September 18, 2006
Exercise and Sports
Question from Augusta, Georgia, USA:
I am hypoglycemic and have started a weightlifting routine. I find that after my workout, my sugar is high and then drops to low. This is keeping me from sleeping at night. I have had this problem before and my doctor can't seem to give me a straight answer. He tells me to keep lifting weights. I would like to continue to do so, but my sugar seems more unstable. Do I need a longer recovery time for my muscles? I just don't understand what is going on. When I first started lifting, I had no bad side effects as far as my sugar goes, but when I starting lifting heavier weights, the symptoms came back, i.e., restless sleep, feeling my heart beat much faster, sudden rise and fall of my glucose level.
Lifting weights can cause blood sugars to rise during the activity and fall hours afterwards. The body secretes counter-regulatory hormones (i.e., epinephrine, cortisol, glucagon, growth hormone) signaling the liver to release glucose during intense exercise like weightlifting. There is the factor of insulin on board though. Too much insulin in the system may override this process. The more intense the lifting (i.e., heavier weight), the higher it can go. This activity is considered anaerobic or without oxygen, which may cause sugar levels to go up.
Other techniques to reduce blood sugar, other than insulin, would be to drink plenty of water and avoid a “valsalva maneuver” which is holding your breath during the lifting phase. The safest and most efficient way is to breath in through the nose just prior to the lift and exhale through the mouth on the lift or push/pull phase.
The restless sleep probably has nothing to do with diabetes. It may be the muscles reacting to a tough workout. A faster heartbeat during a heavy lifting routine is normal. If it increases afterwards, it would probably be best to talk with a cardiologist to rule out any heart abnormalities.