In the summer I work as a lifeguard - I've been trained in CPR/AED first aid
Interesting. How long is the training in order to do something like that?
It took several weeks of steady training - it was important to do because I am responsible for the safety of people in an area of water
Do you need to have any kind of medical background to do this training, or can anybody attempt it?
You do need to be a strong swimmer, but it's a good idea to get trained using aids and equipment
I see. Have you ever had to rescue somebody in a body of water so far/employ your training that you've learned?
Yes, I've had to rescue a few people - sometimes I even have to carry out mountain rescues
Wow, that sounds intense. What are their reactions usually when they see you or come to? Very thankful I would imagine?
They are thankful as well as relieved!  It makes being  part of the emergency services system worthwhile!