It was on Sunday that the incident occurred when Monika was out for a swim.

"I'm training for Vansbrosimmet and was swimming past Gingerbread Cape when it happened. I felt that I was getting suddenly strained and then my chest started to wham and I got harder and harder to breathe.

Several people remained on land and watched as Monika ended up in distress – but not Elton, who swam out and helped her to shore.

The diagnosis of SIPE – like drowning from within

After that, Monika was taken to hospital.

"I was examined with ultrasound and X-rays and was diagnosed with something called SIPE or swimming-induced pulmonary edema.

The condition is something that doctor and researcher Maria Hårdstedt has looked into. About 40 to 50 people are affected each year during Vansbroswimmingen.

"You could say it's like drowning from within. The pressure increases in the small vessels, which means that fluid is pushed out into the pulmonary vesicles and you find it difficult to breathe. The important thing is to get to land quickly," says Maria Hårdstedt at the Centre for Clinical Research in Region Dalarna.

No deaths associated with swimming

According to her, there are no recorded deaths associated with swimming that can be linked to SIPE. However, when diving.

"SIPE is unusual. It's sad if we scare people away from swimming in open water. On the other hand, you should think about safety. Do not swim in open water alone far from land.

The next day, Monika posted a call on social media to get hold of the lifeguard and thank him again. SVT meets the two at the place where the drama took place.

In the clip: How the heroic effort happened – hear Elton tell the story.