Last night I couldn't get to sleep because I felt ill. I was shivering although I felt hot. The weather was really hot yesterday, even though it's Scotland, about 26 deg C. I had the window open fully and threw the blanket off me and was still shivering. I felt so tired, yet I couldn't sleep.

I eventually did get to sleep but still didn't feel great this morning. I did rule out having the cold or flu as I'm now feeling fine, but I'm wondering what caused this.

I went for a 4-mile run yesterday, which is something I don't normally do, although I'm planning to make a habit of it.

Does anyone know of these kind of symptoms being attributed to running or the start of a training regime on a body which is unaccustomed to it? Or do you have another explanation?

You may have given yourself heat stroke, or just straight up over exerted yourself.

You may have also been suffering from dehydration/lack of nurishment. did you eat properly and accordingly to doing more physical activity than usual. Did you drink extra water to make up for what you sweated out?

Otherwise, I can't think of what it might be, other than sometimes the body does weird shit. it may have been a 12 hour flu, or mild food poisoning.