A woman has abandoned her attempt to become the first person to swim the world's seven toughest ocean channels in a year.
Beth French, from Wellington, Somerset, who used to use a wheelchair after developing ME, completed half of the Ocean's Seven challenge.
Only six people around the world have ever completed the challenge in their lifetime.
The single mother said she could not carry on and care for her autistic son.
Ms French, 39, was in Japan attempting the latest leg of the global challenge, which involves some of the world's toughest swimming in the following places:
- The North Channel (between Ireland and Scotland)
- The Cook Strait in New Zealand
- The Molokai Channel in Hawaii
- The English Channel
- The Catalina Channel in California
- The Tsugaru Strait in Japan
- The Strait of Gibraltar
She said on her Facebook page: "Juggling life as a self-employed lone parent is tough.
"Swimming offered me balance and adventure, which I craved.
"But since the Molokai Channel, I have had a different perspective. I have not been able to sleep solo for eight months and it is getting worse."
She said her eight-year-old son's anxiety peaked during her swims and had been "getting more violent and tempestuous".
"The fallout is that he is feeling awful about himself as he is not able to control his stress levels and gets terrified about hurting people because of it," she added.
"I absolutely believe that I could achieve Ocean's Seven in a year. But the cost to my son is too great."
Ms French was struck with glandular fever at the age of 10 and diagnosed with ME, also known as Chronic Fatigue Syndrome, at 17, when she was forced to use a wheelchair.
After swimming the English Channel in 2012, she went on to complete a 24-hour swim in the Molokai Channel in Hawaii in December 2012.