Doing a bit of breath holding training in the bath. I didn't push myself too hard, safety first. I do four cycles with breath holds of 1:30 minutes. The breathing intervals reduce from 1:30 down to 45 seconds. At the end I challenge myself to a longer breath hold, just for fun. I chit chat a bit before and after breath holds. This type of training helps increase my tolerance to the excess Co2 that comes from holding my breath.