Need some help with a child that has already had a heat stoke?

ok my daughter has already had a heat stroke at the ago of 7 last summer i kelt her inside all summer long, this summer she really wants to go outside and play with her friends, i am so worred to let her out to play. she goes to a summer program were they go out side alot and she really wants to beable to play with the other kids, i just dont know what i can do so that she can have a fun summer and not have another heat stoke,,,please any thoughs ???