Regional changes in reactive hyperemic blood flow during exercise training: time-course adaptations

Area of Science:

• Exercise physiology
• Cardiovascular research
• Human physiology

Background:

• Limited research exists on the temporal effects of localized exercise on regional blood flow.
• This study investigates how handgrip exercise training impacts forearm reactive hyperemia and vascular resistance.

Purpose of the Study:

• To determine the time course of changes in forearm reactive hyperemic blood flow and vascular resistance following unilateral handgrip exercise training.
• To assess the effects of localized training on vascular function in healthy men.

Main Methods:

• Strain gauge plethysmography was used to measure forearm blood flow and vascular resistance in 17 healthy men.
• Measurements were taken at rest and after arterial occlusion, weekly for 4 weeks, before and during training.
• Participants performed unilateral handgrip exercise training (5 days/week, 20 minutes, 60% MVC) on the non-dominant arm, with the dominant arm serving as a control.

Main Results:

• Handgrip exercise training increased trained arm strength (14.5%) and circumference (1.56%).
• A significant interaction between arm and visit was found for reactive hyperemic blood flow and vascular resistance.
• Reactive hyperemic blood flow increased (p=0.0013) and post-occlusion vascular resistance decreased (p=0.05) after the first week of training, with no further changes observed.

Conclusions:

• One week of unilateral handgrip exercise training leads to significant improvements in forearm reactive hyperemia and vascular resistance.
• These vascular adaptations in the trained arm plateaued after the initial week of training and did not progress further over the 4-week study period.