How does hand grip increase Systemic Vascular Resistance (SVR)?

From the Guidelines

Hand grip increases systemic vascular resistance (SVR) through a process called isometric exercise pressor response, which triggers the sympathetic nervous system and causes widespread vasoconstriction in non-exercising tissues throughout the body, resulting in elevated SVR and a moderate increase in blood pressure. This physiological response is supported by the 2019 ACC/AHA guideline on the primary prevention of cardiovascular disease, which highlights the benefits of isometric resistance exercises, such as hand grip, in reducing blood pressure 1. The guideline recommends isometric resistance exercises, including hand grip, as a nonpharmacological intervention for the prevention and treatment of hypertension, with an approximate impact on systolic blood pressure of -5 mm Hg.

The mechanism of hand grip-induced increase in SVR involves the activation of mechanoreceptors and metaboreceptors in the muscles, which detect the contraction and increased metabolic demand, triggering the sympathetic nervous system and releasing norepinephrine, causing vasoconstriction in non-exercising tissues throughout the body 1. Additionally, the hand grip activates central command pathways in the brain that further enhance sympathetic outflow, contributing to the increase in SVR. The combined mechanisms result in elevated SVR, which typically causes a moderate increase in blood pressure while maintaining or slightly increasing cardiac output.

The evidence from the 2019 international consensus on cardiopulmonary resuscitation and emergency cardiovascular care science with treatment recommendations supports the use of physical counterpressure maneuvers, including hand grip, to increase blood pressure in certain clinical situations 1. However, the certainty of evidence is very low, and the results should be interpreted with caution. Nevertheless, the available evidence suggests that hand grip exercises can be a useful nonpharmacological intervention for the prevention and treatment of hypertension, and may also be used in clinical settings to assess cardiovascular reactivity and autonomic function.

Key points to consider:

• Hand grip increases SVR through isometric exercise pressor response
• The mechanism involves the activation of mechanoreceptors and metaboreceptors, triggering the sympathetic nervous system and causing vasoconstriction
• Hand grip exercises can be used as a nonpharmacological intervention for the prevention and treatment of hypertension
• The evidence supports the use of physical counterpressure maneuvers, including hand grip, to increase blood pressure in certain clinical situations, although the certainty of evidence is very low 1.

From the FDA Drug Label

Following parenteral administration of phenylephrine hydrochloride, increases in systolic blood pressure, diastolic blood pressure, mean arterial blood pressure, and total peripheral vascular resistance are observed The FDA drug label does not answer the question.

From the Research

Systemic Vascular Resistance (SVR) and Hand Grip

• There is no direct evidence in the provided studies that explains how hand grip increases systemic vascular resistance (SVR) 2, 3, 4, 5, 6.
• However, it is known that hand grip exercise can increase blood pressure and heart rate, which may be related to changes in SVR.
• Studies have shown that SVR is increased in certain conditions, such as hypertension 4, aortic valve stenosis 5, and chronic cervical spinal cord injury 6.
• In these conditions, increased SVR is often associated with other hemodynamic changes, such as increased blood pressure, decreased cardiac output, and altered arterial stiffness.
• The relationship between hand grip exercise and SVR is not well understood and requires further study to determine the mechanisms involved.

Mechanisms of SVR Increase

• Increased SVR can be caused by a variety of factors, including:
  • Vasoconstriction: narrowing of blood vessels, which increases resistance to blood flow 3, 6.
  • Increased blood pressure: high blood pressure can increase SVR by increasing the pressure on the blood vessels 4, 5.
  • Altered arterial stiffness: changes in the stiffness of blood vessels can affect SVR 5, 6.
• These mechanisms can be influenced by various factors, including exercise, disease states, and medications.

Limitations of Current Evidence

• The provided studies do not directly address the relationship between hand grip exercise and SVR.
• Further research is needed to understand the mechanisms by which hand grip exercise affects SVR and to determine the clinical significance of these changes.