A cooling vest or ice vest or "precool vest" is a piece of equipment worn to cool a person down. Cooling vests are used by many athletes, industry workers, doctors, working dogs, people with Multiple Sclerosis

Multiple sclerosis

Multiple sclerosis is an inflammatory disease in which the fatty myelin sheaths around the axons of the brain and spinal cord are damaged, leading to demyelination and scarring as well as a broad spectrum of signs and symptoms...

 or Hypohidrotic ectodermal dysplasia

Hypohidrotic ectodermal dysplasia

Hypohidrotic ectodermal dysplasia is one of about 150 types of ectodermal dysplasia in humans...

, and by military pilots and tank crews.

Olympic

Olympic Games

The Olympic Games is a major international event featuring summer and winter sports, in which thousands of athletes participate in a variety of competitions. The Olympic Games have come to be regarded as the world’s foremost sports competition where more than 200 nations participate...

 athletes use the lightweight body cooling vest to pre-cool before events. In advance of the Beijing Olympics in 2008, Nike developed the Nike Precool Vest for Olympic athletes. Intended to be worn for an hour prior to events in the hot and humid conditions in Beijing, Nike reported an expected increase of 21% in an athletes endurance. Other research backs up the improved performance claims. The lightweight Arctic Heat cooling vest was used extensively during the 2004 Athens and 2008 Beijing Olympics.

Vests range in weight from around two to eight pounds, depending on the model. The Nike model is not sold to the public and no information is available. However a number of commercial products of varying weight and cost are available. Some, like the RiteTemp Performance Vest and Hyper Precool Vest, utilize standard cooling gel packs or phase change material, and are designed to hold to the body during movement allowing full normal warm up activity.
Cooling vests can use a number of methods. Some modern vests use the adiabatic expansion of compressed air

Compressed air

Compressed air is air which is kept under a certain pressure, usually greater than that of the atmosphere. In Europe, 10 percent of all electricity used by industry is used to produce compressed air, amounting to 80 terawatt hours consumption per year....

, and can cool a worker for long periods in very hot conditions. Typically, these vests will reduce air temperature by about 25 °F, with a flow rate of no more than about 5 cubic feet per minute on average. Some vests combine neoprene with frozen gels to create a cold compression therapy

Cold compression therapy

Cold Compression Therapy combines two of the principles of R.I.C.E. to reduce pain and swelling from a sports or activity injury to soft tissues and recommended by orthopedic surgeons following surgery...

 vest that drives cold deep into soft tissues to lower core body temperature rapidly. Vests can also use chemical packs, however, most vests are essentially heat sinks that cool a person through conduction

Heat conduction

In heat transfer, conduction is a mode of transfer of energy within and between bodies of matter, due to a temperature gradient. Conduction means collisional and diffusive transfer of kinetic energy of particles of ponderable matter . Conduction takes place in all forms of ponderable matter, viz....

 (although some also dehumidify

Humidity

Humidity is a term for the amount of water vapor in the air, and can refer to any one of several measurements of humidity. Formally, humid air is not "moist air" but a mixture of water vapor and other constituents of air, and humidity is defined in terms of the water content of this mixture,...

 the thin layer air immediately surrounding the body). Some vests use a layered cooling module system to allow for longer term cooling without creating stiffness in the vest.

Cooling vests are similar in function to the Liquid Cooling and Ventilation Garment

Liquid Cooling and Ventilation Garment

A Liquid Cooling Garment is a form-fitting garment that is used to remove body heat from the wearer in environments where evaporative cooling from sweating and open air convection cooling does not work, or the wearer has a biological problem that hinders self-regulation of body temperature.A...

s worn by astronaut

Astronaut

An astronaut or cosmonaut is a person trained by a human spaceflight program to command, pilot, or serve as a crew member of a spacecraft....

s.

Cooling vests and Multiple Sclerosis (MS)

Cooling vests are also used by persons suffering from multiple sclerosis (MS). In multiple sclerosis, nerve fibers become demyelinated which leads to pain and discomfort when temperature is elevated. Nerve fibers may also be remyelinating or in the process of repairing themselves and still be sensitive to elevated temperatures. The cooling vest keeps the patients temperature down reducing the pain symptoms.