Brian Shields used to “love the heat”, but now, living with multiple sclerosis (MS), means the current heatwave can leave him unable to move.
He said high temperatures affect him “hugely”, forcing him to stay in the shade or in a cool room to avoid his muscles weakening.
In Northern Ireland on Thursday the highest temperature of the year so far was provisionally recorded as 30C in Castlederg, County Tyrone.
Heatwave conditions for Northern Ireland were met on Wednesday after 25C was recorded for three days in a row – a threshold set by the Met Office, external.
“Before my diagnosis, in weather like this I would have been sitting out sunbathing,” Brian said.
“But now I have to be in the shade, in a cool room, because otherwise the heat really affects my muscles.
“It would mean I wouldn’t be able to lift my arms or lift my legs or do anything, you’re just there, but that’s just the heat that does it, so I just stay out of it.”
MS is a condition that affects the brain and spinal cord, external, according to the NHS.
It has a number of symptoms, including extreme fatigue, vision problems, and muscle cramps.