So you fell asleep during your massage. Great! That's likely what your body needed, according to Brogan, LMT at PRESS Williamsburg.
Massages elicits the parasympathetic nervous system response and creates a return to "rest and digest." Activating this system essentially undoes the effects created when the mind and body are in fight-or-flight mode. Additionally, massage can lower stress hormones while increasing dopamine and endorphin levels that help improve mood and decrease pain.
In other words, if massage makes you sleepy, it's because the body is literally resting and revitalizing itself. Brogan explains more in this short clip.
More research is supporting this claim. In a 2018 single-blind randomized controlled trial of 44 healthy women, rhythmical massage therapy was effective in improving autonomic nervous system function in both the short- and long-term (Seifert et al., 2018).
A newer study published in Scientific Reports in 2020 measured both the physiological and psychological effects of massage. They measured heart rate variability, the time in between heartbeats which increases in length and variability when the body is relaxed. Researchers found that participants who received a massage had a significantly higher heart rate variability and reported feeling less stressed and more relaxed (Meier et al., 2020).
Additionally, head and neck massage might be particularly effective for inducing sleep. Massaging this area can stimulate the vagus nerve, the largest and most complex cranial nerve in the body. Approximately 75% of parasympathetic nerve fibers are located here!
Next time you're having trouble sleeping, try scheduling a massage before your bedtime.