Start slow (warmer then colder)—as cold shock (冷休克) is possible; just as with lifting weights or other forms of exercise.

The water temperature should be uncomfortably cold yet safe to stay in for a few minutes. The colder the stimulus (water immersion, shower, etc.), the shorter amount of time you need to expose yourself to the cold.

The “Counting Walls” Approach

• The Concept of Walls
  • “Walls” are the mental barriers or resistance you feel (e.g., “Get me out of here”).
  • They are caused by adrenaline pulses. Overcoming them triggers the adaptive response.
• Top-Down Control (Resilience & Grit)
  • Staying in the cold despite the urge to exit exerts ‘top-down control’ from the prefrontal cortex over reflexive brain centers.
  • This builds resilience and grit.
• The Method
  • Challenge yourself by counting walls.
  • Set a goal of “walls” to traverse (e.g., 3–5 walls) per session.
• Progression Levels
  • Level 1: Stay completely still.
    • Keeps a thermal layer around your body (insulation).
  • Level 2: Move your limbs.
    • Breaks the thermal layer; makes it feel much colder.

The Søeberg Principle

Based on deliberate cold researcher Dr. Susanna Søeberg, the principle is: To enhance the metabolic effects of cold, force your body to reheat on its own. (a.k.a “End With Cold”).

• Shivering is the key component.

  If you want to use deliberate cold exposure to increase metabolism, you should get to the point where you shiver in the cold exposure or immediately after.

• Method: Natural Reheating

  • Let your body reheat naturally by drying yourself out in the air for about 1–3 minutes.
  • Avoid:
    • Toweling off.
    • Standing under a warm shower.
    • Huddling or crossing your arms while in the cold or after getting out.