Exercising in parts: as effective?

Hi,
I was wondering if doing exercise in ltitle bits instead of all at once is less effective and how less effective it is.

For example is doing 5 sets of 10 pressups an hour apart as effective as just doing 50 pressups in a row? And if not how less effective is it.. does it's effectiveness decrease the longer you leave between doing each set of reps?

THANKS FOR ANY HELP.

Increase sets gradually

If you're just starting out with exercising, you might find that by the time you get to near 50 press-ups you'll be worn out so you won't be as accurate with your movements. I think doing shorter sets is better, as your heart rate gets chance to return to normal in between sets. As you get more used to it, you could increase your sets, say from 10 to 15 then to 20. Hope this helps a bit