My son is 15 and started weight training about a year ago. Recently, he has picked up the pace to add strength for the next hockey season. His blood sugars go through the roof, over 300 mg/dl [16.7 mmol/L], after a heavy session. Is it from the muscles releasing glycogen?

Also, when he plays hockey, he starts out at a normal blood sugar level, but after he is usually over 250 mg/dl [13.9 mmol/L]. Is this also from the muscle glycogen? What can help? His endurance slows considerably at the end of a game and is holding him back. Any help would be appreciated.

High intensity sports like weight lifting can lead to hormones being released in the body causing the liver to release glucose. This type of glucose is the stored form which is called glycogen. Any high intensity sport or anaerobic activity can lead to a spike in blood sugars. The challenge is what to do with a high blood sugar during or after exercise. The easy answer is to give insulin and drink a lot of water but there are risks involved with this approach.

There are several studies showing a spike in blood sugars during or immediately after weight lifting, but then a drop in blood sugars hours afterwards. One technique is to give insulin if blood sugars are significantly high after exercise (i.e. over 300 mg/dl [16.7 mmol/L], but it is recommended to check blood sugars relatively soon, within 20 to 30 minutes, to see where the blood sugars are headed. A delayed, or often called lag, effect is where blood sugars will drop hours after exercise and this presents a problem when insulin is given for high blood sugars. This technique should be discussed with the healthcare team prior to implementation because of its high risk nature.

RP