per day groups. In the 23 inactive subjects HDL and HDL2 cholesterol decreased with abstinence but did not increase significantly with alcohol intake. Lipolytic enzymes were not changed by alcohol manipulation, but the level of lipoprotein lipase was higher and that of hepatic lipase was lower at each measurement point in the 26 habitually active versus the 23 inactive subjects. Adjustment for weight or skinfold thickness did not affect lipoprotein changes over time within groups but did eliminate many of the differences between activity groups. Alcohol consumption seems to be related to possibly beneficial influences on plasma HDL and HDL2 cholesterol, and may thus impact the risk of heart disease.

The relationship of exercise and diet on high-density lipoprotein cholesterol levels in women

The relationship of exercise and diet on high-density lipoprotein (HDL) cholesterol was investigated in 45 long-distance runners (LD), 49 joggers (J), and 47 inactive (I) women. Fasting plasma triglycerides (TG), HDL cholesterol, total cholesterol (TC), and percent body fat (%BF) were measured in women ages 24-58 yr. TG levels were significantly lower in LD compared to I (p less than 0.02). Although TC was not significantly different among groups, HDL-cholesterol was higher in LD (78 mg/dl) compared to J (70 mg/dl) or I (62 mg/dl) (p less than 0.001). Multiple regression analyses indicated that alterations of plasma lipids and lipoprotein levels could not be attributed to intake differences of nutrients. Distance run and %BF were the strongest predictors of HDL-cholesterol in women. LD (23 %BF) were leaner than J (26 %BF) or I (30 %BF); however, when results were adjusted for %BF, significant differences between exercise groups remained for HDL cholesterol.

Effect of exercise training on plasma high-density lipoprotein cholesterol in coronary disease patients.

The effects of chronic exercise training on plasma high-density lipoprotein cholesterol (HDL-C) were studied in 18 male coronary patients. Exercise consisted of aerobic activities utilizing approximately 70% of maximal oxygen uptake (VO2 max) for 20 to 40 minutes, three times weekly for 3 months. Significant increased in VO2 max, HDL-C, HDL-C/total cholesterol, and a decrease in percent body fat were documented after training. No significant changes were found in total cholesterol, triglyceride, body weight, or low-density lipoprotein cholesterol. Vigorous physical training can contribute to increased in HDL-C in patients with coronary disease without changes in total cholesterol or body weight.

Effect of alcohol intake and exercise on plasma high-density lipoprotein cholesterol subfractions and apolipoprotein A-I in women.

Abstinence from alcohol consumption for 3 weeks was followed by 3 weeks of wine intake in 18 inactive and 18 physically active premenopausal women (runners). The runners weighed less and had higher plasma high-density lipoprotein (HDL) cholesterol and lower low-density lipoprotein cholesterol levels than the inactive women. There were no differences between groups in plasma total cholesterol, triglyceride and apolipoprotein A-I concentrations. Runners had higher plasma HDL2 cholesterol concentrations than inactive women (34 +/- 17 vs 19 +/- 12 mg/dl), but HDL3 cholesterol concentration did not differ between the groups (41 +/- 10 vs 39 +/- 9 mg/dl). Addition of 35 g/day of ethanol for 3 weeks did not result in a significant change in either group for any of the variables measured. The amount of exercise appears to be a more important determinant of plasma lipoproteins and apolipoprotein A-I than alcohol intake in premenopausal women.

Accuracy of measured and predicted residual lung volume on body density measurement.

The effects of measured and predicted residual lung volume on the accuracy of body density and percent fat (%Fat) were investigated. Adult fitness subjects (N = 46) had residual lung volume measured with the oxygen dilution method while those from an athlete sample (N = 134) utilized the nitrogen washout technique. Residual lung volume was also predicted with gender-specific regression equations using height and age and from 24% of vital capacity (%FVC). Residual lung volume alpha reliability for the average of four residual lung volume trials exceeded 0.90 (SEM less than = 161 ml) for the oxygen dilution method and 0.99 (SEM = 30 ml) for the average of two nitrogen washout measures. The standard errors for predicted residual lung volume were 579 and 355 ml, respectively, for the men and women in the adult sample and 288 ml for the trained athlete sample. Estimating residual lung volume from %FVC yielded a SEE of 318 ml for the trained athlete sample. Measured residual lung volume errors resulted in errors of 1.04%Fat, 0.87%Fat, and 0.21%Fat for the men, women, and trained athlete samples, respectively. In contrast, predicted residual lung volume measurement errors resulted in errors of 3.70%Fat, 2.85%Fat, and 1.98%Fat for the respective samples and 2.18%Fat when using %FVC with the trained athletes. Measured residual lung volume introduces little %Fat error while predicted residual lung volume introduces a substantial source of measurement error.

Exercise and HDL Cholesterol in Middle-Aged Men

Raising high-density lipoprotein levels with exercise seems to protect against coronary heart disease. Dr. Hartung attempts to show how much exercise is necessary.

Effects of marathon running, jogging, and diet on coronary risk factors in middle-aged men.

Abstract Equal groups (N = 22) of middle-aged marathon runners, joggers, and inactive men were studied to determine the possible effect of their activity levels and life-styles on coronary risk factors. The level of physical activity necessary to minimize coronary risk was studied by evaluating differences among the three groups. Both active groups weighed less, had less triceps skinfold fat, and higher HDL cholesterol levels than the inactive group. Total cholesterol level was not different among the three groups, but the marathoners had significantly lower triglyceride levels than the inactive men. Except for higher V O 2 max and weekly miles run, lower resting heart rate, and percentage fat in the marathoners, no differences were found between the marathon runners and joggers. Dietary data showed that there were not significant differences among the three groups, except that the joggers consumed more dairy products than the inactive group. Marathon runners and joggers both appear to have lower risk factors for coronary disease than inactive men.

A Mimic of the Sick Sinus Syndrome in a Middle-Aged Athlete

Highly trained athletes may have physiological alterations in cardiac pacemaker and conduction function. This article helps clinicians recognize arrhythmias related to exercise conditioning.