The Ice Protocol: How External Cooling Helps You Race in the Heat

As temperatures climb, drinking alone cannot always keep up with a rising core temperature. Knowing your sweat rate and replacing fluid and sodium is the foundation of summer performance, and external cooling builds on it.

Drinking has a ceiling. Your gut can absorb only so much fluid each hour. On a hot race day you can reach a point where you cannot drink your way out of the heat.

What heat does to your body. To release heat, your body sends more blood to your skin, which competes with your working muscles and digestion for blood flow. Combined with the plasma volume you lose through sweat, this is a main driver of cardiovascular drift, where your heart rate climbs just to hold the same pace or power. As core temperature rises, effort feels harder and your brain reduces the drive to your muscles, so you slow down.

The Ice Protocol. External cooling lowers skin temperature and makes the heat feel more manageable. Research shows that cooling during exercise in the heat can improve performance, and cooling the head, face and neck works largely by changing how hot you feel, which supports your pacing. The three target areas are the back of the neck, the inside of the wrists and the groin. These are places where large blood vessels sit close to the skin, and cooling them is also standard first aid practice for heat illness.

Putting it into practice. At hot aid stations and transitions, do not just fill your flasks. Stuff ice into a bandana and tie it around your neck, drop ice cubes into your arm sleeves so they rest against your wrists, put a handful under your hat, and hold ice against your groin while you stop.

Manage heat externally, keep your fluid and sodium plan on track, and you give yourself the best chance of carrying your pace to the finish line.