Long-term effects of exercise on psychological functioning in older men and women

The purpose of this study was to determine the psychological, behavioral, and cognitive changes associated with up to 14 months of aerobic exercise training. For the first 4 months of the study, 101 older (greater than 60 years) men and women were randomly assigned to one of three conditions: Aerobic exercise, Yoga, or a Waiting List control group. Before and following the intervention, all subjects completed a comprehensive assessment battery, including measures of mood and cognitive functioning. A semi-crossover design was employed such that, following completion of the second assessment, all subjects completed 4 months of aerobic exercise and underwent a third assessment. Subjects were given the option of participating in 6 additional months of supervised aerobic exercise (14 months total), and all subjects, regardless of their exercise status, completed a fourth assessment. Results indicated that subjects experienced a 10-15% improvement in aerobic capacity. In general, there were relatively few improvements in cognitive performance associated with aerobic exercise, although subjects who maintained their exercise participation for 14 months experienced improvements in some psychiatric symptoms. However, the healthy subjects in this study were functioning at a relatively high level to begin with, and exercise training may produce greater improvements among elderly with concomitant physical or emotional impairments.

Aerobic exercise reduces levels of cardiovascular and sympathoadrenal responses to mental stress in subjects without prior evidence of myocardial ischemia

Thirty-seven healthy type A men (mean age 42 years) were randomly assigned to either an aerobic exercise training group or to a strength and flexibility training group. Before exercise, subjects underwent comprehensive physiologic and behavioral assessments, including graded exercise treadmill testing with direct measurement of oxygen consumption (VO2) and measurement of cardiovascular (heart rate, systolic and diastolic blood pressure and rate pressure product) and neuroendocrine (epinephrine and norepinephrine) responses to mental arithmetic. The aerobic exercise consisted of walking and jogging at an intensity of greater than or equal to 70% maximal heart rate reserve for 1 hour 3 times/week for 12 consecutive weeks. The strength training consisted of 1 hour of circuit Nautilus training 2 times/week for 12 weeks. At the completion of the exercise program, all subjects underwent repeat testing. For the aerobic group, peak VO2 increased significantly from 33.6 to 38.4 ml/kg/min (p less than 0.001), whereas the strength group only achieved a slight increase from 34.5 to 35.6 ml/kg/min (difference not significant). During the mental arithmetic, the aerobic group experienced a greater reduction in levels of heart rate, diastolic blood pressure and rate pressure product than the strength group (after completing the exercise training programs). The aerobic group also tended to secrete less epinephrine and to show a faster recovery than the strength group after the exercise program. In addition, the aerobic group tended to exhibit less cardiovascular reactivity to mental stress after exercise training. These data suggest that aerobic exercise reduces levels of cardiovascular and sympathoadrenal responses during and after mental stress.

Cardiovascular responses during upright and semi-recumbent cycle ergometry testing

To compare cardiovascular (CV) responses during cycle ergometry testing, 20 unmedicated mild hypertensive subjects (10 male, 10 female; mean age = 47.9 yr) underwent exercise testing on an upright (UP) cycle and a semi-recumbent (SR) cycle. Tests were administered in counterbalanced order on two separate days. Heart rate (HR), blood pressure (BP), ventilation (VE), and rate pressure product (RPP) were recorded at absolute workloads (1.0 and 1.5 l.min-1) as well as at relative workloads (50, 75, and 90% of VO2 peak). In addition, the CV variables were measured at rest and peak exercise for each position. At absolute submaximal levels, women had higher HR, VE, and RPP values in both positions, reflecting responses at a greater percentage of their maximum exercise capacity. At relative workloads, HRs were significantly lower at rest and at 75 and 90% VO2 peak in the SR position. Men had greater systolic blood pressure (SBP) and RPP in both positions, and RPP was significantly lower at rest and at 75 and 90% VO2 peak in the SR position. Women displayed lower VE at all relative workloads. At peak exercise, subjects achieved significantly higher peak heart rates on the upright cycle (UP = 163 bpm, SR = 157 bpm). The UP cycle was associated with higher levels of peak VO2. The ability to achieve a higher HR and greater VO2 at peak exercise suggests that the UP cycle ergometer may be a preferable mode to the SR ergometer for evaluating maximal exercise performance among patients with mild hypertension.

Comparison of high- and low-intensity exercise training early after acute myocardial infarction

The effects of the intensity of exercise training on cardiorespiratory variables were investigated in a consecutive series of men with recent (median 8 weeks) acute myocardial infarction. Forty-five patients were randomly assigned either to a high- (65 to 75% maximum oxygen consumption rate [VO2max]) or to a low-intensity (less than 45% VO2max) exercise group. Patients engaged in medically supervised aerobic training 3 sessions a week for 12 weeks. With training, mean VO2max significantly increased by 11% (2.09 to 2.31 liters/min) within the high group and by 14% (1.93 to 2.21 liters/min) within the low group. Differences between groups were not statistically significant. Both groups also had comparable changes in heart rate, blood pressure and double-product at submaximal and maximal workloads. Analysis of blood lipids revealed that both groups experienced a significant increase in high density lipoprotein cholesterol. There were no significant changes in total serum cholesterol or triglycerides. These findings suggest that within an unselected population of patients after acute myocardial infarction referred for cardiac rehabilitation, low- and high-intensity exercise training produces relatively similar changes in cardiorespiratory variables during the initial 3 months of exercise training.