In this file photo taken on March 2, 2013, a woman swims in icy, cold waters in Tallinn, Estonia. (RAIGO PAJULA / AFP)

TALLINN - Over 500 swimmers swam in the near-freezing waters of Tallinn port in Estonia on Friday, taking part in a giant winter swimming relay in a country where the sport has been a popular way to counter the tedium of coronavirus restrictions.

The 505 participants each swam the course of 25 metres marked out in a former submarine dockyard, taking 4 hours and 50 minutes to do so.

The swimmers, many attired with funny hats, ranged from a 9-year old boy to an 83-year old woman, and included a pregnant woman who joked her effort should be counted for two

The swimmers, many attired with funny hats, ranged from a 9-year old boy to an 83-year old woman, and included a pregnant woman who joked her effort should be counted for two.

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“It’s actually a smart thing to do at this moment”, Roy Vissers, one of the swimmers, said after emerging from the 4 Celsius waters into the below-freezing air.

He believed the sport provided good protection against COVID-19.

“When you’re doing this, your body produces extra white blood cells. So, if a virus comes in, there are more white blood cells to attack it and kill it,” he told Reuters.

Dozens of spectators cheered along the course, many from hot tubs and mobile saunas set up along the side.

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Aivar Tugedam, a winter swimming enthusiast who organized the event, said he had seen the sport grow in popularity since Estonia first went into a coronavirus lockdown in spring.

“Let’s say from spring until now, I would say the count of the winter swimmers have tripled in Estonia. It’s gone wild and really popular”, he said.