Yeah, started lifeguarding when I was 16 and did it every summer for years. Good job with cool coworkers I'm still friends with.
It was kind of stressful though, despite lifeguards looking like they're just chilling 98% of the time

Another pool nearby had a kid drown in front of everyone unnoticed, like Andrex pointed out it's common.
I was fortunate because my oldest sister was a lifeguard so besides nepotism getting me my first job, she pushed for me to take swimming lessons growing up.
My family would also go to Maine a lot as a vacation spot so I was always swimming in murky ass lakes, cold ass oceans, etc.