Doctor Says Dressing Modestly is Dangerous for Heart Patient

I have been diagnosed with a heart condition that is aggravated by wearing heavy clothes in a warm environment. My doctor gave me instructions to wear as little clothes as possible when it’s hot. She says dressing the modest way I have been doing for many years is actually detrimental to my health. She has advised me to wear only loose fitting sleeveless tops when it is hot in the summer and short sleeves in spring and fall weather. She said shorts are preferred, but knee-length elastic waist skirts or sundresses are okay too. If I don’t follow this, I could be hospitalized and my life could be on the line. What am I supposed to do if the doctor tells me not to dress modestly?