How do I know if the water is "cold" versus "too cold for swimming"? And what are some precautions for avoiding hypothermia?
In a month or so I'll be moving somewhere with a pool. Given that the access is free, I'm thinking of swapping my gym for the pool for exercise (I go to the gym 5/7, 2 days for cardio and 3 for muscle training) as I really like swimming.
However, the pool is unheated and positioned such that it is shaded for most of the day, and it is currently the middle of winter here in Brazil. Being a tropical country, it isn't as severe as somewhere up north, but it still feels a little dangerous to go swimming when it's under 20º C (68 F) out as I've never done it. I'm not an experienced swimmer by any means, but I know how to swim, except I've only ever swam in hot weather or heated pools.
I wouldn't be swimming very long, I figure 30 min a day should be about good enough to keep my current level of fitness (if not too much!), so I'm not sure if I should be worrying too much about hypothermia or not in these circumstances. I would like to eventually build up tolerance for the cold water but I'm wondering if it wouldn't be wiser to start up in the spring instead. What do you think?
Thanks in advance!