Attenuated peripheral oxygen extraction and greater cardiac output in women with posttraumatic stress disorder during exercise

Posttraumatic stress disorder (PTSD) is associated with an increased risk of developing cardiovascular disease, especially in women. Evidence indicates that men with PTSD exhibit lower maximal oxygen uptake (V^_ O_2max) relative to controls; however, whether V^_ O_2max is blunted in women with PTSD remains unknown. Furthermore, it is unclear what determinants (i.e., central and/ or peripheral) of V^_ O_2max are impacted by PTSD. Therefore, we evaluated the central (i.e., cardiac output; Q^__c) and peripheral (i.e., arteriovenous oxygen difference) determinants of V^_ O_2max in women with PTSD; hypothesizing that V^_ O_2max would be lower in women with PTSD compared with women without PTSD (controls), primarily due to smaller increases in stroke volume (SV), and therefore Q^__c. Oxygen uptake (V^_ O₂), heart rate (HR), Q^__c, SV, and arteriovenous oxygen difference were measured in women with PTSD (n ¼ 14; mean [SD]: 43 [11] yr,) and controls (n ¼ 17; 45 [11] yr) at rest, and during an incremental maximal treadmill exercise test, and the Q^__c/V^_ O₂ slope was calculated. V^_ O_2max was not different between women with and without PTSD (24.3 [5.6] vs. 26.4 [5.0] mL/kg/min; P ¼ 0.265). However, women with PTSD had higher Q^__c [P ¼ 0.002; primarily due to greater SV (P ¼ 0.069), not HR (P ¼ 0.285)], and lower arteriovenous oxygen difference (P ¼ 0.002) throughout exercise compared with controls. Furthermore, the Q^__c/V^_ O₂ slope was steeper in women with PTSD relative to controls (6.6 [1.4] vs. 5.7 [1.0] AU; P ¼ 0.033). Following maximal exercise, women with PTSD exhibited slower HR recovery than controls (P ¼ 0.046). Thus, despite attenuated peripheral oxygen extraction, V^_ O_2max is not reduced in women with PTSD, likely due to larger increases in Q^__c. NEW & NOTEWORTHY The current study indicates that V^_ O_2max is not different between women with and without PTSD; however, women with PTSD exhibit blunted peripheral extraction of oxygen, thus requiring an increase in Q^__c to meet metabolic demand during exercise. Furthermore, following exercise, women with PTSD demonstrate impaired autonomic cardiovascular control relative to sedentary controls. We interpret these data to indicate that women with PTSD demonstrate aberrant cardiovascular responses during and immediately following fatiguing exercise.