I know Yoga is supposed to increase circulation. However, I've been practicing for about 6 months - 2-4 times per week. While in certain poses - my legs feel like they are falling asleep - tingly, etc. Is this normal? Examples of posesn where my legs start to tingle - forward fold, down dog, half way up pose, seated forward fold.

My legs and hands also fall asleep easily while sitting down.

The "pins and needles" sensation of your legs feeling that they are falling asleep is usually due to a compression of muscle or bone against nerve. This is a fairly normal sensation in newer students and usually goes away with time as you gain flexibility and range of motion in the joints.

I am a bit concerned that this is occurring when you are sitting down (in a regular chair?) as this could be a sign that you have some sort of nerve compression in your back. (Although it's not clear due to lack of details in your post.) You may want to mention this to your MD on your next visit to him/her.

Thank you so much for your response.

Actually - I have a slight stress fracture in the L5 vertebra of my back. It's been there for years - I actually forget about it because I don't feel pain where the actual fracture is. I didn't think that this could be causing it. My doctor told me not much could be done about it except for strenghening the muscles around it to protect it. Do you think this could cause the tingling? I should probably see the doc again (it's been a few years). I guess my concern is doing more damage by doing yoga. No pain - just the tingling.

The tingly feeling is the very beginnings of nerve compression, if it was severe you would feel shooting pain and numbness in the extremities. If you experience these more pronounced symptoms I would definitely see your MD.

Your injury could indeed be a factor here, especially since L5 would be stressed in forward folding poses. Once thing to experiment with is to keep the low back super straight in the forward fold poses and see if this decreases the tingles.