Neuroendocrine response following a thoracic spinal manipulation in healthy men

Abstract

STUDY DESIGN: Controlled laboratory study. BACKGROUND: Spinal manipulation (SM) can trigger a cascade of responses involving multiple systems, including the sympathetic nervous system and the endocrine system, specifically, the hypothalamic-pituitary axis. However, no manual therapy study has investigated the neuroendocrine response to SM (ie, sympathetic nervous system-hypothalamic-pituitary axis) in the same trial. OBJECTIVE: To determine short-Term changes in sympathetic nervous system activity, heart rate variability, and endocrine activity (cortisol, testosterone, and testosterone-cortisol [T/C] ratio) following a thoracic SM. METHODS: Twenty-four healthy men aged between 18 and 45 years were randomized into 2 groups: Thoracic SM (n = 12) and sham (n = 12). Outcome measures were salivary cortisol (micrograms per deciliter), salivary testosterone (picograms per milliliter), T/C ratio, heart rate variability, and changes in oxyhemoglobin concentration of the right calf muscle (micromoles per liter). Measurements were done before and at 5 minutes, 30 minutes, and approximately 6 hours after intervention. RESULTS: A statistically significant group-by-Time interaction was noted for T/C ratio (P