Influence of exercise capacity on cardiolocomotor coupling during walking in young people

The specific mechanisms of coupling between cardiac and locomotor rhythms remain unclear. We speculated that a decline in the function of cardiovascular and/or locomotor systems would increase the coupling of these systems to respond to the energy demand during exercise and increase efficiency. We studied mechanisms of cardiolocomotor coupling and the exercise capacity in young healthy people. Methods: Twenty young, healthy people performed cardiopulmonary exercise testing using a bicycle ergometer to determine cardiopulmonary function. Further, the subjects underwent a treadmill walk test to record cardiolocomotor coupling strength on separate days. The R2 value is an index of cardiolocomotor coupling strength calculated from the step and corresponding R-R intervals during incremental speed walking. We divided subjects into two groups according to the strength of the R2 value (high and low R2 groups) and compared resting cardiac variables, autonomic indices, and cardiopulmonary exercise testing data between the two groups. Results: Peak oxygen uptake, oxygen pulse, and minute ventilation volume were significantly lower in the high R2 group than in the low R2 group. The high R2 group had smaller subjects with lower habitual exercise. No significant differences in other indices were observed between both groups. Conclusions: Our findings indicate that exercise capacity affect the dynamic interaction between cardiovascular and locomotor systems during exercise in young people.