Nancy A. Wilke

Response of patients after myocardial infarction to carrying a graded series of weight loads

Cardiovascular responses to carrying graded weight loads of 20 to 50 pounds were determined in 52 patients after myocardial infarction (MI) (greater than or equal to 2 months). Sixty percent of the patients were stopped before completing the heaviest weight load (50 pounds for 2 minutes) because of an increase in diastolic blood pressure (BP) to 120 mm Hg (end point) or arm fatigue. Compared with symptom-limited graded dynamic exercise, peak systolic and diastolic BP were significantly greater (p less than 0.05 and p less than 0.01, respectively) with weight carrying, while peak heart rate, pressure-rate product, ventilation and oxygen consumption were significantly lower (p less than 0.01). Ischemic responses were less frequent with weight carrying. Patients with severely reduced resting left ventricular ejection fraction (LVEF) (less than 35%) tolerated the weight carrying test as well as patients with normal resting LVEFs (greater than 50%). We conclude that (1) ischemic responses occur less frequently while carrying up to 50 pounds for 2 minutes than with symptom-limited dynamic exercise, (2) a significant number of patients have an increase in diastolic BP greater than or equal to 120 mm Hg while carrying objects that weigh 30 to 50 pounds for 2 minutes, and (3) a poor correlation exists between resting LVEF and tolerance for weight carrying.

Effect of age and coronary artery disease on response to snow shoveling.

Objectives. The objective of this study was to evaluate the effect of age and coronary artery disease on responses to snow shoveling. Background. Little information is available on the hemodynamic and metabolic responses to snow shoveling. Methods. Sixteen men with asymptomatic coronary artery disease and relatively good functional work capacity, 13 older normal men and 12 younger normal men shoveled snow at a self-paced rate. Oxygen consumption, heart rate and blood pressure were determined. In nine men with coronary artery disease left ventricular ejection fraction was evaluated with an ambulatory radionucilde recorder. Results. Oxygen consumption during snow shoveling differed (p < 0.05) among groups; it was lowest (18.5 ± 0.8 ml/kg per min) in those with coronary artery disease, intermediate (22.2 ± 0.9 ml/kg/min) in older normal men and highest (25.6 ± 1.3 ml/kg/min) in younger normal men. Percent peak treadmill oxygen consumption and heart rate with shoveling in the three groups ranged from 60% to 68% and 75% to 78%, respectively. Left ventricular ejection fraction and frequency of arrhythmias during shoveling were similar to those during treadmill testing. Conclusions. During snow shoveling 1) the rate of energy expenditure selected varied in relation to each mans peak oxygen consumption; 2) older and younger normal men and asymptomatic men with coronary artery disease paced themselves at similar relative work intensities; 3) the work intensity selected represented hard work but was within commonly recommended criteria for aerobic exercise training; and 4) arrhythmias and left ventricular ejection fraction were similar to those associated with dynamic exercise.

The safety of static-dynamic effort soon after myocardial infarction

Many activities of daily living require static-dynamic effort. To evaluate the safety of such effort 3 weeks after myocardial infarction, 27 male patients underwent a weight-carrying test requiring 5 minutes of treadmill ambulation with graded weight loads of 10 to 30 pounds. The hemodynamic responses with weight carrying were compared to that of a predischarge graded dynamic exercise test. The peak heart rate was significantly lower (p less than 0.01) with weight carrying, the peak systolic blood pressure did not differ, and the diastolic pressure was significantly higher (P less than 0.01). ST segment depression and angina pectoris occurred less frequently with weight carrying. The type and frequency of ventricular arrhythmias were similar between the two tests. We conclude that many men are capable of performing static-dynamic activity equivalent to carrying up to 30 pounds by 3 weeks after myocardial infarction.

Weight carrying versus handgrip exercise testing in men with coronary artery disease.

The clinical merits of handgrip and weight carrying tests were compared in 30 patients with documented coronary artery disease. The static loads in the 2 tests were matched by percentage of maximal static effort and corresponded to 25 and 45% of maximal voluntary handgrip contraction and 25 and 45% of maximal 1-hand lift capacity. Each static load in both tests was continued for less than or equal to 3 minutes. At the 25% maximal effort stage, 93 and 90% of patients were able to complete 3 minutes of handgrip and weight carrying, respectively. Only 13 and 10% were able to complete 3 minutes at the 45% maximal effort stage with handgrip and weight carrying, respectively. Arm fatigue and an increase in diastolic blood pressure greater than 120 mm Hg were the predominant endpoints. Weight carrying resulted in significantly higher (p less than 0.05) heart rate, systolic blood pressure, pressure-rate product, ventilation and oxygen consumption compared to handgrip. Diastolic blood pressure responses did not differ between the tests. None of the patients demonstrated ischemic responses to either handgrip or weight carrying and the incidence of arrhythmias was rare. The diastolic blood pressure response to static effort is equally evaluated by handgrip and weight carrying tests. However, the greater myocardial oxygen demand, reflected by the pressure-rate product, in addition to the greater total body oxygen consumption, imposed by weight carrying, enhances the clinical application of the weight carrying test.

Snow blowing and shoveling in normal and asymptomatic coronary artery diseased men

We evaluated the oxygen uptake and heart-rate responses to self-paced snow blowing and snow shoveling in 10 men with asymptomatic coronary artery disease, 10 older normal men, and six younger normal men. Mean peak treadmill oxygen uptake in the three groups ranged from 26.4 +/- 1.1 to 47.3 +/- 3.9 ml/kg per min (P < 0.05). Oxygen uptake during snow blowing did not differ significantly among subject groups; values were 17.1 +/- 1.3, 17.7 +/- 1.1, and 17.2 +/- 0.9 ml/kg per min in the coronary artery disease, older normal, and younger normal groups, respectively. Oxygen uptake with snow shoveling was lower (P < 0.05) in those with coronary artery disease (18.4 +/- 1.0 ml/kg per min) than in the normal groups. In comparison with snow shoveling, oxygen uptake and heart rate did not differ (P = NS) from snow blowing in the coronary artery disease group but were lower (P < 0.05) with snow blowing in the two normal groups. The results indicate that men with asymptomatic coronary artery disease and relatively good functional work capacity perform snow blowing and snow shoveling at similar levels of oxygen uptake and heart rate.

Physiologic responses to shoveling and thermal stress in men with cardiac disease.

To investigate the effect of temperature stress on responses to static-dynamic work in patients with ischemic heart disease (IHD), 10 men with IHD shoveled gravel for 30 min in a warm (29 degrees C), neutral (24 degrees C), and cold (-8 degrees C) environment (on separate days). A pace of 15 lifts.min-1 was set, and the load per lift approximated 5.5 kg. Heart rate (HR), oxygen consumption (VO2), and systolic (SBP) and diastolic blood pressures (DBP) were evaluated at 5-min intervals. Arrhythmias and ST-segment depression were evaluated by ambulatory electrocardiographic monitoring. At 30 min, VO2, SBP, and DBP were higher (P < 0.05) in the cold environment, and HR was higher (P < 0.05) in the warm environment compared with the neutral environment. HR increased (P < 0.05) from 5 to 30 min in all three conditions. The increase in HR was greater (P < 0.05) in the warm environment. None of the subjects reported angina or demonstrated electrocardiographic ST-segment changes during shoveling in any environment. The results indicate that low-risk patients with stable IHD show modest temperature-induced alterations in hemodynamic and VO2 responses during 30 min of moderate intensity (50-60% of peak VO2) static-dynamic work without adverse electrocardiographic responses or symptomatology.

Responses of people with coronary artery disease to common lawn-care tasks.

AbstractThe primary purpose of the present study was to determine oxygen uptake (

Exercise Prescription for Return to Work

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