Inclusion Criteria:  apparently healthy and free of overt cardiovascular, pulmonary, or metabolic disease for PTSD group, a score of ≥ 33 on PCL-5 checklist for GAD group, a score of ≥ 10 on the GAD-7 self-report scale and < 33 on the PCL-5 checklist for Healthy Control group, a score of ≤ 10 on the GAD-7 self-report scale and < 33 on the PCL-5 checklist  Exclusion Criteria:  taking medications that could influence cardiovascular function current smokers who have recently quit smoking illicit drug use or excessive alcohol consumption pregnant women significant calorie restriction or vitamin/mineral deficiencies limited English proficiency