Abertawe Bro Morgannwg University Health Board says many of the people it has been treating have cardiac problems or have suffered a stroke. Many are over the age of 85.
The health board says it has brought in extra staff, and put on extra beds, to deal to with its A&E departments being exceptionally busy.
It says most routine operations have been postponed.
More top news
Wales got their 2016 Six Nations campaign under way with an entertaining 13-all draw with Ireland at the Aviva Stadium.
Mosques across Wales and the rest of the UK have opened their doors today to encourage people to find out more about the Islamic faith.
Rain quickly clearing this evening with blustery, locally heavy, showers following, merging at times into longer spells of rain.