sheri r. colberg, ph.d. old dominion university norfolk, virginia exercise & busy kids –...
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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
DM lacking Insulin
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