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 (V̇O₂max) relative to controls; however, whether V̇O₂max is blunted in women with PTSD remains unknown. Furthermore, it is unclear what determinant(s) (i.e., central and/or peripheral) of V̇O₂max are impacted by PTSD. Therefore, we evaluated the central (i.e., cardiac output; Q̇_c) and peripheral (i.e., arterio-venous oxygen difference) determinants of V̇O₂max in women with PTSD; hypothesizing that V̇O₂max would be lower in women with PTSD compared to women without PTSD (Controls), primarily due to smaller increases in stroke volume (SV), and therefore Q̇_c. Oxygen uptake (V̇O₂), heart rate (HR), Q̇_c, SV, and arterio-venous oxygen difference were measured in women with PTSD (n=15; 43[11] years, mean [SD]) and Controls ( n=17; 45[11] years) at rest, and during an incremental maximal treadmill exercise test, and the Q̇_c/V̇O₂ slope was calculated. V̇O₂max was not different between women with and without PTSD (24.3[5.6] vs. 26.4[5.0] mL∙kg^-1∙min^-1; P=0.265). However, women with PTSD had higher Q̇_c ( P=0.002) (primarily due to greater SV ( P=0.069), not HR ( P=0.285)), and lower arterio-venous oxygen difference ( P=0.002) throughout exercise compared to Controls. Furthermore, the Q̇_c/V̇O₂ slope was steeper in women with PTSD relative to Controls (6.6[1.4] vs. 5.7[1.0] AU; P=0.033). Following exercise, women with PTSD exhibited slower HR recovery following exercise than Controls ( P=0.046). Thus, despite attenuated peripheral oxygen extraction, V̇O₂max is not reduced in women with PTSD, likely due to larger increases in Q̇_c.