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- Validation of StepTest4all for assessing cardiovascular capacity in young adultsPublication . Bragada, José A.; Bartolomeu, Raúl Filipe; Rodrigues, Pedro M.; Magalhães, Pedro; Bragada, João P.; Morais, J.E.Background: Cardiovascular capacity, expressed as maximal oxygen uptake (VO2max), is a strong predictor of health and fitness and is considered a key measure of physiological function in the healthy adult population. The purpose of this study was to validate a specific step test (StepTest4all) as an adequate procedure to estimate cardiovascular capacity in young adults. Methods: The sample was composed of 56 participants, including 19 women (aged 21.05 2.39 years, body mass = 57.50 6.64 kg, height = 1.62 0.05 m, body mass index = 22.00 2.92 kg/m2) and 37 men (aged 22.05 3.14 years, body mass = 72.50 7.73 kg, height = 1.76 0.07 m, body mass index = 23.34 2.17 kg/m2). Participants were included in one of the following groups: (i) the group used to predict the VO2max, and (ii) the group used to validate the prediction model. All participants performed the StepTest4all protocol. The step height and the intensity of the effort was determined individually. Heart rate and oxygen uptake were measured continuously during rest, effort, and recovery phases. The validation process included the following three stages: (i) mean data comparison, (ii) simple linear regression, and (iii) Bland–Altman analysis. Results: The linear regression retained, as significant predictors of the VO2max, sex (p < 0.001) and heart rate recovery for one minute (p = 0.003). The prediction equation revealed a high relationship between measurements (R2 = 63.0%, SEE = 5.58). The validation procedure revealed non-significant differences (p > 0.05) between the measured and estimated maximal oxygen uptake, high relationship (R2 = 63.3%), and high agreement with Bland–Altman plots. Thus, VO2max can be estimated with the formula: VO2max = 22 + 0.3 (HRR1min) + 12 (sex), where HRR1min is the magnitude of the HR decrease (bpm) in one minute immediately after the step was stopped, and sex: men = 1, women = 0. Conclusions: The StepTest4all is an adequate procedure to estimate cardiovascular capacity, expressed as VO2max, in young adults. In addition, it is possible to determine the qualitative level of cardiovascular capacity from the heart rate recovery for one minute, more specifically, poor: <20, moderate: 20 to 34, good: 35 to 49, and excellent: 50. This procedure has the benefit of being simple to apply and can be used by everyone, even at home, without specialist supervision.
- Net Heart Rate for Estimating Oxygen Consumption in Active AdultsPublication . Bragada, José A.; Magalhães, Pedro; São-Pedro, Eric; Bartolomeu, Raúl Filipe; Morais, J.E.The aim of this study was to verify the accuracy of predicting oxygen consumption (O-2) in predominantly aerobic activities based on net heart rate (netHR), sex, and body mass index (BMI) in active adults. NetHR is the value of the difference between the resting HR (HRrest) and the average HR value obtained during a given session or period of physical activity. These activities must be continuous, submaximal, and of a stabilized intensity. The magnitude of the netHR depends mainly on the intensity of the exercise. The HR is measured in beats per minute (bpm). A total of 156 participants, 52 women and 104 men, between the ages of 18 and 81, had their netHR and net oxygen intake (netVO(2)) assessed. There were 79 participants in group 1 (prediction sample) (52 males and 27 females). There were 77 people in group 2 (validation sample) (52 males and 25 females). The results of the multiple linear regression showed that netVO(2) (R-2 = 85.2%, SEE = 3.38) could be significantly predicted by sex (p < 0.001), netHR (p < 0.001), and BMI (p < 0.001). The Bland-Altman plots satisfied the agreement requirements, and the comparison of the measured and estimated netVO(2) revealed non-significant differences with a trivial effect size. We calculated the formula NetVO(2) (mL/(kgmin)) = 16 + 3.67 (sex) + 0.27 (netHR) - 0.57 (BMI) to predict netVO(2), where netVO(2) is the amount of oxygen uptake (mL/(kgmin)) above the resting value, netHR is the heart rate (beats per minute) above the resting value measured during exercise, sex is equal to zero for women and one for men, and BMI is the body mass index. In addition, based on the knowledge of VO2, it was possible to estimate the energy expenditure from a particular training session, and to determine or prescribe the exercise intensity in MET (metabolic equivalent of task).