Detecção do limiar anaeróbio a partir da variabilidade da frequência cardíaca durante exercício físico progressivo tipo rampa em adultos jovens

Abstract

The objective of this research was to assess low cost mathematical tools for determining the anaerobic threshold from heart rate variability signals. We developed and tested the methods Cusum, Spectral and RARMA derived from parametric and non-parametric models.We studied 46 young adults men aged 20 to 39 years, sedentary,normotensive, non-cardiac, non-diabetic, non-smokers, not-drinkers, and with body mass index between 18 and 30 kg/m2. The volunteers performed the cardiopulmonary test with submaximal effort inan ergometric treadmill. It was used a ramp protocol with increments of speed and incline performed by an individual according to age. The beat to beat data were obtained from heart rate monitor. The anaerobic threshold was determined by three specialists from the analysisof ventilatory visual graphic. This method was considered the gold standard for detecting the anaerobic threshold. Subsequently, the anaerobic threshold was determined by the methods developed in this work and the results were compared with the gold standard.We used the Pearson and Spearman tests of correlation (significance level of 0.01) and found significant correlations (r > 0.70) between the value of heart rate identified by mathematical models Spectral and RARMA. Therefore, in the study group, both mathematical models were effective in non-invasive determination of anaerobic threshold. The correlation of the Cusum method with the gold standard was 0.62 and was not considered satisfactory.