Nayor M; Shah RV; Tanguay M; Blodgett JB; Chernofsky A; Miller PE; Xanthakis V; Malhotra R; Houstis NE;
Velagaleti RS; Larson MG; Vasan RS; Lewis GD

American Journal of Cardiology. 157:56-63, 2021 10 15.
VI 1

Cardiorespiratory fitness (CRF) is intricately related to health status.
The optimal approach for CRF quantification is through assessment of peak
oxygen uptake (VO2), but such measurements have been largely confined to
small referral populations. Here we describe protocols and methodological
considerations for peak VO2 assessment and determination of volitional
effort in a large community-based sample. Maximum incremental ramp cycle
ergometry cardiopulmonary exercise testing (CPET) was performed by
Framingham Heart Study participants at a routine study visit (2016 to
2019). Of 3,486 individuals presenting for a multicomponent study visit,
3,116 (89%) completed CPET. The sample was middle-aged (54 +/- 9 years),
with 53% women, body mass index 28.3 +/- 5.6 kg/m2, 48% with hypertension,
6% smokers, and 8% with diabetes. Exercise duration was 12.0 +/- 2.1
minutes (limits 3.7to20.5). No major cardiovascular events occurred. A
total of 98%, 96%, 90%, 76%, and 57% of the sample reached peak
respiratory exchange ratio (RER) values of >=1.0, >=1.05, >=1.10, >=1.15,
and >=1.20, respectively (mean peak RER = 1.21 +/- 0.10). With rising peak
RER values up to =1.10, steep changes were observed for percent predicted
peak VO2, VO2 at the ventilatory threshold/peak VO2, heart rate response,
and Borg (subjective dyspnea) scores. More shallow changes for effort
dependent CPET variables were observed with higher achieved RER values. In
conclusion, measurement of peak VO2 is feasible and safe in a large sample
of middle-aged, community-dwelling individuals with heterogeneous
cardiovascular risk profiles. Peak RER >=1.10 was achievable by the
majority of middle-aged adults and RER values beyond this threshold did
not necessarily correspond to higher peak VO2 values.