Livingston manager Gary Holt admits he had “a wee fright” after being taken on hospital when his blood levels rose to 3,000 times what they should have been.
The 46-year-old ended up with rhabdomyolysis, where skeletal muscle breaks down rapidly, after over-exerting himself in a gym session.
But he will be back in the dugout after a two-week break when Livingston visit Rangers on Saturday.
“I’m thankfully on the mend,” Holt told BBC Scotland.
“I’ll probably be back in the gym pretty soon but not just as hard, but when you go to the toilet and your urine’s like red wine, it kind of gives you a wee fright.”
Holt, who was taken to hospital two days after his Monday gym session, admits he had not realised the severity of his condition because, apart from sore arms, “everything was internal”.
“I was badgering them to let me out until a specialist came on the Friday and told me in no uncertain terms and the reason why and how serious it was,” he said.
“My blood levels were through the roof. I was 145,000 and a normal person’s 50. I was like that: ‘50,000’ and they said, no, 50.”
Rhabdomyolysis symptoms include muscle pains, weakness, vomiting and confusion, while some of the muscle breakdown products, such as the protein myoglobin, may lead to kidney failure.
“It was kind of surreal the number of doctors and nurses that came in to see me and were astounded at what I had done and the levels I’d reached,” Holt said.
“They didn’t believe it was caused by a gym session. It’s normally a car crash victim who’s been crushed or an older person who falls over in the house and is left lying for two or three days and their muscle breaks down.”
The international break means the former Scotland, Norwich City and Kilmarnock midfielder has only missed one Livingston game – a 2-1 win with assistant Davie Martindale in charge.
Holt admits “it was a shock to the system” and made him “realise I’ve got a wife and kids and other people to look after rather than just myself”.
“I hit it really hard with the kit man at the club – he’s a wee bodybuilder and still likes to compete and push you and I don’t do things by halves,” he recalled.
“It is just a lesson well learned I suppose. I am back down to normal levels.”