HI there, always nice to talk to a fellow juice faster. Ive read up looking for the answer to the exact same question as i like to JF and do treadmill, aerobics and a few weights....well the advice ive read does not recommend 'long distance running or weight lifting or intense excersise'. well I run about 8km and i wldnt call that long distance at all, 45 mins of aerobics wld be the same and i think an hour of karate wld pretty much equal the same. I think as long as we tune in and listen to our bodies we know how far we can push ourselves, have a really good veg juice b4 hand and i think if yr energy levels are good then go for it carefully. See how it goes basically and im sure if yr sensible itll be fine, im not a health practitioner but ive fasted a lot and this is the first fast with excercise and it seems fine, but youll be really hungry after so maybe take a shop bought smoothie along as an emergency if youre allowed that on yr fast ! Love Emma.