Evaluating Seismocardiography as a Non-Exercise Method for Estimating Maximal Oxygen Uptake

The value of maximal oxygen uptake (VO_2MAX) is a key health indicator. Usually, VO_2MAX is determined with cardiopulmonary exercise testing (CPET), which is cumbersome and time-consuming, making it impractical in many testing scenarios. The aim of this study is to validate a novel seismocardiography sensor (Seismofit^®, VentriJect DK, Hellerup, Denmark) for non-exercise estimation of VO_2MAX.

A cohort of 94 healthy subjects (52% females, 48.2 (8.7) years old) were included in this study. All subjects performed an ergometer CPET. Seismofit^® measurements were obtained 10 and 5 min before CPET in resting condition and 5 min after exhaustion.

The CPET VO_2MAX was 37.2 (8.6) mL/min/kg, which was not different from the two first Seismofit^® estimates at 37.5 (8.1) mL/min/kg (p = 0.28) and 37.3 (7.8) mL/min/kg (p = 0.66). Post-exercise Seismofit^® was 33.8 (7.1) mL/min/kg (p < 0.001). The correlation between the CPET and the Seismofit^® was r = 0.834 and r = 0.832 for the two first estimates, and the mean average percentage error was 11.4% and 11.2%. Intraclass correlation coefficients between the first and second Seismofit^® measurement was 0.993, indicating excellent test-retest reliability.

The novel Seismofit^® VO_2MAX estimate correlates well with CPET VO_2MAX, and the accuracy is acceptable for general health assessment. The repeatability of Seismofit^® estimates obtained at rest was very high.