PMID 33013285

Research
All papers

High-Intensity Interval Training Decreases Muscle Sympathetic Nerve Activity in Men With Essential Hypertension and in Normotensive Controls

Ehlers TS, Sverrisdottir Y, Bangsbo J, Gunnarsson TP

Question

Does 6 weeks of 10-20-30 cycling HIIT reduce muscle sympathetic nerve activity, blood pressure, fat mass, and fitness markers in men with essential hypertension and normotensive controls?

Summary

In 24 sedentary older men, 6 weeks of supervised 10-20-30 cycling HIIT reduced resting muscle sympathetic nerve activity in both hypertensive and normotensive groups. Nighttime diastolic and mean arterial blood pressure fell in hypertensive men, body fat improved in both groups, and the authors discussed HIIT as time-efficient, though the study was small and male-only.

Methodology

  • 14 sedentary men with essential hypertension and 10 age-matched normotensive sedentary men.
  • 24 participants.
  • Stationary cycling.
  • Work intervals: 10 s maximal sprint.
  • Recovery: 30 s low-intensity plus 20 s moderate-intensity cycling; 3 min passive rest between bouts.
  • Intensity: Low 30-80 W, moderate 50-120 W, maximal sprint >300 W.
  • Less than 25 min including warm-up.
  • 2 sessions/week in weeks 1-2, then 3 sessions/week.
  • 6 weeks.
  • Non-randomized pre-post intervention study with hypertensive and normotensive groups
  • MSNA, Nighttime BP, Body composition, and Fitness were tracked.

Outcomes

MSNA

Resting MSNA burst frequency decreased in both hypertensive and normotensive men.

HYP -6 +/- 7 bursts/min; NORM -8 +/- 9 bursts/min; p<0.05, no between-group difference.

Improved

Night BP

Nighttime diastolic and mean arterial BP decreased in hypertensive men only.

HYP DBP -4.0 +/- 6.3 mmHg and MAP -3.5 +/- 6.9 mmHg, p<0.05.

Improved

Body fat

Body mass, visceral fat, and fat percentage decreased in both groups.

Within-group p<0.05; fat-free mass unchanged.

Improved

VO2max

VO2max increased only in normotensive men; GXT performance improved in both groups.

VO2max group-by-time interaction p<0.05; GXT time improved p<0.01 in both groups.

Mixed

Insights

  • 10-20-30 cycling concentrates high-intensity work into 100-150 seconds per session.
  • Cycling can reduce impact risk for older or clinical-risk users.
  • Medication and pathology may blunt VO2max response even when BP and MSNA improve.

Limitations

  • Men only.
  • Small sample.
  • No randomized non-training control.
  • Many hypertensive participants used antihypertensive medication.
  • No long-term follow-up.

Safety

  • Cycling was chosen to minimize injury risk.
  • All training sessions were supervised and heart rate monitored.
  • No cohort-specific adverse-event table was found in the reviewed text.