I am another that says you should do what you can. I first started exercising using the same principle. I was much bigger than you, but I found that I could pretty easily have 3 sessions of 10 minutes of walking. Even after I lost a good bit of weight and increased my exercising, I found the three short sessions of walking helpful. For one thing, since I walked on my breaks at work, it kept me out of the break room and away from the vending machines.

Exercise when you know you'll do it. I have a hard time fitting in 30-40 straight min (unless it's a rainy day) so I do a quick work out in the morning, then one in the evening, and sometimes even one later at night. It all depends on how my day goes.

There's some very solid evidence from studies by Standford and Johns Hopkins that says you still get very much benefit from mini sessions of exercise. I say do what you can and work on your personal bests! Don't care where you have to start, as long as you start somewhere.

Here's a write up on some of those studies. Very encouraging for those who are tight on time and/or can't tolerate much activity at once.

http://www.tinajuanfitness.info/articles/051705.htm

4star - thank you for that link!

and thank you to EVERYONE who commented - I appreciate your input!!

This! Someone on these boards once said "I exercise for fitness, I eat well to lose weight." That stuck with me big time. I get my heart rate into cardio level and just go. I exercise to be strong, to have healthy insides and I eat less (and healthily) to lose the weight. It's a different mindset, but when I'm less focused on the weight loss side of exercise and more on the fitness side I notice things from that angle. Things like "Hey! I went an extra 5 minutes or boosted my resistance or did an extra set, etc." I pay more attention to the signs that I'm getting healthier and not just the number on the scale.