TALK about bad timing.

Andrew Young's heart condition affects two of his races a season but the second this term just happened to arrive on his Winter Olympic finale in Sochi.

Diagnosed aged 15 with tachy­cardia - a faster than normal heart rate - Young completes the vast majority of cross-country skiing races without issue, but yesterday was not one of them.

About to start his second leg of the classic team sprint in Sochi, in which he partnered up with fellow Scot Andrew Musgrave, Young's condition kicked in and forced them to pull out.

Indeed it is the second time it has happened this season, the last occasion during last month's Norwegian Championships, where Musgrave stunned the host nation by winning the individual sprint.

But he is not alone. Multiple Olympic and world champion Marit Bjoergen and skiathlon bronze medalist in Sochi Martin Johnsrud Sundby are just two fellow cross-country skiers to suffer the same condition.

And Young, who looked so impressive in finishing 37th in the 15km classic on Friday, an improvement of 23 places on his previous best placing at his debut Winter Olympics in 2010, had no choice but to shrug and sigh.

"A race, is a race, if it happens, it happens," Young said. "It happens two races a year. Every now and then it happens and you have to stop. Your heart rate shoots up over 200 and it is beating so fast that it doesn't deliver oxygen to the muscles properly and it's hopeless trying to compete.

"The medical advice when I was first diagnosed was that it was more dangerous to have an operation and so it's something you just put up with.

"A lot of athletes have it, Marit and Martin have it, it is a common thing in cross-country skiing. That is how it is. I don't really like using it as an excuse. It's not an excuse, it happens."

Ole Einar Bjoerndalen, meanwhile, finally eclipsed fellow Norwegian Bjorn Daehlie to become the most decorated Winter Olympian with gold in biathlon's new mixed relay. The 40-year-old helped the Norwegian quartet to victory by 33 seconds for a record 13th Winter Olympic medal.

Britons Paula Walker and Rebekah Wilson could only place 12th in the two-woman bobsleigh as Canadian Kaillie Humphries defended her title.