cna work is very exhausting..so your energy and stamina will help....as far as heavy pts. most facilities i work at have a hoyer lift...(to transfer from bed to chair...chair to bed etc....) and your fellow co-workers are there to assist you in pulling them up in bed ,turning them and what not.....i to am a petite person....i am no longer a cna... but when i was i never had problems with lifting...so dont let that discourage you.... good luck to you!!