This is a collaborative study between the Institute for Exercise and Environmental Medicine (IEEM; Texas Health Resources/University of Texas Southwestern medical Center) and VA North Texas Healthcare System (VANTHCS). The overall study was conceptualized and initiated by Dr. Qi Fu and her research team at the IEEM. IEEM researchers will be responsible for recruitment of non-veteran women without a diagnosis of PTSD, physiological assessments, and the lifestyle modification intervention. VANTHCS researchers will be responsible for recruitment of women veterans with PTSD and psychological assessments. The procedures taking place at VANTHCS (recruitment of women Veterans with PTSD and psychological assessments) will fall under a separate study (overseen by VANTCHS IRB and RDC) and will not include the procedures and intervention that will take place at the IEEM (which will be overseen by a separate IRB). Data will be shared between the sites per data sharing agreement. This clinical trials entry reflects the VANTHCS study. Outcome measures gathered by the IEEM research team are included in this entry due to the data sharing agreement.