Prolonged Improvement In Hemodynamic Parameters At Rest And During Stress Testing After High-intensity Interval Training

Abstract

PURPOSE: As demonstrated earlier, one bout of aerobic exercise has been shown to result in a prolonged lowering of peripheral and central blood pressure (BP) and pulse wave velocity (PWV) in normotensive and hypertensive individuals. Therefore, a study was initiated to evaluate if faster and more intense forms of exercise, such as HIIT, can also bring about similar blood pressure and PWV reductions. Since cardiovascular hyper-reactivity to stress has a higher prognostic value than measurements conducted at rest, the responses during a following cold pressor test (CPT) were studied as well. METHODS: In 39 healthy men (34±8 years, BMI 24±2 kg/m2) peripheral BP (pBP), central BP (cBP) and PWV were measured non-invasively at rest and at the end of a 2 minute CPT using 24 PWA monitor. Following a HIIT (6 x 1 min., 98% of previously determined maximum workload, 4 min. rest between intervals) pBP, cBP and PWV were measured throughout 60 minutes of rest and thereafter during a CPT. RESULTS: Even 45 minutes after HIIT, there was a significant reduction in systolic pBP (127±9 mmHg to 124±10 mmHg; p=0.029), systolic cBP (116±8 mmHg to 112±9 mmHg; p=0.003) and PWV (5.92±0.7 m/sec. to 5.84±0.7 m/sec.; p=0.037) compared with pre-exercise. Furthermore there were significant reductions in diastolic pBP (81±8 mmHg to 79±7 mmHg; p=0.031) compared to pre-exercise as well. Moreover, pBP (144±13/96±12 mmHg to 137±12/93±11 mmHg), cBP (130±13/98±12 mmHg to 125±12/94±11 mmHg) and PWV (6.4±0.7 m/sec to 6.2±0.8 m/sec.) during CPT after HIIT were significantly (p<0.01) lower when compared with pre-exercise measurements. 60 minutes after exercise, there were no more significant differences compared with pressures at rest before exercise. In contrast, 60 minutes after HIIT the increases in systolic pBP (Δ = 16.2±10 mmHg vs. Δ = 11.8±11 mmHg; p=0.019), systolic cBP (Δ = 14.5±11 mmHg vs. Δ = 9.8±11 mmHg; p=0.017) and PWV (Δ = 0.47±0.36 m/sec. vs. Δ = 0.29±0.42 m/sec; p=0.026) due to CPT were still significantly lower when compared with measurements during CPT before exercise. CONCLUSION: HIIT leads to a reduction in pBP, cBP and PWV, which was still established 45 minutes after completion of the training. Moreover, pressures and PWV during a CPT increased less after HIIT, indicating attenuated hemodynamic response to stress testing after a single HIIT-session.