Body mass index in relation to cardiovascular recovery from psychological stress among trauma-exposed women

Delayed cardiovascular recovery has been associated with greater heart disease risks. However, relative to stress reactivity, cardiovascular recovery has been understudied. Further, few studies have examined associations of recovery with modifiable factors that might inform efforts to enhance recovery. The focus of the present study was whether body mass index (BMI) was associated with recovery following two stress tasks (speech and mental arithmetic). Based on the conceptualization that obesity may lead to impaired post-stress recovery, we also examined whether higher BMI accounted for previously reported associations between elevated PTSD symptoms and delayed recovery. The sample consisted of 50 trauma-exposed civilian women ages 19-49 (M +/- SD = 30 +/- 8). The stress tasks were followed by 15-min post-task rest periods. Cardiovascular recovery was assessed as percentage return to baseline; the recovery measures consisted of heart rate (HR), cardiac output (CO), systolic blood pressure (SBP) and diastolic blood pressure (DBP). PTSD severity was based on structured interview. Higher BMI was associated with significantly less CO recovery from the speech task and less HR recovery from mental arithmetic. Higher BMI was associated with more SBP recovery from the math task, but was not associated with DBP recovery. The indirect effects of BMI in the PTSD/CO recovery relationship based on the Sobel test of mediation were significant. These results partially support the hypotheses that BMI is associated with cardiovascular recovery and that associations of PTSD with recovery may be mediated by BMI.