Acute effects of heavy resistance exercise on biomarkers of neuroendocrine-immune regulation in healthy adults: a systematic review.
Level 1 - systematic review of randomized trials
Systematic review of clinical trials examining acute exercise interventions
What was done
A systematic review was conducted across PubMed, Cochrane Controlled Trials Register, Web of Science, and SportDiscus through March 2021. The authors included clinical trials (in English or German) evaluating blood plasma or serum concentrations of selected neuroendocrine-immune biomarkers in healthy adults at rest and up to 60 minutes following an acute bout of heavy resistance exercise. Target biomarkers were adrenaline, noradrenaline, acetylcholine, vasoactive intestinal peptide (VIP), cortisol, growth hormone (GH), calcitonin gene-related peptide (CGRP), substance P, serotonin, brain-derived neurotrophic factor (BDNF), nerve growth factor (NGF), and glia-derived neurotrophic factor (GDNF).
What was found
Thirty-six studies with 58 intervention groups met inclusion criteria. Acute heavy resistance exercise increased immediate post-exercise median levels of adrenaline (median increase: 185%), noradrenaline (median increase: 113%), and growth hormone (median increase: 265%). Cortisol responses were mixed (median increase: 0%). Evidence was insufficient to draw firm conclusions for BDNF and ACTH. For the vast majority of studies, elevated biomarkers returned to baseline within 60 minutes. No studies were identified evaluating acetylcholine, VIP, CGRP, substance P, serotonin, NGF, or GDNF.
Why it matters
This review characterizes the acute neuroendocrine-immune response to resistance exercise, confirming robust but transient surges in catecholamines and growth hormone that resolve within an hour. It also highlights major gaps in the literature regarding exercise effects on neurotrophic factors and neuropeptides.
Limits
The total number of human participants is not reported in the abstract. No meta-analytic effect sizes or confidence intervals are provided beyond median changes. Seven of the 12 targeted biomarkers had zero eligible studies, and BDNF/ACTH data were inconclusive. Exercise configurations and subject characteristics (such as sex) varied, contributing to mixed cortisol findings.
Cited by
- supports The elevation of growth hormone resulting from resistance training is specific to approximately one hour post-workout.