The vest is designed to cool the body’s core temperature.
A 1960s mini dress and medical packaging were the inspiration when it came to redesigning Nike’s original PreCool Vest. First introduced in Athens, Nike wanted it to be lighter, more flexible, better fitting and refillable—a tall order for a piece of equipment athletes have been praising since Athens.
The vest is designed to cool the body’s core temperature. Since 25% of our body's total energy goes into moving muscle and 75% into regulating heat, reducing an athlete’s core temperature before the marathon or a field hockey match means more energy for the competition itself. Indeed, with core cooling, athletes can often last 21% longer. Given Beijing’s hot and humid conditions, the PreCool Vest is a key piece of equipment that can help provide the advantage an athlete needs.
In improving the vest, Eddy Harber and Irena Ilcheva of Nike’s AIT or Advanced Innovation Team focused on apparel development turned to high fashion, specifically a dress made of tiny metal discs. Like chain mail, it clings to its wearer. It was thought the geometry—smaller discs to hug the body’s curves and larger discs over flatter planes like the back and stomach—would work for the vest. A grid of triangles was used, smaller on the shoulders and larger down the spine, to maximize skin contact. The closer the fit, the less ice needed to cool the body, and the lighter the vest became.
Each triangle is made of two layers to keep it cool. The inner one is filled with water, which is frozen, while the outer layer insulates like a thermos. Coated with aluminum, the triangles also reflect radiant heat working like the coating on mirrored sunglasses. That coating and insulated layer also mean less ice. Even more weight was reduced by making the PreCool Vest refillable. Instead of having to travel with a seven-pound vest pre-filled with liquid, the design team created sealed compartments that athletes fill and freeze before competition. The product inspiration came from medical packaging used to transport blood and other fluids. Medical products have strict compliance issues—they must be absolutely leak proof. “As we were thinking ‘How do we make this?’” Harber explains, “We looked to the medical packaging and how it’s made with one big weld. That was a perfect solution.”
Nike partnered with a medical supply company to make the actual vest. Each one will be individually tested, and though the engineering that goes into the vests is high tech, they’re being made from sustainable materials. Recycled Nike Air soles are used and the felt carry case, which helps keep the vest cold, comes from recycled men’s suits.