Cardiovascular Responses To Physical And Mental Stress And The Influence Of Post-traumatic Stress Disorder

INTRODUCTION: Patients with post-traumatic stress disorder (PTSD) have an increased risk of developing cardiovascular disease (CVD). The physiological underpinnings contributing to increased CVD risk with PTSD are poorly understood but may involve maladaptive changes in blood pressure regulation during stress. Elevated pressor responses during physical stress, such as exercise, often characterize populations with CVD and may predict future CVD in otherwise healthy adults. Some data suggests aberrant pressor responses during either acute physical or mental stress in PTSD, but evidence is limited, and it is unclear how pressor responses may manifest during combined stimuli. PURPOSE: To investigate pressor responses during acute physical and mental stress, alone and in combination, and to what extent these responses may be exaggerated in patients with PTSD compared to control (CON) subjects. METHODS: In patients with PTSD (n = 2, 34 ± 5 yrs) and CON subjects (n = 2, 33 ± 1 yrs) arterial blood pressure (Finapres) was determined at rest and during static handgrip exercise (SHG, 3 mins, 40% MVC), followed by post-exercise-circulatory-occlusion (PECO, 2 mins). Each condition (rest, SHG, PECO) was also performed with or without Mental arithmetic (MA). RESULTS: Resting mean arterial pressure (MAP) was greater in PTSD vs. CON (91 ± 4 vs. 75 ± 1 mmHg; P = 0.03). The average increase in mean arterial pressure (MAP) during MA was greater in PTSD vs. CON (8 ± 1 vs. 3 ± 1 mmHg; P = 0.03). The increase in MAP at the end of SHG was greater in PTSD vs. CON (44 ± 3 vs. 25 + 3 mmHg; P = 0.01). The increase in MAP during PECO was significantly greater in PTSD vs. CON (31 ± 2 vs. 16 ± 12 mmHg; P = 0.01). MA increased the MAP response during SHG in PTSD (3 ± 1 mmHg; P = 0.02), but not in CON (-2 ± 5 mmHg; P = 0.73). The MAP response during PECO was variably influenced by MA in PTSD and CON (4 ± 3 vs. 3 ± 7 mmHg; P = 0.11). CONCLUSIONS: These preliminary data suggest that pressor responses during acute physical (SHG, PECO) and mental (MA) stress are exaggerated in PTSD. Additionally, it appears that in PTSD, acute mental stress may further augment pressor responses to acute physical stress (SHG + MA). Taken together, these exaggerated pressor responses during acute physical and mental stress may represent a physiological maladaptation that could increase CVD risk in this patient group. Funded in part by grants from the U.S. Veterans Administration (CX002152) and the National Institutes of Health (HL162856)