Temperature: use cold water to activate the dive reflex

Submerge your face in cold water or hold a cold pack to your face and hold your breath for 30 seconds.

Why it works

Cold water contact on the face — especially around the eyes and cheeks — activates the mammalian dive reflex, a parasympathetic response that slows the heart rate, sometimes dramatically, within seconds. The dive reflex is not cognitively mediated; it is a hardwired physiological response, which is why it works even when extreme arousal has impaired voluntary regulation. The rapid heart rate reduction is accompanied by a subjective sense of the emotion dropping.

How to do it

1. Fill a bowl with cold water (ideally with ice) or use a cold pack from the freezer.
2. Hold your breath and submerge your face — eyes closed — for 30 seconds, or hold the cold pack against your eyes and cheeks.
3. Do not do this if you have heart conditions, low blood pressure, or cold-induced urticaria.
4. Repeat once or twice if needed — each cycle produces a fresh parasympathetic reset.

Evidence

The mammalian dive reflex is a well-documented physiological phenomenon: facial cold-water contact with breath-holding reduces heart rate via parasympathetic activation. Its application in DBT is a direct translation of this mechanism into a crisis-regulation tool. (mechanistic)

The dive reflex is well established; its efficacy as a standalone emotional regulation intervention specifically has not been RCT-tested apart from the broader DBT package.

Sources

• Panneton (2013), the mammalian diving response, Comprehensive Physiology

Common mistake

Using cool water rather than cold — the effect is weak with mild temperatures; the reflex requires genuinely cold water (near 50°F / 10°C) to produce a strong response.