Sheri R. Colberg, Ph.D.Sheri R. Colberg, Ph.D.

Old Dominion UniversityOld Dominion University

Norfolk, VirginiaNorfolk, Virginia

Exercise & Busy Kids – Exercise & Busy Kids – Preventing and ManagingPreventing and Managing

HyposHypos

““Diabetic Athlete” - An Oxymoron?Diabetic Athlete” - An Oxymoron?

No! There are many diabetic athletes No! There are many diabetic athletes worldwide competing even at elite levelsworldwide competing even at elite levels• Chris Dudley (NBA basketball)Chris Dudley (NBA basketball)• Jay Leeuwenburg (NFL football)Jay Leeuwenburg (NFL football)• Kris Freeman (U.S. XC ski team)Kris Freeman (U.S. XC ski team)• Gary Hall, Jr. (Olympic swimming)Gary Hall, Jr. (Olympic swimming)

Many others have run marathons, done Many others have run marathons, done triathlons, and competed in every type triathlons, and competed in every type of sport and physical activityof sport and physical activity

Goals of Exercise ManagementGoals of Exercise Management

Prevention of hypoglycemia during and Prevention of hypoglycemia during and after any physical activityafter any physical activity

Rapid management of hypos caused by Rapid management of hypos caused by exerciseexercise

Prevention of hyperglycemia and DKAPrevention of hyperglycemia and DKA Optimal athletic performanceOptimal athletic performance

Effects of Low BG on ExerciseEffects of Low BG on Exercise

Early, rapid-Early, rapid-onset fatigueonset fatigue

Potential loss Potential loss of coordinationof coordination

Reduced Reduced enduranceendurance

Decreased Decreased performanceperformance

What Is Optimal BG for Exercise?What Is Optimal BG for Exercise?

Varies, but most athletes perform best Varies, but most athletes perform best with BG levels of 80-180with BG levels of 80-180

Some start out higher, but few lowerSome start out higher, but few lower

50 75 100 125 150 175 200 225 250 275 300 325

BG (mg/dl)

Fuel Use and Acute Effects Fuel Use and Acute Effects of Exercise on BG Controlof Exercise on BG Control

Exercise Energy SystemsExercise Energy Systems

The way energy is produced and used The way energy is produced and used during an activity affects BG useduring an activity affects BG use

Three distinct energy systems exist:Three distinct energy systems exist:• Immediate (phosphates, or ATP-CP)Immediate (phosphates, or ATP-CP)• Lactic acid system (rapid glycolysis)Lactic acid system (rapid glycolysis)• Aerobic (oxygen)Aerobic (oxygen)

Their use is a continuum and depends on Their use is a continuum and depends on exercise type, duration, and intensityexercise type, duration, and intensity

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Exercise Energy SystemsExercise Energy Systems

Fuel Use during ExerciseFuel Use during Exercise

For most exercise, carbs are main fuel: For most exercise, carbs are main fuel: glycogen (~80%), BG (20%)glycogen (~80%), BG (20%)

Romijn JA, et al., JAP, 88(5): 1707-1714, 2000

Fuel Use during ExerciseFuel Use during Exercise

BG uptake into muscles occurs 2 ways:BG uptake into muscles occurs 2 ways:• Insulin-mediatedInsulin-mediated• Contraction-induced Contraction-induced

These two mechanisms act separately, These two mechanisms act separately, but but additively additively using GLUT4using GLUT4

Thus, active insulin levels affect BG Thus, active insulin levels affect BG response to exercise by response to exercise by BG more BG more

Glucose Transport into MusclesGlucose Transport into Muscles

Wojtaszewski JF, et al., Acta Physiol Scand, 162(3): 351-8, 1998

Insulin Levels and BG ResponseInsulin Levels and BG Response

If active insulin levels are high, then BG If active insulin levels are high, then BG during extended activityduring extended activity

If insulin is deficient and ketones present, If insulin is deficient and ketones present, BG usually BG usually during exercise during exercise• Check for ketones if BG>250 mg/dl and Check for ketones if BG>250 mg/dl and

has been elevated for a whilehas been elevated for a while Exercise if ketones are none, but take Exercise if ketones are none, but take

corrective insulin (~50%) if >250 mg/dlcorrective insulin (~50%) if >250 mg/dl

Insulin Levels and BG ResponseInsulin Levels and BG Response

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Nondiabetic Controls

DM with Insulin

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Hormones and BG LevelsHormones and BG Levels

Some insulin is needed to moderate the Some insulin is needed to moderate the effects of glucose-raising hormones: effects of glucose-raising hormones: • Adrenaline and noradrenalineAdrenaline and noradrenaline• Glucagon, cortisol, and growth hormoneGlucagon, cortisol, and growth hormone

Cortisol and GH are higher during Cortisol and GH are higher during morning exercise (insulin resistance)morning exercise (insulin resistance)

Hormone release is intensity-dependent Hormone release is intensity-dependent (more adrenaline at higher workloads)(more adrenaline at higher workloads)

High Adrenaline Activities High Adrenaline Activities BG BG

Sports w/ intense “bursts”Sports w/ intense “bursts” Sprinting of any typeSprinting of any type Heavy weight liftingHeavy weight lifting Scary activities (e.g.,hang Scary activities (e.g.,hang

gliding or downhill skiing)gliding or downhill skiing) Intense competition Intense competition

(mental stress)(mental stress)

Endurance Exercise EffectsEndurance Exercise Effects

Extended exercise usually results in Extended exercise usually results in BG BG levels if any insulin “on board”levels if any insulin “on board”

Pre-exercise, short- or rapid-acting insulin Pre-exercise, short- or rapid-acting insulin doses will likely need to be lowereddoses will likely need to be lowered

BG likely BG likely after activity, with less insulin after activity, with less insulin needed in post-exercise period needed in post-exercise period insulin action during muscle glycogen insulin action during muscle glycogen

repletionrepletion

Balancing Exercise Blood Balancing Exercise Blood SugarsSugars

Exercise

Diet Medication

Exercise

Diet Medication

DiabetesTherapy

Challenges with Busy KidsChallenges with Busy Kids

Insulin doses and diet must match Insulin doses and diet must match precisely with exercise to avoid hyposprecisely with exercise to avoid hypos

Risk of hypoglycemia is higher both Risk of hypoglycemia is higher both during and following exerciseduring and following exercise

May be no improvement in overall BG May be no improvement in overall BG control in active kids w/o appropriate control in active kids w/o appropriate changes in diet and/or insulin doseschanges in diet and/or insulin doses

Regimen Changes for ExerciseRegimen Changes for Exercise

Increase carbohydrate intake for the Increase carbohydrate intake for the activity to prevent hyposactivity to prevent hypos

Adjust insulin doses before, during, and Adjust insulin doses before, during, and after activitiesafter activities

Try to prevent acute and delayed-onset Try to prevent acute and delayed-onset hypoglycemia, which can occur for up to hypoglycemia, which can occur for up to 48 hours after exercise48 hours after exercise

Predicting Glycemic ResponsesPredicting Glycemic Responses

Checking BG before, Checking BG before, often during, & after often during, & after exercise is exercise is key key to to learning BG responseslearning BG responses

BG levels during usual BG levels during usual activities can become activities can become somewhat predictable somewhat predictable & a pattern established& a pattern established

Factors Affecting BG ResponseFactors Affecting BG Response

Exercise intensity, duration, and type Exercise intensity, duration, and type Carbohydrate supplementationCarbohydrate supplementation Initial blood glucose levels Initial blood glucose levels Insulin dose Insulin dose before and/or during before and/or during

exercise and insulin peak timesexercise and insulin peak times Training effects on fuel useTraining effects on fuel use Timing of exercise boutTiming of exercise bout Other factors affecting BGOther factors affecting BG

Exercise IntensityExercise Intensity

Exercise IntensityExercise Intensity

Competitive events may be shorter, but Competitive events may be shorter, but much more intense than practices much more intense than practices

Greater release of glucose-raising Greater release of glucose-raising hormones causes BG to hormones causes BG to less less

Mental stress of competition alone can Mental stress of competition alone can levels of hormones as welllevels of hormones as well

Extra insulin may be needed after Extra insulin may be needed after competition to bring blood glucose downcompetition to bring blood glucose down

Exercise DurationExercise Duration

Exercise DurationExercise Duration

The longer an activity lasts, the greater The longer an activity lasts, the greater glucose-lowering effect it can haveglucose-lowering effect it can have

Rate of muscle glycogen use Rate of muscle glycogen use with with increasing exercise intensityincreasing exercise intensity

Longer duration at same intensity will Longer duration at same intensity will result in greater muscle glycogen useresult in greater muscle glycogen use

Greater glycogen depletion will cause Greater glycogen depletion will cause reliance on BG usereliance on BG use

Exercise TypeExercise Type

Exercise TypeExercise Type

Aerobic vs. anaerobic activities – is Aerobic vs. anaerobic activities – is there a metabolic difference?there a metabolic difference?• Blood glucose easier to maintain Blood glucose easier to maintain

during short, intense exerciseduring short, intense exercise• Longer duration activities generally Longer duration activities generally

necessitate greater regimen changesnecessitate greater regimen changes• Increased muscle mass improves Increased muscle mass improves

insulin sensitivity overallinsulin sensitivity overall

Intermittent High Intensity ExIntermittent High Intensity Ex

Guelfi KJ, et al., Diab. Care, 28(6): 1289-1294, 2005

4 second sprints every 2 minutes during 30 min mod (~40%) exercise

Carbohydrate Intake (Grams)Carbohydrate Intake (Grams)

ExerciseExerciseDurationDuration

Exercise Exercise IntensityIntensity

BG <100BG <100 BG 100-BG 100-150150

BG 150-BG 150-200200

BG BG >200>200

LowLow 5-105-10 0-100-10 NoneNone NoneNone

3030 minmin Mod.Mod. 10-2510-25 10-2010-20 5-155-15 0-100-10

HighHigh 15-3515-35 15-3015-30 10-2510-25 5-205-20

LowLow 10-1510-15 10-1510-15 5-105-10 0-50-5

60 min60 min Mod.Mod. 20-5020-50 15-4015-40 10-3010-30 5-155-15

HighHigh 30-4530-45 25-4025-40 20-3520-35 15-3015-30

Adapted from Colberg, S. The Diabetic Athlete, 2001

General Snacking GuidelinesGeneral Snacking Guidelines

Begin carb intake Begin carb intake priorprior to exercise to to exercise to prevent hyposprevent hypos

Adjust quantity based on pre-exercise Adjust quantity based on pre-exercise BG levels (none may be needed)BG levels (none may be needed)

Plan on snacking more when active Plan on snacking more when active insulin levels are higherinsulin levels are higher

Snack hourly during prolonged exercise Snack hourly during prolonged exercise to provide alternate carbs (besides BG)to provide alternate carbs (besides BG)

Carbs to Prevent & Treat HyposCarbs to Prevent & Treat Hypos

Best carbs for exercise: glucose tablets Best carbs for exercise: glucose tablets or gels, sugary candy, regular soft or gels, sugary candy, regular soft drinks, sports drinks, diluted juice, skim drinks, sports drinks, diluted juice, skim milk, power bars, pretzels, dry cereal, milk, power bars, pretzels, dry cereal, crackerscrackers

Do Do notnot consume: chocolate, donuts, consume: chocolate, donuts, potato chips, most candy bars, fat-laden potato chips, most candy bars, fat-laden cookies, high-fat dairy products, etc.cookies, high-fat dairy products, etc.

Carb Intake ExamplesCarb Intake Examples

*Soccer*Soccer: A pump user drinks sports : A pump user drinks sports drinks during practices, consuming 15-drinks during practices, consuming 15-30 gm of carbs per hour (insulin 30 gm of carbs per hour (insulin ))

Weight trainingWeight training: An NPH user eats 15 : An NPH user eats 15 grams of carbs only if BG grams of carbs only if BG 85 to start; 85 to start; another eats a higher-fat bedtime snackanother eats a higher-fat bedtime snack

SwimmingSwimming: For an AM swim before any : For an AM swim before any insulin, a Lantus user drinks a regular insulin, a Lantus user drinks a regular soda to soda to his BG to 225 mg/dl his BG to 225 mg/dl

Effect of Active Insulin LevelsEffect of Active Insulin Levels

Exercise Exercise Plasma Plasma InsulinInsulin

Liver Liver Glucose Glucose OutputOutput

Muscle Muscle Glucose Glucose UptakeUptake

Resulting Resulting Blood Blood

GlucoseGlucose

Normal Normal LevelLevel

Markedly Markedly DecreasedDecreased

Above Above NormalNormal

Adapted from Colberg, S. The Diabetic Athlete, 2001

Peak & Action of Various InsulinsPeak & Action of Various Insulins

Rapid-acting insulin analogs Rapid-acting insulin analogs (Humalog, Novolog, Apidra): (Humalog, Novolog, Apidra): peak in 1-2 hrspeak in 1-2 hrs

Short-acting Regular: Short-acting Regular: 2-3 hrs2-3 hrs Intermediate-acting (NPH): Intermediate-acting (NPH):

peak in 4-6 hrspeak in 4-6 hrs Long-acting, basal (Lantus, Long-acting, basal (Lantus,

Detemir, UL): Detemir, UL): mild or no peakmild or no peak

Insulin Insulin for Exercise Timing for Exercise Timing

For pre-meal exercise when insulin For pre-meal exercise when insulin levels low, little or no insulin levels low, little or no insulin needed needed

For exercise done 1-2 hours post-meal, For exercise done 1-2 hours post-meal, short/rapid insulin may need to be short/rapid insulin may need to be

Insulin should be Insulin should be for exercise done for exercise done during insulin peak timesduring insulin peak times

Basal insulin or pump basal rate may be Basal insulin or pump basal rate may be prior to and during extended exercise prior to and during extended exercise

General Insulin General Insulin for Exercise for ExerciseDurationDuration Low Low

IntensityIntensityModerate Moderate IntensityIntensity

High High IntensityIntensity

30 min30 min NoneNone 10-20%10-20% 10-30%10-30%

60 min60 min 10-20%10-20% 20-40%20-40% 30-60%30-60%

90 min90 min 15-30%15-30% 30-55%30-55% 45-75%45-75%

120 min120 min 20-40%20-40% 40-70%40-70% 60-90%60-90%

180 min180 min 30-60%30-60% 60-90%60-90% 75-100%75-100%

Adapted from Colberg, S. The Diabetic Athlete, 2001

Adjustments by Insulin TypeAdjustments by Insulin Type

Meal Boluses:Meal Boluses:• Low intensity Low intensity

cardio cardio 25% 25%• Moderate cardio Moderate cardio

33% 33%• High intensity High intensity

cardio cardio 50% 50%• Short/intense Short/intense

0%, plus bolus 0%, plus bolus afterwardsafterwards

Basal:Basal:• Pump: Pump: basal rate basal rate

by 50% starting 1 by 50% starting 1 hr prior, orhr prior, or

• Reconnect hourly Reconnect hourly to give 50% of to give 50% of usual basal rateusual basal rate

• Prior to prolonged Prior to prolonged ex ex injected basal injected basal up to 25%up to 25%

Insulin Reduction ExamplesInsulin Reduction Examples

*Soccer*Soccer: A pump user disconnects his : A pump user disconnects his pump during practices and pump during practices and pre-ex pre-ex meal Humalog by 3 units (carbs meal Humalog by 3 units (carbs ))

Weight trainingWeight training: A Lantus user takes no : A Lantus user takes no Humalog within 2 hrs of weight trainingHumalog within 2 hrs of weight training

SwimmingSwimming: During swim team season, a : During swim team season, a Lantus user decreases her total basal Lantus user decreases her total basal dose by 1/3 dose by 1/3

Training EffectsTraining Effects

Training Training BG use BG use and and fat use fat use

Thus, less muscle Thus, less muscle glycogen used after glycogen used after 2-3 weeks of training2-3 weeks of training

Need to Need to absolute absolute exercise intensity for exercise intensity for same effect same effect

Other Training AdjustmentsOther Training Adjustments

Regular exercise improves BG control Regular exercise improves BG control by increasing insulin sensitivityby increasing insulin sensitivity

Lower insulin doses may be needed Lower insulin doses may be needed overall with consistent trainingoverall with consistent training

Lesser carbohydrate intake may be Lesser carbohydrate intake may be needed for the training activityneeded for the training activity

Training effects on BG are specific to Training effects on BG are specific to the activity (with little carryover)the activity (with little carryover)

Timing of ExerciseTiming of Exercise

Cortisol and growth Cortisol and growth hormone higher in hormone higher in AM, AM, insulin action insulin action

Similar exercise done Similar exercise done later in the day (even later in the day (even post-breakfast) post-breakfast) BG BG moremore

Other FactorsOther Factors

Poor BG control Poor BG control insulin actioninsulin action

Physical/mental stress Physical/mental stress can can insulin action insulin action

Insulin action Insulin action during during 22ndnd half of menstrual half of menstrual cycle in teens/womencycle in teens/women

Environmental Environmental conditions (hot/cold)conditions (hot/cold)

Exercise PrecautionsExercise Precautions

Prevention of Acute HypoglycemiaPrevention of Acute Hypoglycemia

Hypoglycemia (BG < 65 mg/dl) is the most Hypoglycemia (BG < 65 mg/dl) is the most immediate risk during and after exerciseimmediate risk during and after exercise

Monitor glucose levels; avoid lows with Monitor glucose levels; avoid lows with preventive, corrective regimen changespreventive, corrective regimen changes

Access to simple carbs is essential for the Access to simple carbs is essential for the rapid treatment of hyposrapid treatment of hypos

Glucagon emergency kits should also be Glucagon emergency kits should also be available, especially for longer activitiesavailable, especially for longer activities

Most common following long duration or Most common following long duration or repeated bouts of high-intensity exerciserepeated bouts of high-intensity exercise

Caused by combination of enhanced Caused by combination of enhanced insulin action & muscle glycogen repletioninsulin action & muscle glycogen repletion

May occur up to 24-48 hours afterwards, May occur up to 24-48 hours afterwards, but 6-12 hours most commonbut 6-12 hours most common

May be prevented by May be prevented by insulin doses insulin doses and/or and/or food intake food intake

Prevention of Delayed-Onset HypoPrevention of Delayed-Onset Hypo

Prevention of Delayed-Onset HypoPrevention of Delayed-Onset Hypo

Hernandez JM, et al., Med Sci Sports Exerc, 32(5): 904-910, 2000

10-second Sprint at Exercise End10-second Sprint at Exercise End

Bussau VA, et al., Diab. Care, 29(3): 601-606, 2006

Other Hypoglycemia RisksOther Hypoglycemia Risks

Prior hypoglycemia (day before) of 70 Prior hypoglycemia (day before) of 70 mg/dl or less can blunt hormone release mg/dl or less can blunt hormone release during mod ex and during mod ex and risk of ex hypo risk of ex hypo

Hormonal exercise responses more Hormonal exercise responses more blunted in males than femalesblunted in males than females

Likewise, prior (day before) exercise Likewise, prior (day before) exercise (prolonged low to moderate) can blunt (prolonged low to moderate) can blunt next day responses to hypoglycemianext day responses to hypoglycemia

Galassetti, Sandoval, et al., Diab, AJP, 2004, 2006

Prevention of HyperglycemiaPrevention of Hyperglycemia

Hyperglycemia can acutely result from Hyperglycemia can acutely result from intense activities, or it can be worsened if intense activities, or it can be worsened if metabolic control is poor before exercisemetabolic control is poor before exercise

Avoid exercising if fasting glucose levels Avoid exercising if fasting glucose levels are >250 mg/dl with ketosis present are >250 mg/dl with ketosis present (indicative of insulin deficiency)(indicative of insulin deficiency)

Use caution if glucose levels are >300 Use caution if glucose levels are >300 mg/dl, and no ketosis is presentmg/dl, and no ketosis is present

ADA/ACSM Position Statement on Diabetes Mellitus and Exercise, Diab. Care, 27(1): S58-62, 2004

Prevention of DehydrationPrevention of Dehydration

Prevention of DehydrationPrevention of Dehydration

Hyperglycemia Hyperglycemia risk, but 1-2% of body risk, but 1-2% of body fluids already lost when thirstyfluids already lost when thirsty

Dehydration can Dehydration can BG readings as well BG readings as well (( blood volume blood volume BG concentration) BG concentration)

Hydrate with cool, plain water before & Hydrate with cool, plain water before & during activities, but don’t overdo itduring activities, but don’t overdo it

I full mouthful = about 1 oz. of fluidI full mouthful = about 1 oz. of fluid Use diluted fruit juices or sports drinksUse diluted fruit juices or sports drinks

Keys to Optimal PerformanceKeys to Optimal Performance

Keys to Optimal PerformanceKeys to Optimal Performance

Glycemic balance at all times is Glycemic balance at all times is key key to to optimizing exercise performanceoptimizing exercise performance

Monitor blood Monitor blood glucose frequentlyglucose frequently

Make diet and/or Make diet and/or insulin changes to insulin changes to keep BG as close to keep BG as close to normal as possiblenormal as possible

Keys to Optimal PerformanceKeys to Optimal Performance

Consume extra rapidly-absorbed carbs Consume extra rapidly-absorbed carbs during exercise to prevent hypoglycemiaduring exercise to prevent hypoglycemia

Low BG causes early fatigue and poor performance

Elevated insulin levels during exercise risk

Keys to Optimal PerformanceKeys to Optimal Performance

Consume carbs for 2-3 hours post-exercise Consume carbs for 2-3 hours post-exercise to rapidly restore muscle glycogento rapidly restore muscle glycogen

Take extra insulin as needed to cover rise in BG levels

Glycogen repletion risk of delayed-onset hypoglycemia

Keys to Optimal PerformanceKeys to Optimal Performance

Consume adequate fluids to prevent and Consume adequate fluids to prevent and correct dehydration (esp. if hyperglycemic)correct dehydration (esp. if hyperglycemic)

Dehydration performance

Elevated BG risk of dehydration

Dehydration can also BG readings

Keys to Optimal PerformanceKeys to Optimal Performance

Increase muscle mass to minimize Increase muscle mass to minimize insulin needs overallinsulin needs overall

Muscle acts as a glucose “sink”

Lower insulin requirements leave less room for error in insulin doses

ConclusionsConclusions

Exercise Your Right to Be ActiveExercise Your Right to Be Active

High level, even elite/Olympic, athletic High level, even elite/Olympic, athletic endeavors are possible w/ type 1 diabetesendeavors are possible w/ type 1 diabetes

Diabetic exercisers must be in good Diabetic exercisers must be in good control of BG levels to perform optimallycontrol of BG levels to perform optimally

Balancing carbohydrate intake with Balancing carbohydrate intake with exercise use is key to maintain BG controlexercise use is key to maintain BG control

Insulin doses usually have to be lowered Insulin doses usually have to be lowered for prolonged or frequent training as wellfor prolonged or frequent training as well

Gold Medal Dreams Are Still Gold Medal Dreams Are Still Possible With Type 1 Diabetes!Possible With Type 1 Diabetes!

More Activity-Specific InformationMore Activity-Specific Information

Sheri Colberg, PhD

Human Kinetics (Champaign, IL)

2001 (261 pages)

Over 85 sports and activities included

www.SheriColberg.com