Former Celtic manager Ronny Deila has revealed the true extent of the stress he was under at Parkhead.

The Norwegian announced his decision to step aside at the end of last season after a difficult campaign in which he led Celtic to a fifth successive title but failed to make any kind of European impact.

A defeat in the Scottish Cup to Rangers was the catalyst for Deila's departure and he told Norway's NRK television channel just how difficult it got as he felt his mental health suffer.

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“I could have a stressful thought like: ‘We have to win this weekend.’" explained Deila. "Then I would be soaked in sweat, my heart would be pounding and head aching. I could wake up at four in the morning and couldn’t fall asleep again.

“I almost got social anxiety, I was more passive. It took my freedom from me, the freedom to be myself. Then it became a question of values: can you do this for the rest of your life?”

However, Deila has no regrets over his decision to take the job when he was offered it when he followed in Neil Lennon's footsteps.

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"I would take the challenge at Celtic a thousand times again,” he said. “With hindsight I see that I didn’t have a chance to understand how big a a club Celtic is.

"We have 10 million fans, plays 60 games a season. You have to win all the time. One loss leads to unrest, two are a disaster and three, you are fired. It’s almost at that level.

“You do not get better by playing chess with your daughter for eight years. She gets better, not you. You have to go for something that is unsafe, where you do not know what’s going to happen.

“That’s the way you handle the different experiences that determine whether you are improving or not.”