2 - (SYM 121) Neurobiological, Motivational and Psychological Benefits of Exercise in Chronic Pain and PTSD: a Proof -of- concept Study

Resting levels of the equipotent GABAergic neurosteroids allopregnanolone and pregnanolone (ALLO + PA), which have anti-stress and anti-nociceptive benefits, are driven down by exposure to chronic or extreme stress and are inversely related to PTSD severity in men and women. Our preliminary work demonstrated large increases in plasma ALLO+PA levels in response to acute, intense exercise testing. In this study, we assessed the effects of 12 weeks of (3 x 30-minute sessions/week) individualized, moderate-to-vigorous intensity, aerobic exercise training on levels of ALLO+PA. We also explored the relationship of ALLO+PA to exercise-based motivational factors (i.e., a composite measure of intrinsic motivation) and the relationship of intrinsic motivation for exercise to clinical symptoms (i.e., PTSD and depression severity) in sedentary, medication free civilians and Veterans with chronic pain (CP) and PTSD (N=14 completers; age 39.6 ± 9.8 years; 50% female; 60% Veterans).

A.    ALLO+PA levels: There was a two-fold increase in resting plasma ALLO+PA levels from pre-training [2203.4 (2351.6) pg/mL)] to post-training [4608.2 (5153.3) pg/mL]; d’=-.42

B.    ALLO+PA in Association with Intrinsic Motivation for Exercise: Before exercise training, ALLO+PA was not associated with intrinsic motivation for exercise. After 12 weeks of training, ALLO+PA was strongly and positively associated with intrinsic motivation for exercise  (r=.87*).

C.    Intrinsic Motivation for Exercise in Association with Clinical Symptoms:  Before exercise training, intrinsic motivation for exercise was weakly associated with PTSD and depression severity. After 12 weeks of training, intrinsic motivation for exercise was strongly and negatively associated with these symptoms (rPTSD= -.65*; rdepression= -.83*).

A 3-month, individualized, aerobic exercise training program was associated with increases in resting plasma ALLO+PA levels. Post- but not pre-training Allo+PA levels were positively associated with intrinsic motivation for exercise, which in turn was negatively associated with post-training PTSD and depression symptoms. Larger controlled studies are needed to replicate and generalize these findings to individuals with less stringent eligibility critera. Such findings may inform development of additional behavioral treatment options for comorbid CP and PTSD with the potential for integration with cognitive therapies for CP and/or PTSD.