Henry S. Miller

Acute exercise: Buffering psychosocial stress responses in women.

We evaluated the experimental hypothesis that an acute bout of aerobic exercise (AE) serves as a buffer to psychosocial stress responses in low to moderate physically fit women. Forty-eight (24 White, 24 Black) 25- to 40-year-old women participated in two counterbalanced experimental conditions: an attention control and a 40-min bout of AE at 70% heart rate (HR) reserve. The attention control and AE treatments were followed by (a) 30 min of quiet rest, (b) exposure to mental and interpersonal threat, and (c) 5 min of recovery. Blood pressure (BP) and HR were monitored at baseline, during the stressors, and throughout recovery. Self-reported distress was assessed before each stressor and upon completion of the recovery period. The results provided clear evidence that exercise dampens BP reactivity to psychosocial stress. Additionally, compared with the attention placebo control, AE reduced both the frequency and intensity of anxiety-related thoughts that occur in anticipation of interpersonal threat and challenge.

The physical activity patterns of cardiac rehabilitation program participants.

PURPOSE This investigation aimed to examine the physical activity patterns of cardiac rehabilitation program (CRP) participants. METHODS The investigation enrolled 53 male and 24 female CRP participants between 46 and 88 years of age. By means of a uniaxial accelerometer (Life-Corder), the amount of physical activity (in kilocalories) and the time spent in physical activity at light (<3 metabolic equivalents [METs]), moderate (3 to 6 METs), and vigorous (>6 METs) intensity were evaluated. In addition to these variables, the MET levels for the CRP and non-CRP periods were calculated. RESULTS The weekly amount of physical activity energy expenditure averaged 1597 +/- 846 kcal/week, and the time spent in light, moderate, and vigorous physical activity averaged, respectively, 375.5 +/- 124.5 minutes, 125.2 +/- 109.4 minutes, and 5.7 +/- 12.8 minutes per week. These levels were significantly lower on non-CRP days than on CRP days: 177 +/- 113 versus 299 +/- 161 kcal/day and, respectively, 49.3 +/- 19.3 versus 59.7 +/- 19.8 minutes, 10.5 +/- 14.6 versus 26.4 +/- 20.4 minutes, and 0.4 +/- 1.7 versus 1.4 +/- 3.0 minutes per day. CONCLUSIONS These results indicate that the amount of physical activity was generally adequate on CRP days, but failed to reach target levels on non-CRP days. Thus CRP participants, when it is medically appropriate, should be encouraged to incorporate lifestyle physical activity, additional exercise, or both on non-CRP days to supplement their caloric expenditure from CRP exercise sessions.

Effects of mode of training on cardiovascular function and body composition of adult men.

The purpose of this investigation was to determine the comparative effects on middle-aged men of training by running, walking, and bicycling. Sedentary men (X age = 38 yrs), who volunteered to participate, were assigned randomly to one of the following training groups: I, running (n = 9); II, walking (n = 9); and III, bicycling (n = 8). All groups trained for 30 min, 3 times/week for 20 weeks at 85 to 90% of maximal heart rate. A control group of seven men of similar qualifications also were evaluated. Training heart rates averaged 90%, 87%, and 87% of maximum for groups I, II, and III, respectively. All experimental groups improved significantly in cardiovascular and body composition measures. The former was shown by significant increases in Vo2max, VEmax, and O2 pulse and a significant decrease in resting heart rate. Body composition results showed that the experimental groups had a significant reduction in body weight, skinfold fat, and abdominal girth measurements. The control group showed no significant changes for any of the variables. It was concluded that improvement in the experimental groups was independent of mode of training.

Comparison of standard- and extended-length participation in cardiac rehabilitation on body composition, functional capacity, and blood lipids

Participation in a standard-length outpatient cardiac rehabilitation program (CRP) for 3 months is known to result in positive changes in body composition, functional capacity, and blood lipids in patients with coronary artery disease. However, there has been little attempt to compare patients who remain active in a formal CRP for an extended length of >1 year with patients who exit after a standard length of 3 months. Consequently, 50 patients underwent a series of tests including a maximal graded exercise treadmill test, assessment of body composition, and fasting blood lipid analysis, at entry to CRP and after a follow-up period that ranged from 1 to 5 years. All patients participated in a standard multidisciplinary cardiac rehabilitation program for 3 months. Twenty-five patients discontinued participation after 3 months and received no other contact from the program staff until follow-up, whereas 25 patients remained active in the program until follow-up. After statistically adjusting for baseline differences between the groups, significant differences were observed between the extended- and standard-length groups at follow-up for body weight (177 vs 183 lbs), percent fat (22% vs 24%), METS (10.5 vs 8.4), high-density lipoprotein level cholesterol (44 vs 39 mg/dl), total cholesterol/high-density lipoprotein ratio (5.2 vs 6.1), and triglycerides (134 vs 204 mg/dl), respectively. No significant differences in the adjusted means were observed between the groups at follow-up for total cholesterol (209 vs 219 mg/dl) and low-density lipoprotein cholesterol (136 vs 138 mg/dl). Data from this study demonstrate the efficacy of extended participation in CRP on body composition, functional capacity, and blood lipids. Greater efforts need to be directed at retaining patients in low-cost, center-based maintenance programs and at extending monitoring of patients exiting standard length CRPs.

Long-term (5-Year) Changes in HDL Cholesterol in Cardiac Rehabilitation Patients Do Sex Differences Exist?

BACKGROUND It is unknown whether the benefits of a cardiac rehabilitation program on HDL cholesterol (HDL-C) are equally achieved in men and women. To study this, we compared changes in HDL-C and other lipids in a large group of men and women participating in a cardiac rehabilitation program for up to 5 years. METHODS AND RESULTS We compared changes in HDL-C and other fasting lipids in 553 men and 166 women participating in a cardiac rehabilitation program at baseline and then annually for up to 5 years. Patients exercised 3 days a week at 70% to 85% of their maximum heart rate predetermined by a symptom-limited treadmill test. Aerobic capacity was estimated in metabolic equivalents (METs), and percent body fat was determined by skin-fold measurements. Baseline HDL-C, LDL cholesterol (LDL-C), and total cholesterol were significantly higher in women, whereas the ratio of total cholesterol to HDL-C was lower. Although both men and women showed an increase in HDL-C after 1 year (10% and 7%, respectively), only the womens level continued to increase over 5 years (20% versus 5% for men, P = .03). The sex difference in change in HDL-C remained after adjustment for age and smoking. A nonsignificant trend toward a greater change in HDL-C in women existed after adjustment for baseline percent body fat and estimated METs. The change in the ratio of total cholesterol to HDL-C was also more favorable in women, with a 38% decrease over 5 years compared with a 14% decrease in men (P = .01). Total cholesterol decreased by 20% in women and 8% in men (P = .001), whereas LDL-C dropped by 34% in women and 15% in men (P = .0001). There was no sex difference in change in triglycerides. CONCLUSIONS Women with heart disease who participate in a cardiac rehabilitation program may achieve greater lipid benefits over longer periods of time than previously demonstrated in men.

Identification of the anaerobic threshold using double product in patients with coronary artery disease.

This study compared the ventilatory threshold with the double-product break point in 104 patients with cardiovascular disease during ramp treadmill testing. The high correlation (r = 0.81) between the double-product break point and the ventilatory threshold, even in patients taking beta blockers, suggests the former method is a viable noninvasive alternative for identifying the anaerobic threshold in patients with cardiovascular disease, particularly when expired gas analysis is not appropriate or available.

The Metabolic Demand of Golf in Patients With Heart Disease and in Healthy Adults

PURPOSE To evaluate the metabolic cost of golf, while pulling a cart, in a group of patients with heart disease (HD) and healthy adults with a wide range of functional capacities. METHODS Twenty male golfers aged 49 to 78 years participated in this study. All participants underwent a graded exercise test (GXT) with expired gas analysis to determine functional capacity. Each patient with HD (n = 10) was matched with a healthy adult of similar age. Each pair completed 9 holes of golf while pulling a cart, during which oxygen consumption was monitored continuously via the Cosmed K4b2 portable unit. RESULTS The average metabolic equivalent (MET) value (1 MET = 3.5 mL x kg(-1) x min(-1)) (mean +/- SEM) for 9 holes of golf in this group of men with HD (4.1 +/- 0.1 METs) was similar to that previously reported value of 4.3 METs. Whereas the average MET responses were similar between the groups, when expressed relative to peak oxygen consumption, on average, patients with HD worked at a significantly higher percentage of their functional capacity (57 +/- 2.7%) compared to the healthy adults (46 +/- 2.6%). Some patients with HD exceeded 100% of GXT MET level during golf. In contrast, some healthy adults failed to reach 60% of GXT MET level during golf. CONCLUSIONS Based on these data, walking the golf course while pulling a cart appears to provide an adequate training stimulus for most patients with HD. However, some lower fit patients with HD (< 8 METs) are in danger of exceeding a safe level and should be encouraged to monitor intensity on the golf course and consider using a motorized cart. For most individuals who are more fit (functional capacity > or = 8 METs), golf does not appear to provide the stimulus generally associated with improvement in functional capacity.

Effects of Cardioselective Beta Blockers on Ventilation and Gas Exchange in Patients With Heart Disease During Ramp Treadmill Testing

The effects of cardioselective beta blockade on ventilation and gas exchange were investigated in 12 male subjects with coronary artery disease during ramp treadmill testing. Patients were able to maintain much of their functional capacity as measured by oxygen consumption in the beta-blocked condition, and also maintained minute ventilation by increasing respiratory rate despite a decrease in tidal volume.

The prediction of oxygen consumption during arm work ergometry

Abstract The purpose of this study was to examine oxygen consumption (VO2) patterns during arm work ergometry and to determine if VO2 (ml kg‐1 min‐1) could be accurately predicted from workload and attribute variables. Thirty‐two male subjects were chosen to form a homogeneous group in regard to age, gender, and percentage body fat, but at the same time to produce a large range in body weight. Each subject performed a continuous exercise test on an arm ergometer to voluntary exhaustion. Oxygen consumption and heart rate were determined and averaged for each workload. Multiple linear regression with a forward solution was utilized in the primary analysis of the data; dependent variable, VO2 (ml kg‐1 min‐1). VO2 (1 min‐1) and VO2 (ml kg‐1 min‐1) increased throughout the workload range, being significantly greater for light than heavy subjects, particularly at high workloads. Workload, weight and the workload × weight product (workload × weight/100) added significantly to the prediction of VO2 (ml kg‐1 min‐1...

A profile of a champion distance runner: age 60.

ABSTRACTA world champion runner, age 60, was evaluated in various performance and cardiopulmonary variables, body composition, and serum lipid measures. The subject had world record performances in the 60− to 69-year-old age bracket in the following events: one-mile run, 5:19; 5,000 meters, 17:47; a