Hospitals in the area with Wales and England’s worst Covid death rates are only coping by postponing urgent surgery such as cancer operations.
Cwm Taf Morgannwg had already suspended some non-emergency services but the boss of the health board said they have now paused some urgent procedures.
Cwm Taf covers Rhondda Cynon Taf and Merthyr Tydfil, which have the highest and second highest Covid death rates.
“It’s tough times,” said Cwm Taf’s medical director Nick Lyons.
It comes as NHS bosses said the number of Covid patients in Welsh hospitals is double April’s peak and that 66 more people in Wales had died of the virus.
Mr Lyons said on Wednesday night their field hospital Ysbyty Seren in Bridgend had 74 patients, people they “wouldn’t have been able to accommodate within our usual hospitals”.
“We are coping, but that’s coping because we’ve been cancelling urgent surgery.
“We even had to cancel some cancer surgery over the last few weeks,” Mr Lyons told BBC Radio Wales.
“My heart goes out to families and to patients with all the stress and the worry that gives.
“It’s tough times and we’re all in it together, and we do see that optimism, that glimmer of light at the end of the tunnel but it’s hard.”
Welsh NHS Chief Executive Andrew Goodall said on Wednesday that 2,870 Covid patients were being treated in Welsh hospitals – with 36% of all patients have Covid, which is twice the proportion in May.
In the Cwm Taf Morgannwg area, which covers Bridgend, Merthyr Tydfil and Rhondda Cynon Taf, more than half of hospital patients have the virus.
In Rhondda Cynon Taf, the Covid death rate is 283.9 per 100,000 population – followed by Merthyr Tydfil where the death rate is 253.6.
“It’s an absolute tragedy for the families and the loved ones and very sobering,” said Mr Lyons.
“We’re coping but only because of the dedication of our staff, and it’s immensely humbling to see people giving up their spare time coming in doing extra shifts, but the toll on them is immense.
“In practice our hospitals are full and although we are coping that we’re only coping because we’ve cancelled all but the most urgent surgery.
“We’ve redeployed staff who’ve been incredibly flexible from places they normally work such as outpatients.”
The health board oversees three hospitals – Prince Charles Hospital in Merthyr Tydfil, Princess of Wales Hospital in Bridgend and the Royal Glamorgan in Rhondda Cynon Taf.
A nurse at Royal Glamorgan Hospital, near Llantrisant, said earlier this week how she felt “overwhelming fear” as 13 ambulances queued outside her hospital’s A&E department.