Im so untoned that tbh I haven t noticed much, I'm on day 9 of it (and day 3 of ss) but have done the full 30 days before, last time I noticed my fitness levels really increasing but this time since on ss it is a lot harder lol but I can do it & take my fitness seriously and believe that is the key to me keeping weight off long term, I only have 2st to lose so wanna keep working on fitness.
But it depends on ur fitness levels I guess... If u r really unfit then prob best not to undertake anything to strenuous- if like me ur reasonably fit then carry on with what feels ok for u, I can't run whilst on ss like I did before :-/