It is very common here and most believe that if you expose your body to cold after being hot then you will die, or be at risk of death. This would include opening the fridge after ironing, or whilst sweating. However like many superstitions there is some basis in fact as going from heat to cold can cause shock and even death as sudden change to cold water constricts the blood vessels and can affect the heart. When I was a diving instructor in the Mediterranean where the water is much colder than here, we would always advise divers to put their wrists into the cold water before diving off the boat, especially if they had been in the sun for a while. I doubt that opening the fridge after ironing would have the same effect, but I can see where it comes from. Matilda