Lower vascular conductance responses to handgrip exercise are improved following acute antioxidant supplementation in young individuals with post-traumatic stress disorder

Abstract

Young individuals with post-traumatic stress disorder (PTSD) display peripheral vascular and autonomic nervous system dysfunction, two factors potentially stemming from a redox imbalance. It is currently unclear if these aforementioned factors, observed at rest, alter peripheral haemodynamic responses to exercise in this population. This study examined haemodynamic responses to handgrip exercise in young individuals with PTSD following acute antioxidant (AO) supplementation. Thirteen young individuals with PTSD (age 23 ± 3 years), and 13 age- and sex-matched controls (CTRL) participated in the study. Exercise-induced changes to arm blood flow (BF), mean arterial pressure (MAP) and vascular conductance (VC) were evaluated across two workloads of rhythmic handgrip exercise (3 and 6 kg). The PTSD group participated in two visits, consuming either a placebo (PL) or AO prior to their visits. The PTSD group demonstrated significantly lower VC (P = 0.04) across all exercise workloads (vs. CTRL), which was significantly improved following AO supplementation. In the PTSD group, AO supplementation improved VC in participants possessing the lowest VC responses to handgrip exercise, with AO supplementation significantly improving VC responses (3 and 6 kg: P < 0.01) by blunting elevated exercise-induced MAP responses (3 kg: P = 0.01; 6 kg: P < 0.01). Lower VC responses during handgrip exercise were improved following AO supplementation in young individuals with PTSD. AO supplementation was associated with a blunting of exercise-induced MAP responses in individuals with PTSD displaying elevated MAP responses. This study revealed that young individuals with PTSD exhibit abnormal, peripherally mediated exercise responses that may be linked to a redox imbalance.

Keywords: antioxidant; autonomic nervous system; mental health; vascular function.

FIGURE 1

Change in brachial artery (BA) blood flow (BA blood flow: a; ΔBA blood flow: b), mean arterial pressure (MAP: c; ΔMAP: d), and vascular conductance (VC: e; ΔVC: f) in response to HG exercise at 3 and 6 kg in young healthy controls (CTRL) and individuals with posttraumatic stress disorder after acute consumption of placebo (PTSD+PL) and antioxidants (PTSD+AO). Data are represented as means ± standard deviation. Data were evaluated with two‐way repeated measures analysis of variance. #P < 0.05 versus control group at the same workload.

FIGURE 2

Change in vascular conductance (ΔVC; a, b), mean arterial pressure (ΔMAP; c, d), and brachial artery blood flow (ΔBF; e, f) in response to 3 and 6 kg handgrip workloads during the PL and AO visit in young individuals with PTSD separated by low (3 kg: ≤1.0; 6 kg: ≤1.5 mL min⁻¹ mmHg⁻¹; n = 7) or high (3 kg: >1.0; 6 kg: >1.5 mL min⁻¹ mmHg⁻¹; n = 6) VC responses to handgrip exercise. Data are represented as means ± standard deviation. Data were evaluated with two‐way repeated measures analysis of variance. *Significant difference (P < 0.05) between PL and AO conditions in the low VC group.