I'm sure moderate exercise, non polluted oxygen and so forth are helpful at any stage. As all the things we already now (rest, exercise, healthy food, etc.). But I have trouble accepting theories which are based on things that can not be quantified. We'll have to wait 60 years to asses and I'm pretty sure the results will depend mostly on standard-well known facts like family status, family income, schools etc. than the mother doing 'exercise' when the subject was a fetus.