Which measure is NOT advisable for treating a rattlesnake bite?

Applying heat is not advisable for treating a rattlesnake bite because heat can exacerbate tissue damage and increase the rate of venom absorption into the bloodstream. Rattlesnake venom can be potent and quick-acting, making immediate medical treatment critical. Instead, the focus should be on keeping the affected limb still to slow down the spread of the venom and seeking medical attention as soon as possible, as antivenom may be necessary. Additionally, attempting to suck out the venom is also not effective and can lead to further complications. Overall, applying heat contradicts established medical guidelines for snakebite treatment and can be harmful.