Arm and Intensity-Matched Leg Exercise Induce Similar Inflammatory Responses

Area of Science:

• Exercise physiology
• Immunology

Background:

• Active muscle mass influences exercise-induced inflammation, impacting chronic disease risk.
• Individuals with injuries or disabilities may be restricted to upper body exercise, necessitating understanding of its inflammatory effects.

Purpose of the Study:

• To compare the acute inflammatory responses between arm exercise and intensity-matched leg exercise (cycling).

Main Methods:

• Twelve males underwent 45-min constant load trials: arm cranking (60% peak oxygen uptake arm), moderate cycling (60% peak oxygen uptake cycling), and easy cycling (60% peak oxygen uptake arm).
• Cytokine, adrenaline, and monocyte subset analyses were performed pre- and post-exercise (up to 4 hours).

Main Results:

• Plasma IL-6 and IL-1ra increased in all trials, with higher concentrations after arm exercise and moderate cycling compared to easy cycling.
• Arm exercise and moderate cycling induced greater increases in monocyte numbers and the classical monocyte subset post-exercise than easy cycling.
• Postexercise adrenaline levels were lowest following easy cycling.

Conclusions:

• Relative exercise intensity, rather than the mode of exercise (arm vs. leg), is the primary determinant of the acute inflammatory response.
• Findings are highly relevant for individuals with physical limitations or disabilities who rely on upper body exercise.