Nails turn blue while doing cardio exercise

I wasn't sure where to post so I hop it's okay to post it here.
I'm in my 20's and have been going to the gym for years now,
I'm very healthy and have always been active.
For the past 3 months, about 15 minutes (like clock work)
into my exercise, my nail beds will be blue. I have no SOB or anything
abnormal like that. Has anyone heard of this happening to someone they know
or has had it happen to them? Any leads as to what this could possibly be would be great.
Thanks~

[ireneo]

This is something you should mention to your doctor. My hands and feet turn grayish blue (including nail beds) but I have Raynauds - kind of a vasospasm of the small blood vessels in the hands and feet. Difference is mine happens when I'm cold, stressed or sitting or standing too long. There is a test for Raynauds where they check the vessels in the nail beds. But your situation seems directly tied to exercise so it would be best to ask your doctor about this one.