Changes in the reactive hyperemia index after continuous and interval exercise.

Area of Science:

• Exercise Physiology
• Cardiovascular Health
• Vascular Function

Background:

• High-intensity interval exercise (HIIE) is known to benefit macrovascular function.
• The impact of HIIE on microvascular function is less understood compared to moderate-intensity interval exercise (MICE).
• Peripheral artery tonometry is used to assess microvascular function via the reactive hyperemia index (RHI).

Purpose of the Study:

• To investigate the acute effects of HIIE versus MICE on microvascular function in healthy adults.
• To compare the changes in reactive hyperemia index (RHI) following different exercise intensities.

Main Methods:

• Ten healthy participants completed separate sessions of MICE and HIIE cycling.
• MICE involved 20 minutes at 60% maximum power output.
• HIIE included a 12-minute warm-up followed by an 8-minute Tabata protocol (20s high-intensity cycling, 10s rest).
• RHI was measured pre-exercise, immediately post-exercise, and 1 hour post-exercise.

Main Results:

• The reactive hyperemia index (RHI) significantly increased 1 hour after MICE compared to baseline (p=0.02).
• No significant improvement in RHI was observed 1 hour after HIIE.
• Heart rate responses differed between the two exercise conditions.

Conclusions:

• A single session of MICE enhanced microvascular function in healthy adults, as indicated by RHI.
• HIIE did not yield significant improvements in microvascular function in this study.
• Further investigation is required to elucidate the distinct effects of exercise intensity on macro- and microvascular adaptations.