Impact of Exercise on Overnight Glycemic Control in Children with

Type 1 Diabetes (T1DM) Eva Tsalikian1; Roy Beck2; Peter Chase3; Tim Wysocki4; Bruce Buckingham5; Stuart Weinzimer6; Nelly Mauras4;

Craig Kollman2; Dongyuan Xing2; Katrina Ruedy2; William Tamborlane6 and the Diabetes Research in Children Network (DirecNet) Study Group. 1Iowa City, IA;

2Tampa, FL; 3Denver, CO; 4Jacksonville, FL; 5Stanford, CA; 6New Haven, CT

Hypoglycemia in children with T1DM

Studies in children and adults have demonstrated that the majority of severe hypoglycemic events occur at night and suggest that such events are more frequent following days of increased physical activity

Nocturnal hypoglycemia in children with T1DM

• Limited data are available regarding the role of afternoon exercise on overnight severe hypoglycemic events in children with T1DM

And • No studies to date have examined the impact of

exercise on asymptomatic, biochemical hypoglycemia during the overnight period using rigorously controlled research protocols.

The Diabetes Research in Children Network (DirecNet) is a multi-center study group whose objectives include the examination of factors that contribute to the risk of hypoglycemia and the development of strategies to prevent this complication of treatment of children with T1DM.

Aim of present study

• To examine the effect of late afternoon exercise that simulates common after- school sports activities on the frequency of overnight hypoglycemia.

We hypothesized that such exercise would significantly increase the risk of nocturnal hypoglycemia compared to a sedentary day without afternoon exercise.

Study subjects (n=50)

• Female 44%• Caucasian 90% • Age (yrs: mean + SD) 15 ± 2 • Duration T1DM (yrs: mean + SD) 7 ± 4 • Pump 54% • MDI 46% • HbA1c (mean + SD) 7.8 ± 0.8%

Study procedures

• 2 CRC admissions 1-4 weeks apart• Conditions:

– Same meals and basal and bolus insulin doses based on home regimen for sedentary day

– Exercise or rest between 4-6PM

• Glucose measurements– Q 15 min during exercise– Q 60 min from 6 PM to 10 PM– Q 30 min from 10 PM to 6 AM

• Primary outcome:– Glucose level < 60 mg/dL

Exercise protocol

0 15 20 35 40 55 60 75

TIME (minutes) 

Exercise Exercise

Exercise Exercise

Five minute rest periods

Exercise at 60% maximum effort (VO2max): Heart rate 140 beats/minute

All subjects achieved target heart rate for all cycles except for one subject that missed target for one cycle only

Treadmill

Glucose lowering effect of exercise

0

50

100

150

200

250

300

350

0 50 100 150 200 250 300 350

Glucose Value at Baseline (mg/dL)

Na

dir

Glu

co

se

du

rin

g E

xe

rcis

e (

mg

/dL

)

Treated for Low Glucose

75

100

125

150

175

200

2 PM 4 PM 6 PM 8 PM 10 PM 12 AM 2 AM 4 AM 6 AM

Me

an

Glu

co

se

(m

g/d

L)

Sedentary

Exercise

Mean glucose levels on the two study days

Exercise Period

4:00 – 5:15 PM

Percentage of patients experiencing nocturnal hypoglycemia (<60mg/dL) on

exercise and sedentary nights

46%

26%

6%22%

Exercise night only

Neithernight

Both nights

Sedentary night only

Nocturnal hypoglycemia by glucose level at bedtime

0%

10%

20%

30%

40%

50%

60%

Exercisenight

Sedentarynight

≤130 mg/dL >130 mg/dL

2/28=7%

8/22=36%

16/28=57% 12/22=55%

Bedtime Glucose

Summary

• 63% of subjects with pre-exercise glucose of < 130 mg/dL became hypoglycemic during exercise

• Lower mean blood glucose levels were observed throughout the night following a 60-minute period of moderate aerobic exercise, in the afternoon, in children with T1DM.

• Afternoon exercise increased the risk of nocturnal hypoglycemia from 28% to 48% when food intake and insulin regimens were not altered.

• On sedentary but not exercise days, nocturnal hypoglycemia was rarely observed when the 9 PM glucose was >130 mg/dL.

Conclusion

Our findings support the importance of modifying the child’s diabetes treatment regimen following afternoon exercise in order to reduce the risk of hypoglycemia.

• Barbara Davis Center– H. Peter Chase– Rosanna Fiallo-Scharer– Jennifer Fisher– Barbara Tallant

• University of Iowa– Eva Tsalikian– Michael Tansey– Linda Larson– Julie Coffey

• Nemours Children’s Clinic– Tim Wysocki– Nelly Mauras– Larry Fox– Keisha Bird– Kelly Lofton

• Stanford University

– Bruce Buckingham

– Darrell Wilson

– Jennifer Block

– Paula Clinton

• Yale University

– William Tamborlane

– Stuart Weinzimer

– Elizabeth Doyle

– Kristen Sikes

– Amy Steffen

• Jaeb Center for Health Research– Roy Beck– Katrina Ruedy– Craig Kollman– Dongyuan Xing– Cynthia Stockdale