Classification(s): Cardiac Rehabilitation; Exercise Training
Introduction: Existing guidelines for resistance activity (commonly assumed dangerous due to Valsalva maneuver) following a cardiac event are overly restrictive when considering, upon hospital discharge, a patient may be told "don't lift more than 5 pounds" and/or "wait 2-5 weeks to perform resistance training." Peak rate pressure product (PRPP), an indirect measure of myocardial work, obtained by the product of peak heart rate (PHR) / peak systolic blood pressure (PSBP) can be used as a maximal allowable threshold for participation in a cardiac rehabilitation program where a PRPP of less than 36,000 is considered clinically safe.
Purpose: To compare the myocardial work of a cardiac patient during the performance of treadmill walking and a chest press activity.
Design: Eleven subjects (2 female, 9 male), age 42-70 years, who had a MI, PCI, or MI/PCI and were referred to the Cardiac Rehabilitation Program at the Baylor Jack and Jane Hamilton Heart and Vascular Hospital (Dallas, TX), participated in activities including treadmill walking and the chest press during which measurements of PHR, PSBP, and PRPP were obtained.
Methods: Subjects performed an exercise tolerance test to determine initial treadmill walking speed. Testing was stopped when subjects reported "11" on the Borg RPE scale. A strength test was performed to determine estimated daily weight to be lifted on the chest press machine. For the duration of the multi-session protocol, treadmill speeds and chest press pounds were modified in parallel through consideration of standard exercise prescription guidelines. Each day, PHR, PSBP, and PRPP were measured during treadmill walking and chest press activities. The adjusted Huynh and Feldt F test was used to determine if performance of the chest press leads to a significantly higher PHR, PSBP, or PRPP when compared with treadmill walking.
Results: PHR during the chest press is significantly lower (P = .050) than that during treadmill walking. PSBP during the chest press is not significantly lower (P = .113) when compared to treadmill walking. PRPP is significantly lower (P = .010) during the chest press than during treadmill walking.
Conclusions: Findings suggest that subjects endure less myocardial strain when performing the chest press than when walking on a treadmill. Traditional thinking is that that the PSBP would be higher during the chest press (due to the Valsalva maneuver), when, in actuality, increased PHR during treadmill walking was the factor that generated compelling differences in PRPP.