Heart Rate and Vasomotor Control during Exercise

Spontaneous baroreflex function and vascular changes were assessed in young adults during dynamical mild exercise. Windkessel time constant was assessed by two different methods: two-element windkessel model, and by an autoregressive (AR) model, while the baroreflex sensitivity (BRS, ms/mmHg) was assessed by the sequence method. Results showed a change in the baroreflex control of heart rate (HR) with the severity of exercise, as well as the resetting phenomenon. Methods used to estimate the windkessel time constant were poorly correlated. Subject by subject correlation was found between the BRS and the time constant derived from the AR model within exercise and recovery period. These results may suggest that reflex mechanisms controlling HR may also participate in controlling peripheral circulation or, viceversa, BRS is influenced by vascular tone.