Multiple soldiers fainted at rehearsals for King Charles' birthday parade during a heat wave. Photos show it's been an issue for decades.

• Several soldiers fainted during rehearsals for King Charles' birthday parade on Saturday.
• The annual event is held in June, and many guards have fainted over the years due to the heat.

Every summer, Buckingham Palace hosts Trooping the Colour, a military parade held in celebration of the monarch's birthday.

Ahead of King Charles' first parade as monarch on June 17, a rehearsal parade known as the Colonial Review was held by Prince William on Saturday.

As the Associated Press reported, at least three soldiers fainted during the ceremony, likely due to the hot weather conditions in London; the temperature in the UK capital on Saturday was expected to hit 30 C (86 F), and data from Accuweather shows it reached 28 C (84 F).

But this isn't the first time royal guards have fainted at royal events — it's happened on a number of occasions before, at least since the 1950s. Take a look.

Several soldiers fainted during rehearsals for King Charles' birthday parade over the weekend.

A soldier faints during Trooping the Colour rehearsals in London on June 10, 2023.      ADRIAN DENNIS/AFP via Getty Images

Trooping the Colour has been a royal tradition for more than 260 years, according to the official royal website. One of the first images of a soldier fainting during the ceremony was taken in 1957.

A guardsman faints during the Trooping of the Colour ceremony in London to celebrate the official birthday of Queen Elizabeth II on June 19, 1957.      Keystone/Getty Images

Source: Royal.uk

The ceremony is held in the summertime and soldiers traditionally wear a black bearskin hat and a military jacket. In 1963, a soldier fainted during rehearsals.

First-aid attendants help a Guardsman after he fainted during a rehearsal for the Trooping of the Colour in London on June 1, 1963.      Douglas Miller/Keystone/Getty Images

Read more: A royal guard shares 5 hidden details on his iconic blood-red uniform and the meaning behind them

In this photo taken in 1973, a soldier can be seen on the ground as the others around him carried on with rehearsals.

A soldier faints during Trooping the Colour rehearsals in London on May 26, 1973.      Evening Standard/Hulton Archive/Getty Images

A soldier was carried away on a stretcher after he fainted during the ceremony in 1974.

A soldier of the Scots Guard is stretchered off the parade ground during the Trooping the Colour ceremony in London on June 17, 1974.      Daily Mirror/Mirrorpix/Mirrorpix via Getty Images

Decades later, in 2000, one soldier was carried away for medical attention after fainting while those around him stood to attention.

A Coldstream Guardsman is carried off after fainting during the Trooping the Colour ceremony in London on June 17, 2000.      Michael Stephens - PA Images/PA Images via Getty Images

A member of the Scots Guard fainted during the Colonel's Review — the same ceremony soldiers were rehearsing for on Saturday — in 2010.

A member of the Scots Guards faints during the Colonel's Review in London in June 2010.      Dominic Lipinski/PA Images via Getty Images

Another guard was carried on a stretcher after fainting during the Trooping the Colour parade in 2017.

A Guardsman lies on a stretcher after fainting during the annual Trooping The Colour parade in London on June 17, 2017.      Jack Taylor/Getty Images

With hotter temperatures becoming more common, an army spokesperson told Insider that medics are often on standby at royal ceremonies.

The Royal Family watching the flypast at Trooping the Colour in June 2022.      Chris Jackson/Getty

Heat waves dominated last summer and are becoming increasingly common due to climate change, as Insider previously reported.

An army spokesperson told Insider that while they can't comment on the individual cases of fainting over the weekend, those affected have received treatment.

They added that medics are often prepared for minor injuries, including fainting, and that soldiers also receive training to be able to withstand long periods of standing and marching.

Buckingham Palace did not respond to Insider's request for comment.