Cardiovascular Autonomic Modulation after Acute High Intensity Interval versus Aerobic Exercise

Abstract

Little is known about autonomic modulation following high intensity interval exercise. PURPOSE: To compare cardiovascular autonomic modulations following acute high intensity interval versus endurance exercise. METHODS: Twenty five (∼25 y), endurance trained subjects completed a high intensity interval exercise session (IE) and an aerobic exercise session (AE) in randomized order on separate days. Beat-to-beat BP was recorded for 5 min in a supine position prior to exercise (PRE) and at 30 min (P30) and 60 min (P60) following exercise. Baroreceptor sensitivity (BRS) was analyzed by sequence (up-up and down-down) and spectral methods (transfer function, Alpha-high frequency and low frequency). Frequency domain of heart rate variability was derived from beat-to-beat BP data. Natural log-transformed heart rate high frequency (In HF) and low frequency (In LF) oscillations were calculated. Carotid BP was assessed using applanation tonometry at PRE, P30 and P60. RESULTS: Data presented in Table 1 as Mean (SE). The decrease in BRS and HRV post exercise was greater following IE than AE.TABLE 1: NO caption available.CONCLUSIONS: IE and AE elicit differential autonomic responses, demonstrated by lower parasympathetic modulation with altered BRS after interval exercise. These post-exercise responses may be related to an increase in carotid BP following IE. These data suggest that the vagal rebound during recovery from exercise is reduced or delayed following acute high intensity compared to acute endurance exercise.