It would be much easier to just use an ice pack on the neck. A cold shower will increase pulse and likely BP in the beginning. Autonomic nervous system dysfunction is likely due to inflammation in the brain stem thus the value of icing the upper neck.
Mark in Idaho
59 years old, retired due to disability, married 34 years, father of three, grandfather of four, Suffered a serious concussion at 10 years old (1965) stopped most driving after concussion at 46 years old (2001), Post Concussion Syndrome/Multiple Concussion/Impact Syndrome with PTSD, immediate/short term visual and auditory memory problems, slowed processing speed, visual/auditory processing difficulties, insomnia, absence seizures, OCD, 14 concussions since first concussion at 8 years old, Taking paroxetine for 14 years and gabapentin for 12 years. Added L-Tryptophan and stopped paroxetine after 3 months of tapering. I currently take 500 mgs of L-Tryptophan AM, 500 mgs noon, and 500 mgs PM.
As of Nov 15th, Due to high stress issues resulting in PTSD, docs put me on 3 meds. Clonazepam but only for 30 days ) .125 mgs twice daily (Doc presc. .25 mgs 2x daily but half a tablet is good) , citalopram (Celexa), an SSRI , and olanzapine (Zyprexa), an atypical anti-psychotic that usually causes weight gain before bed. I lost over 30 pounds since mid July. It just stopped the weight loss. Took me off the gabapentin. I am feeling better than I have in years.
This great feeling only lasted a month. Back to the same old PCS doldrums.
May 2014, I am off the olanzapine due to a 6 fold price increase. Back on 600 mgs of gabapentin before bed.
I am also taking L-Theanine to help with GABA regulation
"Be Still and Know That I am God" Psalm 46:10