Validation of the Cosmed Fitmate for predicting maximal oxygen consumption

The primary purpose of this study was to assess the validity of the Cosmed Fitmate (FM) in predicting maximal oxygen consumption (VO_2max), compared to the Douglas bag (DB) method. In addition, this study examined whether measuring submaximal VO₂, rather than predicting it, can improve upon the prediction of VO_2max. Thirty-two males and sixteen females (Mean ± SD: age 31 ± 10 yr, body mass 72.9 ± 13.0 kg, height 1.75 ± 0.09 m, BMI 23.4 ± 3 kg·m^-2) volunteered to participate in the study. Each participant completed a submaximal and a maximal treadmill test using the Bruce protocol on two separate occasions. During the submaximal test, VO_2max was predicted using the FM, while during the maximal test VO_2max was measured using the DB method. The Cosmed Fitmate predicts VO2max by extrapolating the linear regression relating heart rate and measured VO₂ to age-predicted maximum heart rate (HR = 220-age). This study also examined the validity of predicting VO_2max by using the ACSM metabolic equations to estimate submaximal VO₂. VO_2max values from the FM, the DB method, and ACSM prediction equations were analyzed using repeated measures ANOVA and linear regression analyses. The level of significance was set at P < 0.05 for all statistical analyses. There was no significant difference between VO_2max predicted by the FM (45.6 ml·kg^-1·min^-1, SD 8.8) and measured by the DB method (46.5 ml·kg^-1·min^-1, SD 8.8) (p = 0.152). The results of this study showed that a strong positive correlation (r = 0.897) existed between VO_2max predicted by the FM and VO_2max measured by the DB method, with a standard error of the estimate (SEE) = 3.97 ml·kg^-1·min^-1. There was a significant difference in VO_2max predicted by the ACSM metabolic equations (51.1 ml·kg-1·min-1, SD 7.98) and VO_2max measured by the DB method (p = 0.01). The correlation between these variables was r = 0.758 (SEE = 5.26 ml·kg^-1·min^-1). These findings suggest that the Fitmate is a small, portable, and easy-to-use metabolic system that provides reasonably good estimates of VO_2max, and that measuring submaximal VO₂, rather than predicting it from the ACSM metabolic equations, improves the prediction of _2max.