Purpose: Cardiorespiratory fitness (CRF) measured by peak oxygen consumption (VO 2 peak) declines with aging and correlates with mortality and morbidity. Cardiopulmonary Exercise Testing (CPET) is the criterion method to assess CRF, but its feasibility, validity and reliability in older adults is unclear. Our objective was to design and implement a dependable, safe and reliable CPET protocol in older adults.
Methods: VO 2 peak was measured by CPET, performed using treadmill exercise in 875 adults ≥70 years in the Study of Muscle, Mobility and Aging (SOMMA). The protocol included a symptom-limited peak (maximal) exercise and two submaximal walking speeds. An adjudication process was in place to review tests for validity if they met any prespecified criteria [VO 2 peak < 12.0 ml/kg/min; maximum heart rate (HR) <100 bpm; respiratory exchange ratio (RER) <1.05 and a rating of perceived exertion <15]. A subset (N = 30) performed a repeat test to assess reproducibility.
Results: CPET was safe and well tolerated, with 95.8% of participants able to complete the VO 2 peak phase of the protocol. Only 56 (6.4%) participants had a risk alert and only two adverse events occurred: a fall and atrial fibrillation. Mean ± SD VO 2 peak was 20.2 ± 4.8 mL/kg/min, peak HR 142 ± 18 bpm, and peak RER 1.14 ± 0.09. Adjudication was indicated in 47 tests; 20 were evaluated as valid, 27 as invalid (18 data collection errors, 9 did not reach VO 2 peak). Reproducibility of VO 2 peak was high (intraclass correlation coefficient = 0.97).
Conclusions: CPET was feasible, effective and safe for older adults, including many with multimorbidity or frailty. These data support a broader implementation of CPET to provide insight into the role of CRF and its underlying determinants of aging and age-related conditions.
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