leg falling asleep

I'm 45 years old and an avid exerciser.  I do yoga, strength training and treadmill before yoga classes.  I average 6 hours exercise a week.  I've only started doing yoga in the past 4 months.  I'm noticing when I'm driving and when I sit a long period of time my right foot is beginning to fall asleep and I can kind of feel that sensation up and down my leg.  I'm wondering firstmost if possibly the yoga stretching in my hips might be part of the problem.

I do have sensitivity and have had sensitivity since my 30s in my limbs and spine.  It's improved as I've learned I'm extremely sensitive to caffeine.  I found I was having pretty severe reactions to caffeine in that I would have much pain in my occipital lobe (headache evolving back pain) that radiated into my spine and the base of my skull.  I also had stiffening and soreness in the base of my spine.  It also affects my toes (makes my toes curl, so to speak).  I had extreme difficulty going to sleep at night and found when finally going to sleep, it would abate in my sleep.  All these problems resolved when I quit drinking coffee.  I've had on a couple of occassions some gout possible in one of my fingers on one hand.  Most of it simply goes away when I just don't have caffeine.  

I've been drinking GreenTeaHP with has I think about 45 mg of caffeine.  I really haven't been suspicious that it has been the cause of my recent reoccurence of this problem.  I hope it's not, but wanted to check.  I'm also experiencing some mild twitching in my thumbs.