Hello, is it too late for me to join?
Dh and started the shred on Sunday, so we are now on level 1, day 3.
We are both very unfit, although dh isn't really overweight. I on the other hand have lost 23lbs since June 16th using My Fitness Pal, have just over another two stone to go and have been trying to build up my fitness level by walking after a long period of illness running from Autumn last year to May this year.
I found the first day hard, in fact everything went silver at one point and I thought I was going to pass out, but I think that was because I got up early and did it before breakfast.
As voldemort said, if I'm still for too long my muscles seem to seize up and when I wake in the morning I feel like one great big knotted muscle, but it does ease of once I get moving - although I look quite silly going up and downstairs at the moment. 
The worst for me has been my calf muscles, they seem to hurt pretty much all of the time. I think its the bicep curl and dips that's causing it.
I did find it easier to get through the whole thing without any of the 5 second breathers she allows today, but ran out of steam a bit on the cycle crunches at the end.
I also had someone comment on my biceps earlier today and when I checked I was gobsmacked to find I'm actually starting to develop some arm definition after just three workouts - which is amazing. 
I've heard its supposed to get a bit easier and less painful by days 5/6, so am holding out for that now.
Not sure if I'm going to stick to the 10 days for each level, or wait until I am finding each level easy-ish before moving on - what is everyone else planning to do.
Oh - and I read on another board that Jillian doesn't recommend working out 7 days a week and on her other dvds specifically says not to but to take at least one day a week of for recovery. Is everyone else intending to do it 7 days a week or are you thinking of taking a day off?