BACKGROUND: The analysis of the kinetic responses of heart rate (HR) and oxygen consumption (VO2) are an important tool for the evaluation of exercise performance and health status.
OBJECTIVES: The purpose of this study was to investigate the effects of aging on the HR and VO2 kinetics during the rest-exercise transition (on-transient) and the exercise-recovery transition (off-transient), in addition to investigating the influence of exercise intensity (mild and moderate) on these variables.
METHOD: A total of 14 young (23±3 years) and 14 elderly (70±4 years) healthy men performed an incremental exercise testing (ramp protocol) on a cycle-ergometer to determine the maximal power (MP). Discontinuous exercise testing was initiated at 10% of the MP with subsequent increases of 10% until exhaustion. The measurement of HR, ventilatory and metabolic variables and blood lactate were obtained at rest and during the discontinuous exercise.
RESULTS: The lactate threshold was determined in each subject and was similar between the groups (30±7% of MP in the young group and 29±5% of MP in the elderly group, p>0.05). The HR and VO2 kinetics (on- and off-transient) were slower in the elderly group compared to the young group (p<0.05). Additionally, in the young group, the values of HR and VO2 kinetics were higher in the moderate compared to the mild exercise intensity.
CONCLUSION: We concluded that the elderly group presented with slower HR and VO2 kinetics in relation to the young group for both on- and off-transients of the dynamic exercise. Moreover, in the young group, the kinetic responses were slower in the moderate intensity in relation to the mild intensity.
