The Efficacy of Graded Exercise Stress Testing to Age Predicted Maximum Heart Rate in Men 65 Years and Older

Abstract

Clinical graded exercise stress tests (GXT) are typically terminated when patients reach 85% of age predicted maximum heart rate (APMHR). However, if older adults are tested to levels greater than 85% of APMHR, it is unknown whether underlying cardiac disease may be revealed. PURPOSE: To examine the diagnostic benefit of performing GXT's to maximal physical capacity in community dwelling, at risk, older men. METHODS: As part of the entry criteria for an intervention study, 40 older men: 30 Caucasian, six Hispanic, two Asian, one Black, one unspecified (age: 65–85 years, height: 1.44–1.86m, weight: 55.3–114.5kg, BMI: 20.8–38.6) performed a GXT on a cycle-ergometer following a ramping protocol to physical exhaustion or until contraindications (ST-segment changes, ischemia, or serious arrhythmia) for stopping the test were observed. The required criteria for passing the GXT included: 1) No pathological ST-segment changes, 2) No serious arrhythmia or ectopy, 3) Reaching 85% of APMHR. RESULTS: Thirty-four of the 40 participants met the passing criteria for the GXT. Reasons for failing the GXT included: 1) The inability of subjects (n = 5) to reach 85% of APMHR (range 72–82%) were due to leg pain or fatigue and 2) One subject demonstrating a ST-segment change one-minute into exercise recovery after achieving 112% of APMHR. With exception to the single ST-segment change in recovery, encouraging subjects to continue the test beyond 85% of APMHR did not reveal underlying heart disease. CONCLUSION: These data indicate that GXT's performed to age predicted maximum heart rate on a cycle-ergometer in an older, at risk population are safe to perform; however, there appears to be limited diagnostic benefit compared to tests terminated at 85% of APMHR.Table