Growth hormone levels after flywheel ergometer exercise: correlation with independent variables

Area of Science:

• Exercise Physiology
• Spaceflight Physiology

Background:

• In-flight muscle mass and strength loss are linked to reduced growth hormone (GH) levels.
• Exercise interventions may help predict and mitigate these losses by influencing GH concentrations.

Purpose of the Study:

• To assess if exercise variables predict growth hormone (GH) variance during flywheel ergometer (FE) workouts.
• To determine the impact of contractile mode and workload on post-exercise GH levels.

Main Methods:

• Seventeen subjects performed randomized FE workouts.
• Variables measured included body mass, blood lactate (BLa-), peak angular velocity (PAV), average power (AP), and total work (TW).
• GH concentrations were measured pre-exercise and at 1 and 30 minutes post-exercise.

Main Results:

• A multivariate regression model predicted deltaGH (change in GH) using body mass, post-exercise BLa-, deltaBLa- (change in BLa-), PAV, TW, and AP.
• Univariate correlations identified body mass, deltaBLa-, and TW as the strongest predictors of deltaGH variance.

Conclusions:

• Body mass, changes in blood lactate, and total work are key predictors of GH response to FE exercise.
• Further research is needed to identify additional variables explaining GH variance in FE workouts.