V̇O₂peak estimation in people with overweight and obesity before and after a 14-week lifestyle intervention

This study aimed to investigate the validity and applicability of a non-exercise estimation of cardiorespiratory fitness using resting seismocardiography (SCG eV̇O₂peak) in people with overweight and obesity before and after a 14-week lifestyle intervention.

The study was carried out at a Folk high school that offers 14-week courses on lifestyle changes where participants live at the school and voluntarily participate in daily lectures and activities. Sixty-seven men and women with age and body mass index between 18 and 70 years and 25-50 kg·m^-2 were tested at baseline, and 52 had a follow-up test after 14 weeks. Testing included the determination of anthropometric variables, an SCG eV̇O₂peak at supine rest, and a gold standard V̇O₂peak test on a cycle ergometer until voluntary exhaustion.

Agreement analysis for V̇O₂peak at baseline (n = 67, SCG eV̇O₂peak: 26.9 ± 1.9 ml·min^-1·kg^-1, V̇O₂peak: 26.6 ± 1.6 ml·min^-1·kg^-1, mean ± 95% confidence interval) showed a bias of 0.3 ± 1.0 ml·min^-1·kg^-1 with 95% limits of agreement (LoA) ranging ± 9.8 ml·min^-1·kg^-1. A Pearson's correlation of r = 0.78 (p < 0.0001) and a standard error of estimate (SEE) of 5.0 ml·min^-1·kg^-1 were found between methods. At follow-up (n = 52), body mass was reduced by 6.6 ± 1.4 kg (p < 0.0001). V̇O₂peak increased by 3.3 ± 0.9 ml·min^-1·kg^-1 and 175 ± 78 ml·min^-1 and SCG eV̇O₂peak by 2.6 ± 0.8 ml·min^-1·kg^-1 and 93 ± 76 ml·min^-1 (two-way ANOVA repeated measure: intervention p < 0.0001, method p = 0.939 and interaction p = 0.125, relative V̇O₂peak). A Pearson's correlation of r = 0.37 (p < 0.05) was found between changes in relative V̇O₂peak but not for absolute V̇O₂peak r = 0.10 (p = 0.402).

The SCG method is accurate for estimating V̇O₂peak and appropriate for detecting group changes in both relative and absolute V̇O₂peak following a lifestyle intervention in people with overweight and obesity. Furthermore, the method can detect individual changes in V̇O₂peak but not independently of body mass changes. Yet, the applicability is still limited by the relatively large variation in LoA and SEE.