Manchester United are using cooling jackets in a bid to help their players deal with the heat during their Premier League Super Series campaign in the United States.

Cooling jackets have been around in various forms as early as the 1950s and 60s, first used by the military and have since been used in a range of sports including Formula 1, cycling, tennis and rowing.

They are designed to reduce an athlete's core and skin temperature, with studies showing it can lead to an improvement in endurance, performance and limit the risks of heat stroke and heat exhaustion.

The type currently used by United are from a range by kit manufacturers Adidas that were launched earlier this year.

Those cooling jackets are being worn by players following warm-ups and at half-time of their three matches in the United States.

Players at the 2025 Club World Cup this summer experienced extreme heat in a number of matches. Multiple cooling breaks were taken, as well as some stadiums installing large mist fans on the sidelines.

Borussia Dortmund's substitutes also spent the first half of their group stage match against Mamelodi Sundowns sat in the changing room to avoid the heat.

How are cooling jackets used and do they actually work?

The earliest models of cooling jackets used by the army required a power supply to circulate cold water around the body, but technological advancements since then mean this is no longer the case.

When Adidas released their Climacool System technology earlier this year, it consisted of an insulated jacket that goes over the top of a cooling vest.

"For the same exercise intensity in a hot compared to a cooler condition, the heart rate's higher, the body temperature's higher. That can lead to things like heat stroke, or even maybe even worse, heat exhaustion," said Dr Chris Tyler, a reader in environmental physiology from the University of Roehampton.

"What the vest will claim to do is reduce all of that. So they will lower the body temperature, lower the heart rate and lower the strain."

The use of the vest is key into its effectiveness. There is a major difference between how someone's body feels to them and their actual body temperature.

They need to be worn for a sustained period and cover as much of the body as possible.

This allows more time for the body to effectively cool down quicker, reducing the risks attached to being too hot and also helping athletes to run quicker and for longer with less strain.

A difference maker for the 2026 World Cup?

"The drivers will be sitting, so they won't be doing as much activity as if say you were running, but they're going to sitting on an engine, they're going to be sitting on a hot track.

"I have my doubts that they're going to be able to extract enough heat to actually lower the strain of the drivers, but they're certainly going to make the drivers feel a bit cooler.

"It also provides a nice platform for all of their companies and sponsors to have another place to have their badge which is something that the Formula One teams have suddenly cottoned onto."