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From Bellingham, Massachusetts, USA:

My daughter has type 1 and is as elite competitive swimmer. She was doing well with meets and control until puberty, which typically is a difficult period of adjustment for female swimmers. She was started on Lantus, Humalog and NPH injections two months ago. Why is she showing ketones after racing the 1000 or 1650 meter races? When she has trace ketones, she is symptomatic with severe stomach cramps and headache. This is usually her best event, but she has been advised to stop swimming distance. What can we (parents and coach) do to help? She is usually fine maintaining her distance per stroke until the last 300 to 500 meters.

She takes a sliding scale of Humalog dependent on the number of carbohydrates, plus 12 units of NPH at breakfast, nothing at lunch, a sliding scale of Humalog at supper and Lantus at bedtime.

The races are variable. Usually, during the school year, distance events are Friday evening after school with a 5 p.m. warm-up and 6 p.m. start. It can be her turn anywhere from 6 to 9 p.m. Obviously, there are issues with supper and I try to have her eat a small meal before warm-up and snack before the race. She eats a small meal after the Friday session because, if not, she is low during night which becomes a problem the whole next day.

Saturday/Sunday sessions typically are 7 a.m. warm-up, 8 a.m. start. She usually has no problem with warm-up; the problem is with the races afterwards. I am supposed to reduce her Humalog by one unit on race days.


Swimming long distances, along with hormonal changes during puberty, can make it difficult to control blood sugars. I would speak with the doctor to see if making the insulin regimen (Lantus, NPH, and Humalog) simpler. NPH is not very predictable, especially around exercise. Using Humalog and Lantus may be easier to control the swings as would using a pump, which would mean using only Humalog. An athlete can often keep the pump off for an hour at a time without any significant increase in blood sugars.

If ketones are present (due to high blood sugars) towards the end of the event, it may be due to the adrenaline kicking in for a final kick. It is common to have two different plans for insulin adjustments, one for practices and one for competition. During competition, athletes often fight high blood sugars, depending how much insulin is on board. If blood sugars consistently go high during competition, it may be worthwhile discussing with your healthcare team about starting with a lower blood sugar (i.e., 110 mg/dl [6.1 mmol/L] as opposed to 150 mg/dl [8.3 mmol/L], for example) than a normal pre-exercise level.

For high blood sugars and ketones present after competition, athletes should immediately get water into their system. Drinking 16 to 24 ounces of water will help eliminate the ketones. Using insulin to bring down high blood sugars after competition is another technique, but should be used with caution. Once hormones are decreased in the body, the exercise may have a lowering effect of blood sugars causing a low blood sugar a couple of hours afterwards or up to 24 to 36 hours later. If this technique is used, checking blood sugar levels within 20 to 30 minutes is paramount to avoid severe low blood sugars. As always, any changes in insulin should be cleared by your healthcare team first.


Original posting 7 Jul 2006
Posted to Hyperglycemia and DKA and Exercise and Sports


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