title: Single session of sprint interval training elicits similar cardiac output but lower oxygen uptake versus ramp exercise to exhaustion in men and women.
abstract: Sprint interval training (SIT) elicits comparable long-term adaptations versus continuous exercise training (CEX) including increased maximal oxygen uptake (VO2max) and fat utilization. However, there is limited research examining acute hemodynamic responses to SIT. The aim of this study was to examine hemodynamic responses to low-volume SIT. Active men (n=6, VO2max = 39.8 ± 1.7 mL/kg/min) and women (n=7, VO2max = 37.3 ± 5.7 mL/kg/min) performed a ramp-based VO2max test (RAMP) to determine workload for the SIT session. Subjects returned within 1 wk and completed a session of SIT consisting of six 30-s bouts of "all-out" cycling at 130% maximal workload (Wmax) interspersed with 120 s of active recovery. Continuously during RAMP and exercise and recovery in SIT, VO2was obtained and thoracic impedance was used to estimate heart rate (HR), stroke volume (SV), and cardiac output (CO). Results revealed no significant differences in COmax (p = 0.12, 19.7 ± 2.4 L/min vs. 20.3 ± 1.8 L/min) but lower SVmax (p = 0.004, 110.4 ± 15.7 mL vs. 119.4 ± 15.5 mL) in RAMP versus SIT. HRmax from SIT (179.0 ± 11.8 b/min) was lower (p = 0.008) versus RAMP (184.4 ± 7.9 b/min). Peak VO2(L/min) was lower (p < 0.001) in response to SIT (2.43 ± 0.82 L/min) compared to RAMP (2.84 ± 0.82 L/min). Hemodynamic variables increased linearly across SIT bouts and remained significantly elevated in recovery. Sprint interval training consisting of 3 min of supramaximal exercise elicits similar CO yet lower VO2compared to RAMP.
authors: Department of Kinesiology, California State University-San Marcos San Marcos, CA USA.
authors: Trevor
authors: T
authors: Horn
authors: Department of Kinesiology, California State University-San Marcos San Marcos, CA USA.
authors: Garret
authors: G
authors: Roverud
authors: Department of Kinesiology, California State University-San Marcos San Marcos, CA USA.
authors: Kandice
authors: K
authors: Sutzko
authors: Department of Kinesiology, California State University-San Marcos San Marcos, CA USA.
authors: Melissa
authors: M
authors: Browne
authors: Department of Kinesiology, California State University-San Marcos San Marcos, CA USA.
authors: Cristina
authors: C
authors: Parra
authors: Department of Kinesiology, California State University-San Marcos San Marcos, CA USA.
authors: Todd A
authors: TA
authors: Astorino
keywords: VO2max; cardiac output; cycle ergometer; interval training; stroke volume