The Effect of Insulin During Exercise on the Development of Low Blood Sugar in Individuals With Type I Diabetes
The Effect of Insulin During Exercise on the Development of Low Blood Sugar in Individuals With Type I Diabetes
Most children with type 1 diabetes have a drop in the blood sugar during exercise. This drop
 in the blood sugar can result in hypoglycemia (low blood sugar). In children using an insulin
 pump, there is an opportunity to reduce the basal insulin rate during exercise. This study is
 being conducted to determine if decreasing the insulin that is received during exercise will
 reduce the risk of hypoglycemia. We hope to learn more about how the body responds to
 hypoglycemia and to hyperglycemia (high blood sugar) when it occurs.

 As part of the study, children will have a visit on two different days. During each visit,
 children will exercise on a treadmill for about 60 minutes. During one of the visits, the
 children's basal rate will be continued during the exercise. During one visit, the basal
 insulin will be stopped. The blood sugar will be checked frequently during the exercise.
Each child will have two study visits. The visits will be between 1 and 4 weeks apart. The
 child will come to the research unit at the hospital at about 11:30 a.m. and will have lunch
 in the clinic.

 -  If the child has had a severe hypoglycemia episode in the 2 weeks before a visit or is
 ill at the time of either visit, the visit will be rescheduled.

 The parent and child will be asked if they want to use a meter to test the child's hemoglobin
 A1c at home. If they want to do this, they will be given the meter and asked to test the
 child's A1c two times on the day before one of the visits. The two tests will be done at the
 same time and they will also be asked to check the child's blood sugar at the same time. The
 test involves a fingerstick similar to testing the blood sugar level with a home glucose
 meter.

 At the start of each visit, a continuous glucose sensor will be inserted under the skin. This
 is done either in the stomach area, side, or buttock depending on which area looks like it
 will work best for the child. A special cream may be used to numb the skin before this sensor
 is placed. At the end of each visit, the child will have the option of removing the sensor or
 wearing it home for continued use.

 During each visit, blood samples will be drawn frequently to measure glucose and other
 hormones. To make the blood sampling easier, a small tube, called a catheter, will be placed
 in a vein in the child's arm. A special cream may be used to numb the skin before the tube is
 placed. The tube will stay in the vein while the child is in the hospital. There may be some
 itching, stinging or pain from having the tube in the vein. However, there should be no pain
 when blood is drawn through the tube. If the tube stops working, a new one will need to be
 inserted.

 -  Blood sugar measurements will also be made with a home glucose meter. Instead of doing
 fingersticks, blood may be taken from the tube to measure the blood glucose with the
 home glucose meter.

 -  Blood samples will be taken and sent to a lab before, during, and after the exercise.

 -  In all, there will be 24 blood samples taken (12 samples during each of the visits).

 During each visit, the child will be asked to walk on a treadmill.

 -  Before and after walking on the treadmill, the child will be checked for urine and blood
 ketones.

 -  During each visit, in the late afternoon, the child will walk on the treadmill for 15
 minutes followed by a 5-minute rest period. This cycle of 15 minutes of exercise
 followed by a 5-minute rest period will be repeated 3 times for a total of 75 minutes.

 -  During one of the visits, the child's basal insulin rate will be stopped at the start of
 the exercise session and will be restarted about 45 minutes after the child stops
 exercising. During the other visit, the basal rate will be continued. A process like
 flipping a coin is used to decide the order of the visits.

 -  For both visits, the blood sugar needs to be between 120 and 200 at the start of the
 exercise. Between lunch and 4 p.m., the blood sugar will be checked a few times. To
 lower the blood sugar to this range, the child may be given insulin through the catheter
 to be used to draw the blood samples. No bolus insulin doses will be given with the
 child's pump after lunch. If the study doctors or nurses think the child's blood sugar
 may be too low to start exercise, a snack may be given to get the blood sugar to be in
 this range. If the blood sugar is too high or too low and cannot be corrected quickly
 enough, the exercise for that day may be postponed. If this happens, the child will need
 to return on another day.

 -  About 30 minutes after the exercise has ended, the child's blood sugar will be checked.
 If it is less than 250 mg/dL, a snack will be given and the last blood draw for the
 study will be made 15 minutes later. If the blood sugar is 250 mg/dL or higher, no snack
 will be given and the child's blood sugar will be checked in 15 minutes. At that time
 the child's insulin pump will be started if it was stopped, and a correction dose of
 insulin may be given.

 -  If at anytime after the exercise session the child's blood sugar is 325 mg/dL or higher,
 the child's insulin pump will be started and a correction dose of insulin may be given.

 During each visit, the child's blood sugar will be checked frequently. If the blood sugar
 drops to 65 mg/dL or lower, the hypoglycemia will be treated with carbohydrate. The child
 will not be treated if the blood sugar is higher than 65 mg/dL.

 Dinner will be given to the child at about 6:00 p.m. A bedtime snack will be given to the
 child to take home. The snack will be based on what the child would normally eat on a day
 with exercise.

 The child will be instructed to not have any more exercise for the rest of the day. The child
 will be given a home glucose meter and asked to check his or her blood sugar prior to the
 bedtime snack, at midnight, 3 a.m., and before breakfast the next morning. The child will be
 asked to treat any blood sugars 80 mg/dL or lower and to record the information on a log that
 will be provided.

 If the parent and child decided to do the A1c meter study at home, at one of the visits the
 study staff will check the A1c using the meter and the DCA2000. A fingerstick blood sample
 will also be sent to the central laboratory. The child's blood sugar will also be checked at
 the time of the tests.

 The catheter for the blood draws will be removed and each visit will end at about 6:30 p.m.
Inclusion Criteria:

 -  Clinical diagnosis of type 1 diabetes for at least 18 months (The diagnosis of type 1
 diabetes is based on the investigator's judgment; C peptide level and antibody
 determinations are not needed.)

 -  HbA1c <10.0% (The DCA2000 will be used to assess eligibility.)

 -  Age 8.0 to <18.0 years

 -  Weight >39.5 kg at reinfusion centers and >46.0 kg at discard centers

 -  BMI >5th and <95th percentiles for age and gender

 -  Stable insulin regimen for at least 1 month and not anticipating a change prior to the
 subject's completion of the study (Stable is defined as no change in the overall
 insulin program, i.e., no change from SC injections to pump.)

 -  Insulin regimen involves use of an insulin pump

 -  Normal thyroid function (measured within the previous year)

 Exclusion Criteria:

 -  A recent injury to body or limb, Addison's disease, muscular disorder, use of any
 medication or other significant medical disorder if that injury, medication or disease
 in the judgment of the investigator will affect the completion of the exercise
 protocol

 -  Asthma which has been medically treated within the last year

 -  Current use of glucocorticoid medication (by any route of administration)

 -  Current use of a beta blocker medication

 -  Use of pseudoephedrine 48 hours prior to visit (if used in the 48 hours prior to the
 scheduled visit, the visit will be deferred)

 -  Severe hypoglycemia resulting in seizure or loss of consciousness in the 2 weeks prior
 to a visit (if a severe episode occurs within 2 weeks prior to the scheduled visit,
 the visit will be deferred)

 -  Active infection (if at the time of the scheduled visit an infection is present, the
 visit will be deferred)

 -  Anticipating a significant change in exercise regimen between visits (i.e. starting or
 stopping an organized sport)