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.