Introduction: Assessment of maximal oxygen consumption (V̇O2max) is considered an important clinical tool when examining both healthy and unhealthy populations, as a low V̇O2max is associated with cardiovascular disease and all-cause mortality.
Aims: This study aimed to investigate the accuracy of a clinical non-exercise test for assessment of VO2max using seismocardiography (SCG). Methods: A total of 97 healthy participants (50 males) within the age of 20-45 years underwent a non-exercise test using SCG at rest in the supine position (SCG V̇O2max) and a graded exercise test to voluntary exhaustion on a cycle ergometer with indirect calorimetry (IC V̇O2max). SCG V̇O2max was predicted by an algorithm using amplitudes and timing intervals extracted from the SCG in combination with demographic data. An interim analysis was applied after 50 participants had completed testing (SCG V̇O2max 1.0) allowing for the algorithm to be modified (SCG V̇O2max 2.1). Results: SCG V̇O2max 2.1 (n=97) was 2.2 ± 1.1 ml/min/kg (mean ± 95% CI) lower than IC V̇O2max (p<0.001) (44.0 ± 1.1 ml/min/kg and 46.2 ± 1.4 ml/min/kg, respectively), with a positive correlation (Pearson, r=0.66, p<0.0001) and a coefficient of variation (CV) of 7 ± 1% between tests. (Interim analyses: SCG V̇O2max 1.0 (n=50); -1.7 ± 1.5 ml/min/kg (p=0.028), r=0.60 (p<0.0001), CV= 7 ± 1% and SCG V̇O2max 2.1 (n=47); -3.5 ± 1.8 ml/min/kg (p<0.001), r=0.65 (p<0.0001), CV= 8 ± 1% compared with IC V̇O2max). Conclusion: The accuracy of V̇O2max assessment using seismocardiography requires further optimization prior to clinical application, as SCG V̇O2max was systematically lower than the golden standard measurement with indirect calorimetry, and a moderate correlation together with considerable variations were observed between tests. Ongoing development of the algorithm is in progress in order to improve the accuracy of V̇O2max estimation using seismocardiography.