Cycled for 3.4 miles today, first time I've been out on my bicycle in ages. After about 15 minutes I had to stop for a 4 minute break (going up a step section of path covered in tree roots on the local common), then at the half hour mark I had to stop again, having seriously overdone it, for 8 minutes. Really felt I was going to throw up and/or pass out. Thankfully I did neither and got home safely. Another sign I really need exercise!