I Don't Have Any One Else To Ask, If An

I don't have any one else to ask, if an older person (around 70 years) is diagnosed with light heart murmur, can anything be done to prevent it from getting worse? Doctor said to keep the person out of hectic heat and to monitor heart rate and such. Is there anything else that can be done?
It's not bad enough to require treatment yet, but I don't want it getting worse..