How does hand grip affect systemic vascular resistance?

From the Guidelines

Hand grip increases systemic vascular resistance due to the isometric nature of the exercise, which imposes a significant pressure load on the cardiovascular system.

Key Points

• Isometric exercise, such as hand grip, increases both systolic and diastolic blood pressure, resulting in a moderate increase in cardiac output and a disproportionate rise in peripheral vascular resistance 1.
• The increased resistance in active muscle groups limits blood flow, and cardiac output is not increased as much as in isotonic exercise 1.
• However, hand grip exercise may also increase blood flow to the forearm, potentially enhancing vein maturation and increasing flow through a fistula created using these vessels 1.

Mechanism

The mechanism behind the increase in systemic vascular resistance during hand grip exercise is thought to be due to reflex vasoconstriction, which occurs in response to the increased intramuscular pressure and muscle ischemia caused by the contraction 1.

• This vasoconstriction, combined with the increased cardiac output, results in a significant pressure load on the cardiovascular system.
• The increase in peripheral vascular resistance is proportional to the force exerted during the hand grip exercise, with higher forces resulting in greater increases in resistance 1.

From the Research

Hand Grip and Systemic Vascular Resistance

• Hand grip has been shown to affect systemic vascular resistance, with studies indicating that isometric handgrip exercise increases systemic vascular resistance 2, 3.
• The increase in systemic vascular resistance during handgrip exercise is associated with an increase in mean arterial pressure and a decrease in cardiac output 2, 4.
• The mechanisms underlying the increase in systemic vascular resistance during handgrip exercise are complex and involve the activation of the sympathetic nervous system and the release of vasoconstrictor substances 5, 3.
• Individual differences in cardiac and vascular components of the pressor response to isometric handgrip exercise have been observed, with some individuals showing a greater increase in cardiac output and others showing a greater increase in total peripheral resistance 3.
• Handgrip strength has been shown to be associated with specific aspects of vascular function, including arterial stiffness and peripheral vascular resistance, in individuals with metabolic syndrome 6.

Key Findings

• Isometric handgrip exercise increases systemic vascular resistance by 10-20% 2, 3.
• The increase in systemic vascular resistance during handgrip exercise is associated with an increase in muscle sympathetic nerve activity and a decrease in cardiac output 4, 3.
• Handgrip strength is negatively correlated with augmentation index, a marker of vascular stiffness, in older adults with metabolic syndrome 6.
• Handgrip asymmetry is positively correlated with peripheral vascular resistance in individuals with metabolic syndrome 6.

Mechanisms

• The increase in systemic vascular resistance during handgrip exercise is mediated by the activation of the sympathetic nervous system and the release of vasoconstrictor substances 5, 3.
• The muscle mechanoreflex plays a primary role in the vasoconstrictor response to handgrip exercise 5.
• The arterial baroreflex also contributes to the regulation of systemic vascular resistance during handgrip exercise 3.