Why is it that people have asthma attacks while they are sleeping and can it eventually kill you?

Nocturnal asthma: Asthma symptoms that occur at night (usually around 2-3 am) is a problem if it occurs more than twice a month. This can mean the asthma is not controlled. The reasons are many-lower blood cortisol level, breathing in indoor allergens and/or cool dry air, and other reasons we don't understand. Death from asthma is uncommon but preventable. See your allergist.