Effects of aerobic exercise training in community-based subjects aged 80 and older: a pilot study.

OBJECTIVES: To assess the ability of sedentary, frail subjects aged 80 and older to train in a community-based exercise program and to evaluate clinical factors that predict improvements in peak oxygen consumption (VO2peak). DESIGN: Pretest, posttest. SETTING: Charlestown Retirement Community, Catonsville, Maryland PARTICIPANTS: Twenty-two (11 male, 11 female; mean age +/- standard deviation = 84 +/- 4.0, range 80-92) self-referred. INTERVENTION: Six months of moderate-intensity aerobic exercise training, two to three sessions/week, 20 to 30 minutes per session. Training modes included treadmill walking and/or stationary cycling. MEASUREMENTS: Baseline and follow-up maximal exercise treadmill tests (ETTs) with electrocardiogram monitoring and respiratory gas analysis. RESULTS: Six months of aerobic exercise training resulted in significant increases (mean +/- standard deviation) in ETT duration (11.9 +/- 3.3 vs 15.9 +/- 4.3 minutes; P =.01), VO2peak (1.23 +/- 0.37 vs 1.31 +/- 0.36 L/min; P =.04), and oxygen pulse (9.3 +/- 2.8 vs 10.1 +/- 3.2; P =.03). Mean heart rate was significantly lower during submaximal ETT stages 1 through 4 (P <.05), and resting systolic blood pressure decreased (146 +/- 18 vs 133 +/- 14 mmHg; P =.01) after training. Multiple regression analysis indicated that baseline VO2peak (r = 0.75, P =.002) and the total amount of time spent in exercise training (r = 0.55, P =.008) were independent predictors of the training-related improvements in VO2peak. CONCLUSION: Subjects aged 80 and older can increase aerobic capacity and reduce systolic blood pressure in a community-based exercise program of moderate intensity. The most important predictors of change in VO2peak were baseline VO2peak and the time spent in exercise training. Subjects with a lower baseline VO2peak had the greatest improvements in VO2peak after training.

Role of nondiagnostic exercise-induced ST-segment abnormalities in predicting future coronary events in asymptomatic volunteers.

BACKGROUND: Whether exercise-induced ST-segment depression <1 mm is an independent predictor of future coronary events (CEs) in asymptomatic subjects is unknown. METHODS AND RESULTS: We performed maximal treadmill exercise tests on 1083 volunteers from the Baltimore Longitudinal Study of Aging who were free from clinical coronary heart disease. Exercise ST-segment changes were stratified by Minnesota code criteria: 11:1 (n=213), flat or downsloping ST depression > or =1 mm; 11:2 (n=66), flat or downsloping ST depression > or =0.5 mm and <1 mm; 11:4 (n=124), ST-J depression > or =1 mm with slowly rising ST segments; and 11:5 (n=69), minor ST depression (<0.5 mm) before exercise that worsened to flat or downsloping ST depression > or =1 mm during or after exercise. Risk of CE was compared with subjects with normal exercise ECG (n=611). Over a mean follow-up of 7.9 years, 76 subjects developed CEs (angina pectoris, myocardial infarction, or coronary death). On univariate analysis, age (relative risk [RR]=1.07/year, P<0.0001), male sex (RR=1.98, P=0.009), plasma cholesterol (RR=1.02/mg per dL, P<0.0001), hypertension (RR=2.23, P=0.002), duration of exercise (RR=0.71/min, P=0.0001), and systolic blood pressure at peak effort (RR=1.02/mm Hg, P=0.002) were associated with CE. By Cox proportional hazards analysis, age (RR=1.06/year, P<0.0001), male sex (RR=2.76, P=0.0002), plasma cholesterol (RR=1.02 per 1 mg/dL, P<0.0001), duration of exercise (RR=0.87/min, P=0.004), and ST-segment changes coded as either 11:1 (RR=2.70, P=0.0005) or 11:5 (RR=2.73, P=0.04) were independent predictors of CE. CONCLUSIONS: Both a classic ischemic ST-segment exercise response and intensification of minor preexercise ST-segment depression to levels > or =1 mm independently predicted future CE in this asymptomatic population. Neither slowly rising ST depression nor horizontal ST depression <1 mm was prognostic.

Attenuated cardiovascular reserve during prolonged submaximal cycle exercise in healthy older subjects.

OBJECTIVE: The goal of this study was to determine the effect of age on the hemodynamic response to prolonged submaximal aerobic exercise in healthy volunteers. BACKGROUND: Reductions in peak work rate, heart rate (HR), and left ventricular (LV) emptying but higher blood pressure (BP) and systemic vascular resistance occur in healthy older versus younger humans during short bursts of graded maximal aerobic exercise. However, the effect of aging on the cardiovascular response to prolonged exercise at submaximal work rates typical of daily aerobic activities remains unknown. METHODS: We evaluated cardiovascular performance throughout prolonged submaximal upright cycle ergometry in 40 carefully screened healthy untrained volunteers, 8 men and 12 women <50 years old, mean = 37 +/- 8 years (younger), and 10 men and 10 women >/=50 years old, mean = 66 +/- 9 years (older), during upright cycle exercise at 70% of peak cycle oxygen consumption (VO(2)) to exhaustion or a maximum of 120 min. Cardiac volumes were acquired by gated blood pool scans with (99m)Tc at rest and every 10 min throughout exercise. RESULTS: Duration of exercise was similar in younger ([81 +/- 28 min] versus older [71+/- 29 min] subjects, p = NS). At 10 min of exercise in the steady state, older subjects demonstrated lower VO(2) (1.1 +/- 0.2 l/min vs. 1.3 +/- 0.3 l/min) and lower HR (118 +/- 17 vs. 135 +/- 11 beats/min, p < 0.001) but larger end-diastolic (80 +/- 11 ml/m(2) vs. 73 +/- 8 ml/m(2), p = 0.03) and end-systolic volume index (ESVI) 20 +/- 6 ml/m(2) vs. 17 +/- 4 ml/m(2), p < 0.05) than younger ones. Between 10 min and exercise termination, with VO(2) held constant in both groups, increases in HR (14.0 +/- 12.4 beats/min vs. 5.9 +/- 11.5 beats/min, p = 0.04), cardiac index (1.6 +/- 1.0 l/min/m(2) vs. 0.8 +/- 1.1 l/min/m(2), p = 0.03), and LV ejection fraction (7.1 +/- 4.0% vs. 2.9 +/- 4.4%, p = 0.003) were greater in younger than older subjects, respectively, as was the reduction in ESVI (-5.1 +/- 3.0 ml/m(2) vs. -1.8 +/- 3.3 ml/m(2), p = 0.002), despite similar declines in systolic BP (-12.3 +/- 6.3 mm Hg vs. -12.1 +/- 15.0 mm Hg, p = NS). CONCLUSIONS: Thus, age-associated deficits in chronotropic and LV systolic reserve performance occur during prolonged submaximal upright cycle ergometry, analogous to those observed during graded maximal exercise.