Postexercise hypotension and heart rate variability response after water- and land-based high-intensity interval exercise in prehypertensive obese men
Question
How do acute water-based and land-based high-intensity interval exercise affect postexercise hypotension, heart-rate variability, affect, enjoyment, and soreness in prehypertensive obese men?
Summary
In nine prehypertensive obese young men, single water- and land-based HIIT sessions both lowered blood pressure after exercise. Water-based HIIT produced longer systolic blood-pressure reductions, better late-session affect and enjoyment, less thigh soreness, and no adverse events in this small crossover study.
Methodology
- Nine young prehypertensive obese men completed water HIIE, land HIIE, and control sessions.
- 9 participants.
- Chest-deep water maximum-speed intervals.
- Work intervals: 30 s.
- Recovery: 4 min active recovery at 50-60% HRmax.
- Intensity: Maximum speed; achieved 93.7% +/- 5.5% HRmax.
- About 40-42.5 min including warm-up and cool-down.
- Single acute condition.
- Single session.
- Randomized crossover acute repeated-measures study
- Ambulatory blood pressure, Heart-rate variability, Enjoyment and affect, and Muscle soreness were tracked.
Outcomes
24 h BP
Both HIIE modalities reduced 24 h MAP; water HIIE reduced 24 h SBP.
Water SBP -9 mmHg, p<0.01; MAP -6.7 mmHg for both water and land, p<0.01.
Night BP
Both HIIE modalities lowered nighttime BP, with stronger systolic effects after water HIIE.
Water nighttime SBP -20.1 mmHg, DBP -14.2 mmHg, MAP -16.1 mmHg; all p<0.01.
HRV
No between-modality HRV differences; land HIIE showed more signs of slower autonomic recovery.
No significant HRV differences between water and land; land increased daytime LF/HF vs control.
Affect
Water HIIE produced better late-session affect and enjoyment and less soreness.
Final affect/enjoyment comparisons favored water; thigh soreness 1.1 +/- 1.5 vs 3.3 +/- 2.6, p<0.05.
Insights
- Water-based HIIT may be a lower-soreness option for higher-BMI users.
- Long active recoveries can still produce postexercise blood-pressure reductions.
- Affect and enjoyment may diverge from physiological intensity and should be tracked.
Limitations
- Very small sample.
- Young men only.
- Acute-only study.
- VO2 not directly measured during HIIE to confirm equal energy expenditure.
- Water temperature can affect BP response.
Safety
- No adverse events occurred in any trials.
- Water HIIE produced less anterior thigh soreness than land HIIE.
- One enrolled participant did not complete the study because of lack of time.