I've heard that overheating during pregnancy is dangerous - but how hot is too hot? On saturday It was a beautiful warm day outside and we went for a walk with a couple friends along the sea. There was no wind. We walked up a large flight of stairs up the face of a hill and wow, when I got to the top I could not breath and I felt like I was going to pass out from heat exhaustion. I actually blacked out for a couple seconds. I was seriously hot - I would consider that overheating. But at what poing does one say "now I've had enough"? "I'm geeting too hot now"