Transcript Exercise & Busy Kids - Children with Diabetes

Exercise & Busy Kids –
Preventing and Managing
Hypos
Sheri R. Colberg, Ph.D.
Old Dominion University
Norfolk, Virginia
“Diabetic Athlete” - An Oxymoron?


No! There are many diabetic athletes
worldwide competing even at elite levels
•
Chris Dudley (NBA basketball)
•
Jay Leeuwenburg (NFL football)
•
Kris Freeman (U.S. XC ski team)
•
Gary Hall, Jr. (Olympic swimming)
Many others have run marathons, done
triathlons, and competed in every type
of sport and physical activity
Goals of Exercise Management
Prevention of hypoglycemia during and
after any physical activity
 Rapid management of hypos caused by
exercise
 Prevention of hyperglycemia and DKA
 Optimal athletic performance

Effects of Low BG on Exercise
Early, rapidonset fatigue
 Potential loss
of coordination
 Reduced
endurance
 Decreased
performance

What Is Optimal BG for Exercise?
Varies, but most athletes perform best
with BG levels of 80-180
 Some 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
of Exercise on BG Control
Exercise Energy Systems
The way energy is produced and used
during an activity affects BG use
 Three distinct energy systems exist:
• Immediate (phosphates, or ATP-CP)
• Lactic acid system (rapid glycolysis)
• Aerobic (oxygen)
 Their use is a continuum and depends on
exercise type, duration, and intensity

Exercise Energy Systems
Contribution of System (%)
100
80
ATP-CP
Glycolysis
60
Aerobic
40
20
0
10 sec
30 sec
1 min Time
3 min
5 min
Fuel Use during Exercise

For most exercise, carbs are main fuel:
glycogen (~80%), BG (20%)
Romijn JA, et al., JAP, 88(5): 1707-1714, 2000
Fuel Use during Exercise
BG uptake into muscles occurs 2 ways:
• Insulin-mediated
• Contraction-induced
 These two mechanisms act separately,
but additively using GLUT4
 Thus, active insulin levels affect BG
response to exercise by  BG more

Glucose Transport into Muscles
Wojtaszewski JF, et al., Acta Physiol Scand, 162(3): 351-8, 1998
Insulin Levels and BG Response
If active insulin levels are high, then BG 
during extended activity
 If insulin is deficient and ketones present,
BG usually  during exercise
• Check for ketones if BG>250 mg/dl and
has been elevated for a while
 Exercise if ketones are none, but take
corrective insulin (~50%) if >250 mg/dl

Insulin Levels and BG Response
Blood Glucose (mg/dl)
400
DM lacking Insulin
350
300
250
DM with Insulin
200
150
100
Nondiabetic Controls
50
0
0
10
20
Time (min)
30
Hormones and BG Levels

Some insulin is needed to moderate the
effects of glucose-raising hormones:
•
Adrenaline and noradrenaline
•
Glucagon, cortisol, and growth hormone
Cortisol and GH are higher during
morning exercise (insulin resistance)
 Hormone release is intensity-dependent
(more adrenaline at higher workloads)

High Adrenaline Activities  BG
Sports w/ intense “bursts”
 Sprinting of any type
 Heavy weight lifting
 Scary activities (e.g.,hang
gliding or downhill skiing)
 Intense competition
(mental stress)

Endurance Exercise Effects
Extended exercise usually results in  BG
levels if any insulin “on board”
 Pre-exercise, short- or rapid-acting insulin
doses will likely need to be lowered
 BG likely  after activity, with less insulin
needed in post-exercise period
•  insulin action during muscle glycogen
repletion

Balancing Exercise Blood
Sugars
Exercise
Diabetes
Therapy
Diet
Medication
Challenges with Busy Kids
Insulin doses and diet must match
precisely with exercise to avoid hypos
 Risk of hypoglycemia is higher both
during and following exercise
 May be no improvement in overall BG
control in active kids w/o appropriate
changes in diet and/or insulin doses

Regimen Changes for Exercise
Increase carbohydrate intake for the
activity to prevent hypos
 Adjust insulin doses before, during, and
after activities
 Try to prevent acute and delayed-onset
hypoglycemia, which can occur for up to
48 hours after exercise

Predicting Glycemic Responses
Checking BG before,
often during, & after
exercise is key to
learning BG responses
 BG levels during usual
activities can become
somewhat predictable
& a pattern established

Factors Affecting BG Response
Exercise intensity, duration, and type
 Carbohydrate supplementation
 Initial blood glucose levels
 Insulin dose  before and/or during
exercise and insulin peak times
 Training effects on fuel use
 Timing of exercise bout
 Other factors affecting BG

Exercise Intensity
Exercise Intensity
Competitive events may be shorter, but
much more intense than practices
 Greater release of glucose-raising
hormones causes BG to  less
 Mental stress of competition alone can 
levels of hormones as well
 Extra insulin may be needed after
competition to bring blood glucose down

Exercise Duration
Exercise Duration
The longer an activity lasts, the greater
glucose-lowering effect it can have
 Rate of muscle glycogen use  with
increasing exercise intensity
 Longer duration at same intensity will
result in greater muscle glycogen use
 Greater glycogen depletion will cause 
reliance on BG use

Exercise Type
Exercise Type

Aerobic vs. anaerobic activities – is
there a metabolic difference?
• Blood glucose easier to maintain
during short, intense exercise
• Longer duration activities generally
necessitate greater regimen changes
• Increased muscle mass improves
insulin sensitivity overall
Intermittent High Intensity Ex
4 second
sprints
every 2
minutes
during 30
min mod
(~40%)
exercise
Guelfi KJ, et al., Diab. Care, 28(6): 1289-1294, 2005
Carbohydrate Intake (Grams)
Exercise Exercise BG <100 BG 100- BG 150Duration Intensity
150
200
30 min
60 min
BG
>200
Low
5-10
0-10
None
None
Mod.
10-25
10-20
5-15
0-10
High
15-35
15-30
10-25
5-20
Low
10-15
10-15
5-10
0-5
Mod.
20-50
15-40
10-30
5-15
High
30-45
25-40
20-35
15-30
Adapted from Colberg, S. The Diabetic Athlete, 2001
General Snacking Guidelines
Begin carb intake prior to exercise to
prevent hypos
 Adjust quantity based on pre-exercise
BG levels (none may be needed)
 Plan on snacking more when active
insulin levels are higher
 Snack hourly during prolonged exercise
to provide alternate carbs (besides BG)

Carbs to Prevent & Treat Hypos
Best carbs for exercise: glucose tablets
or gels, sugary candy, regular soft
drinks, sports drinks, diluted juice, skim
milk, power bars, pretzels, dry cereal,
crackers
 Do not consume: chocolate, donuts,
potato chips, most candy bars, fat-laden
cookies, high-fat dairy products, etc.

Carb Intake Examples
*Soccer: A pump user drinks sports
drinks during practices, consuming 1530 gm of carbs per hour (insulin )
 Weight training: An NPH user eats 15
grams of carbs only if BG  85 to start;
another eats a higher-fat bedtime snack
 Swimming: For an AM swim before any
insulin, a Lantus user drinks a regular
soda to  his BG to 225 mg/dl

Effect of Active Insulin Levels
Exercise
Plasma
Insulin
Liver
Glucose
Output
Muscle
Glucose
Uptake
Resulting
Blood
Glucose
Normal
Level
Markedly
Decreased
Above
Normal
Adapted from Colberg, S. The Diabetic Athlete, 2001
Peak & Action of Various Insulins
Rapid-acting insulin analogs
(Humalog, Novolog, Apidra):
peak in 1-2 hrs
 Short-acting Regular: 2-3 hrs
 Intermediate-acting (NPH):
peak in 4-6 hrs
 Long-acting, basal (Lantus,
Detemir, UL): mild or no peak

Insulin  for Exercise Timing
For pre-meal exercise when insulin
levels low, little or no insulin  needed
 For exercise done 1-2 hours post-meal,
short/rapid insulin may need to be 
 Insulin should be  for exercise done
during insulin peak times
 Basal insulin or pump basal rate may be
 prior to and during extended exercise

General Insulin  for Exercise
Duration
Low
Intensity
Moderate
Intensity
High
Intensity
30 min
None
10-20%
10-30%
60 min
10-20%
20-40%
30-60%
90 min
15-30%
30-55%
45-75%
120 min
20-40%
40-70%
60-90%
180 min
30-60%
60-90%
75-100%
Adapted from Colberg, S. The Diabetic Athlete, 2001
Adjustments by Insulin Type

Meal Boluses:
•
•
•
•
Low intensity
cardio  25%
Moderate cardio
 33%
High intensity
cardio  50%
Short/intense 
0%, plus bolus
afterwards

Basal:
•
•
•
Pump:  basal rate
by 50% starting 1
hr prior, or
Reconnect hourly
to give 50% of
usual basal rate
Prior to prolonged
ex  injected basal
up to 25%
Insulin Reduction Examples
*Soccer: A pump user disconnects his
pump during practices and  pre-ex
meal Humalog by 3 units (carbs )
 Weight training: A Lantus user takes no
Humalog within 2 hrs of weight training
 Swimming: During swim team season, a
Lantus user decreases her total basal
dose by 1/3

Training Effects
Training  BG use
and  fat use
 Thus, less muscle
glycogen used after
2-3 weeks of training
 Need to  absolute
exercise intensity for
same effect

Other Training Adjustments
Regular exercise improves BG control
by increasing insulin sensitivity
 Lower insulin doses may be needed
overall with consistent training
 Lesser carbohydrate intake may be
needed for the training activity
 Training effects on BG are specific to
the activity (with little carryover)

Timing of Exercise
Cortisol and growth
hormone higher in
AM,  insulin action
 Similar exercise done
later in the day (even
post-breakfast)  BG
more

Other Factors
Poor BG control 
insulin action
 Physical/mental stress
can  insulin action
 Insulin action  during
2nd half of menstrual
cycle in teens/women
 Environmental
conditions (hot/cold)

Exercise Precautions
Prevention of Acute Hypoglycemia
Hypoglycemia (BG < 65 mg/dl) is the most
immediate risk during and after exercise
 Monitor glucose levels; avoid lows with
preventive, corrective regimen changes
 Access to simple carbs is essential for the
rapid treatment of hypos
 Glucagon emergency kits should also be
available, especially for longer activities

Prevention of Delayed-Onset Hypo
Most common following long duration or
repeated bouts of high-intensity exercise
 Caused by combination of enhanced
insulin action & muscle glycogen repletion
 May occur up to 24-48 hours afterwards,
but 6-12 hours most common
 May be prevented by  insulin doses
and/or  food intake

Prevention of Delayed-Onset Hypo
Hernandez JM, et al., Med Sci Sports Exerc, 32(5): 904-910, 2000
10-second Sprint at Exercise End
Bussau VA, et al., Diab. Care, 29(3): 601-606, 2006
Other Hypoglycemia Risks
Prior hypoglycemia (day before) of 70
mg/dl or less can blunt hormone release
during mod ex and  risk of ex hypo
 Hormonal exercise responses more
blunted in males than females
 Likewise, prior (day before) exercise
(prolonged low to moderate) can blunt
next day responses to hypoglycemia

Galassetti, Sandoval, et al., Diab, AJP, 2004, 2006
Prevention of Hyperglycemia
Hyperglycemia can acutely result from
intense activities, or it can be worsened if
metabolic control is poor before exercise
 Avoid exercising if fasting glucose levels
are >250 mg/dl with ketosis present
(indicative of insulin deficiency)
 Use caution if glucose levels are >300
mg/dl, and no ketosis is present

ADA/ACSM Position Statement on Diabetes Mellitus and Exercise,
Diab. Care, 27(1): S58-62, 2004
Prevention of Dehydration
Prevention of Dehydration
Hyperglycemia  risk, but 1-2% of body
fluids already lost when thirsty
 Dehydration can  BG readings as well
( blood volume  BG concentration)
 Hydrate with cool, plain water before &
during activities, but don’t overdo it
 I full mouthful = about 1 oz. of fluid
 Use diluted fruit juices or sports drinks

Keys to Optimal Performance
Keys to Optimal Performance

Glycemic balance at all times is key to
optimizing exercise performance
 Monitor blood
glucose frequently
 Make diet and/or
insulin changes to
keep BG as close to
normal as possible
Keys to Optimal Performance

Consume extra rapidly-absorbed carbs
during exercise to prevent hypoglycemia
 Low BG causes
early fatigue and
poor performance
 Elevated insulin
levels during
exercise  risk
Keys to Optimal Performance

Consume carbs for 2-3 hours post-exercise
to rapidly restore muscle glycogen
 Take extra insulin
as needed to cover
rise in BG levels
 Glycogen repletion
 risk of delayedonset hypoglycemia
Keys to Optimal Performance

Consume adequate fluids to prevent and
correct dehydration (esp. if hyperglycemic)
 Dehydration 
performance
 Elevated BG 
risk of dehydration
 Dehydration can
also  BG readings
Keys to Optimal Performance

Increase muscle mass to minimize
insulin needs overall
 Muscle acts as a
glucose “sink”
 Lower insulin
requirements leave
less room for error
in insulin doses
Conclusions
Exercise Your Right to Be Active
High level, even elite/Olympic, athletic
endeavors are possible w/ type 1 diabetes
 Diabetic exercisers must be in good
control of BG levels to perform optimally
 Balancing carbohydrate intake with
exercise use is key to maintain BG control
 Insulin doses usually have to be lowered
for prolonged or frequent training as well

Gold Medal Dreams Are Still
Possible With Type 1 Diabetes!
More Activity-Specific Information
Sheri Colberg, PhD
Human Kinetics
(Champaign, IL)
2001 (261 pages)
Over 85 sports and
activities included
www.SheriColberg.com