Good for you MotownJohnny! I also ride for miles on my bike. I have balance issues due to an undiagnosed autoimmune disease, in addition to the PTSD. I have ataxia and jerky tic-like abnormal body movements. I use exercise to bring down the stress, usually a long bike ride. A 20 to 30 mile bike ride calms the anxiety and lets me walk in a straight line, without the tics or balance problems.