Mo Farah has revealed for the first time that he was airlifted to hospital last month because doctors feared there was something wrong with his heart after he lost consciousness on his bathroom floor in Park City, Utah.

Farah, who also suffered stomach pains and was kept in hospital for four days, insists he is fit to run in the 5,000m and 10,000m at the European Championships in Zurich – despite doctors still not knowing what caused his “scary” collapse.

“I had a tooth taken out because it was chipped and it got infected,” said Farah, who starts with the 10,000m final onWednesday night. “I was in a bit of pain, but went for a run, and when I came back from a run I literally collapsed on the bathroom floor, completely knocked out.

“I had my phone in my pocket, so when I woke up and became conscious I called Cam [Levins] my training partner, the guy who came third at the Commonwealth Games, and he came round and got me on to my bed. I was in so much pain from my stomach, and so he called an ambulance and it took me to hospital. I then had to be airlifted to the main hospital as they thought something was going on with my heart – it was just crazy.

“I was in hospital for four days and it was scary but these things happen and so I missed quite a lot of running.”

Farah insisted he had not taken the easy option by missing the Commonwealth Games, where he would have faced the exciting Kenyan gold medallist Caleb Ndiku, who has run two of the seven fastest 5,000m times this year.

“After the illness I did a couple of runs and I thought I hadn’t lost very much,” Farah said. “But it takes a lot out of you mentally. I went back to the UK and had a lot of tests and they found nothing, but on the day where I was going to make my decision I was really struggling on a key session. I was nowhere near ready.

“I did one track session and Paula Radcliffe was timing me and she told me I should stop. Someone like Paula telling you to stop, you know there is something wrong and I just wasn’t right – she could see that. It took a lot out of me.

“Later on Paula said I’d taken the easy option, which is not fair as she’d seen me struggle. I was quite disappointed, but if I’m going to turn up I have to be 100%. I’m not going to turn up in my home country and get beat.”

Farah believes he is in “decent shape” after two weeks of hard training in Font Romeu, and says he hopes to replicate his double 5,000m and 10,000m success at the European Championships in Barcelona in 2010 even though he has run only once on the track in 2014. “As an athlete it all started at those Europeans,” he said. “Once I’d won there you’ve got the confidence and then it was about the worlds where I won and came second, but the Europeans is where it all started.”

Farah also admitted that his preparations for the London Marathon in April, where he finished a disappointing eighth in 2:08:21 despite going to Kenya for three months to get ready, had taken more out of him than he had expected.

“A lot of training went into it and I gave it my all,” he said. “I thought I’d have done better, but I gave it a go and that’s what happens sometimes; you’ve just got to say what can I do next time, how can I improve?

“It definitely took more out of me than anything else. In track, you can get ready for 1500m, 5,000m, 10,000m and you can do a lot of speed but with the marathon it’s just a lot of running, a lot more miles and at the end you are pretty tired.”

The British Athletics performance director Neil Black has insisted that his medical staff do not have any worries about Farah’s form – or another occurrence of his terrifying collapse.

“The team of people that support him don’t have any concerns and I think the only people that should be worried are the people who are going to be on the start line with him,” Black said.