On Sunday a newspaper claimed that he had had a stroke but Glenn, currently convalescing at his home in Shenfield, who was kept, as a precautionary measure, on a life support machine for five days, stresses:
"I never had a stroke and my heart is fine, but I was kept 'asleep' for five days so I had my eyes closed to the world in that time and it was not so nice for my family.
Glenn, who is looking to resume preseason training with the players on July 1st, adds:
"My condition was a benign tumour and is not related to stress; it could have happened to a bank manager or a factory worker and my heart is fine; neither was it a stroke - I blacked out because the tumour had reached a certain size.
"The tumour was apparently a slow-growing one although no one can say exactly how long it had been there - what happened that day was going to happen at some time, but it could have been much worse, because if I had blacked out half an hour later I would perhaps have been driving home with two of my children in the car with me, and that doesn't bear thinking about."
"I have had brain surgery, everything has been hooked out, I have not needed radiotherapy, and although I have had excruciating and horrible headaches - and have been housebound for a while - I may have lost some fitness, but no strength.
"A histology has confirmed that the tumour was benign, and it was at the front of the brain which no one uses.
"Apparently we only use a third of the brain, though in 1000 years it might be two thirds!
"I must thank everyone who has helped me - the medical staff are miracle workers, but when I was first told it was a tumour my reaction was 'they are going to tell me how long I've got.'
"That must have been hardest to bear for Faith and the family, seeing me there with tubes coming out of everywhere, motionless, looking to all intents and purposes like I was dead.
"But I remember everything about the day, the Middlesbrough game, Trevor Sinclair scoring the winner late on, the TV interviews, and the press conference."
Glenn admits the ordeal has changed him and adds:
"This experience has taught me so much, not least that the medical staff who cared for me are the real stars in this world - not footballers; they truly are unsung heroes, the silent superstars who don't seek the limelight, but every day save lives.
"The nurses were tremendous; they have smiles on their faces as they work their 12 hour shifts simply because they care about people.
"I know there is a chance that brain surgery can affect personality but I am told by those around me that I am just the same - which must be a disappointment to my wife!"
Glenn has been closely involved in the planning of preseason training - though all the dates are yet to be confirmed officially - as well as the release of players at the end of their contracts this summer.
"I have to take it easy for a bit, though," he admits, "and this is the first time I've been on a lead in my life, so it is not easy.
"It's a small price to pay though, after everything that has happened, and every day I feel stronger - I'm still taking 14 pills a day but they are gradually being reduced.
"I expect to be literally up and running by the 1st of July - and this has made me more determined to keep going because, as far as I am concerned, there is unfinished business.
"I was very much a 'hands on' manager before my illness and perhaps I will have to delegate a little in the future - but I have never given any thought to packing it in.
"The response I have received from people has been overwhelming; I have had cards and letters from New Zealand, USA, Australia, China and people within football have been so kind as well - all but a couple of Premiership and Nationwide League club managers either sent faxes or letters, and it just goes to show me that there a lot of good people out there, the silent majority, if you like.
"There were times when I lost faith in human nature - but that has been restored; it has made me realise there are quite a few people out there who think a lot of me, and that means so much when you are feeling low."
As for matters football, and West Ham's relegation, he adds:
"I had a good first season and we finished seventh; a lot of people were for me then but I accept some of those will be against me now because we have been relegated.
"Now, managers will no longer believe that 40 points are enough to stay up though because we managed 42 and went down.
"Injuries to key players at key times cost us dearly; we lost 15 games in my first season and finished seventh, yet we lost just one more last season and went down."
Regarding next season, he says:
"I only want players next season who are prepared to put the team before themselves, who show their individual skill within a team framework - we want 11 players moving in the same direction."