British Olympic rowing champion Tom James has revealed he missed training on Wednesday after experiencing a recurrence of the heart condition he developed during the winter.

James, who has been suffering from atrial fibrillation, woke with an elevated heart rate and sat out the session at Eton Dorney, with reserve Cameron Nichol taking his place in the men's four.

GB Rowing performance director David Tanner admitted James' condition would have been a concern had the 28-year-old been forced to miss training on Thursday. However, the Wrexham-born rower has returned to the water, allaying any fears over his participation in the Olympic Games.

James said: "We had a long trip around the athletes' village and it was quite a sunny day and I just had a bit of a raised heart rate the next morning. I took precautions so I just stayed in and let the others go for a row.

"The heart rate was back down this morning. I'm feeling fine. We take our morning monitoring every morning and it was just a bit elevated. I felt a little bit tired from the day before. We are coming into the Olympics, you just make sure you are extra careful.

"There's no harm in taking a bit of time out and being extra cautious."

James was diagnosed with atrial fibrillation in January after contracting a bug over Christmas. Even light exercise would lead to his heart rate "going crazy" but the condition is controlled by medication and closely monitored by GB Rowing doctor Anne Redgrave.

"It's not uncommon. In Silvretta (on a recent training camp), I had a day off. Sometimes your training day is pretty hard and you have to take precautions," James said. "Sometimes you have to take a day off so you can recover properly, rather than get ill and take two or three days off. It's no drama."

And Tanner added: "We just decided to give him a rest. It is nothing sinister. We are very careful with our guys. He wasn't feeling absolutely tops but he is feeling tops today.

"We have a policy of 'any question, we put the sub in'. There is no issue with Tom. There was no injury, he just wasn't feeling tops. It would have been a concern if it had carried on today, of course. We wouldn't have him in the boat if he wasn't good."