Peripheral joint cooling increases spinal reflex excitability and serum norepinephrine.

To understand better how reflex excitability is altered with peripheral joint cooling, the authors set out to determine whether a cryotherapy treatment applied to the ankle would increase plasma norepinephrine and result in a heightened H:M ratio. Twenty-two adults were admitted to the hospital on two occasions. During one admission, subjects had ice applied to their ankle and in the other admission a bag of room temperature marbles was applied.