I m a weightlifter, I workout pretty heavy. on most workout days everything is fine, but when I do super-sets about 15 mins into my workout I start feeling weak.a little light headed.and feel like I m going to get sick and my hands shake a little. this lasts for about 30 min. I ve been lifting for about 15 years but just started doing super-sets about 6 weeks ago. I m 39, don t smoke, don t drink and my diet is very good (about 2200 cals, 160g protein, and 210g carbs a day).My resting BP is 140/80 and pulse if i remember right is 77 bpm. any Ideas ?