Training in mindfulness is a well-supported therapeutic strategy for pain conditions, though short-term mindfulness training for acute pain is not always effective. To explore the possibility that initial attempts at mindfulness in people without previous training may drain self-regulatory resources, the current study used a student sample (N=63) to test the hypothesis that brief instruction in mindfulness would lead to reduced pain tolerance on a cold pressor task (CPT), compared to more familiar strategies for coping with acute pain. We also investigated whether high heart rate variability (HRV), a physiological indicator of self-regulatory capacity, would predict pain tolerance. Higher HRV predicted greater pain tolerance only in the control group, suggesting that applying unfamiliar mindfulness strategies while attempting to tolerate pain more rapidly sapped self-regulatory strength.