I know I'm not as fit as I used to be, but I swam 12 lengths in the pool earlier (lunchtime), and I was exhausted this afternoon - ended up falling asleep for 3 hours.
I was fine at the time (took a short break after each 2 lengths, ie each time I got back to the shallow end), and my heart rate never went above 110.
I'm a busy working single mum, and always a bit short on sleep, but good at keeping going, and this was the first kid-free and work-free day in several weeks.
I had SO MUCH planned to do today, and only got about 1/3 of it done. How could swimming just 12 lengths have knocked me out like this? Am I really that unfit?