Mr Glenn Roeder was admitted to hospital early yesterday evening after being examined by the club doctor.
He is currently in a stable condition and further tests will be carried out today.
We are pleased to confirm that despite numerous press reports, the nature of the problem is not related to a heart condition.
No further statement will be made until the results of the tests are available.
Further information will appear on the official West Ham United website - www.whufc.com - when available.
The Roeder family would like to thank supporters and people within the football world who have sent goodwill messages.
At this time, we would ask that people respect the privacy of the family.
Any further messages of goodwill should be directed to the Football Club.