Two Branches, One Balance
The autonomic nervous system regulates involuntary functions like heart rate, blood pressure and digestion through two broadly opposing branches: the sympathetic ("fight or flight") and parasympathetic ("rest and digest") systems. Manual therapy appears able to shift the balance between these two branches, at least temporarily.
Massage and a Shift Toward Parasympathetic Dominance
Multiple studies measuring heart rate variability, cortisol and subjective relaxation after massage report findings broadly consistent with increased parasympathetic activity and reduced physiological stress markers (Field, 2014; Diego & Field, 2009).
A More Complex, Biphasic Response to Joint Mobilisation
Spinal mobilisation and manipulation appear to produce a more biphasic autonomic response: an initial brief sympathoexcitatory effect (a short-lived rise in skin conductance and blood pressure) immediately following the technique, which has itself been proposed as part of the mechanism behind the pain relief some clients experience, distinct from the parasympathetic shift more typical of sustained, lighter massage technique (Perry & Green, 2008).
References & Further Reading
- Field T. Massage therapy research review. Complement Ther Clin Pract. 2014;20(4):224-229.
- Diego MA, Field T. Moderate pressure massage elicits a parasympathetic nervous system response. Int J Neurosci. 2009;119(5):630-638.
- Perry J, Green A. An investigation into the effects of a unilaterally applied lumbar mobilisation technique on peripheral sympathetic nervous system activity in the lower limbs. Man Ther. 2008;13(6):492-499.