DIABETES AND EXERCISE PHYSIOLOGY - Internal Medicine · DIABETES AND EXERCISE PHYSIOLOGY Anne Peters, MD Medscape Professor, USC Keck School of Medicine Director, USC Clinical Diabetes
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6/5/2014
1
DIABETES AND EXERCISE
PHYSIOLOGY
Anne Peters, MD
Professor, USC Keck School of Medicine
Director, USC Clinical Diabetes Programs
Disclosure of Financial Relationships
Consultantship
Abbott Diabetes Care
BD
Janssen
Lilly
Medscape
Medtronic Minimed
NovoNordisk
Sanofi
Takeda
Speakers Bureau
BMS/AstraZeneca
NovoNordisk
Challenges for Athletes with Diabetes
• Varying workouts—type/duration/intensity
• Different responses to training vs competition
• Unpredictability
• Risk for hypoglycemia
• Impact of hyperglycemia on performance
• Physical factors (sweat/water/heat/cold)
• Everything else that impacts athletes without diabetes…
Exercise Physiology 101
• Muscles use glucose as primary energy source
initially—this comes from muscle glycogen stores
• Once these sources are depleted there is a balance
between glucose production (mostly from hepatic
glycogenolysis) and glucose uptake by exercising
muscle.
• Immediately post-exercise there is a rapid decrease in
catecholamines and increase in insulin levels with
restoration of muscle glycogen
Gallen IW et al. Diabetes, Obesity and Metabolism 13:130-136, 2011
The Problem
• Savanah wants to train for a 10 K. She starts to train.
• She tests her BG pre-exericse which is 105 mg/dl. Ate 35 g CHO.
No insulin. Waits to work out.
• 1 hour later BG = 240 mg/dl. Suspended pump. Four mile
walk/jog.
• 15 mins after exercise BG = 102 mg/dl. Ate 10 g CHO.
• 15 minutes later BG = 144 mg/dl. Ate 30 g CHO in a snack and
gave 3.4 units insulin. Time = 4 PM.
The Problem
• 6 pm (2 hours later) BG = 45 mg/dl. Ate 100 g CHO (she
notes: overate due to hunger/workout/poor choice).
• Waited for 30 mins and gave 8.1 units.
• 10 PM = 133 mg/dl.
• 11 PM = 46 mg/dl, felt nauseated, ate 30 g CHO.
• 11:15 PM = 59 mg/dl.
• 11:30 PM = 35 mg/dl. Ate 30 g CHO.
6/5/2014
2
The Problem
• Midnight BG = 90 mg/dl, 12:15 am = 88 mg/dl.
• Afraid to sleep. Suspends pump for 2 hours.
• 2:30 AM BG = 355 mg/dl. Suggested dose = 4.7 units. She
gave 3.5 units.
• 7 AM BG = 297 mg/dl. Suggested dose = 3.7 units, she gave
3.3 units.
• 10 AM BG = 66 mg/dl. 15 g CHO.
• 10:15 AM BG = 68 mg/dl. 30 g CHO.
• Noon = 110 mg/dl.
The Problem
• Total extra CHO due to lows = 230 g
• Total extra calories due to lows = 920
• Total impact on confidence = huge
Nondiabetic Athletes’ Fuel Focus: Carbs
• Providing adequate fuel to muscle
• May cycle carbohydrate intake during phases of
training
• Carbohydrate loading (3 days of a carbohydrate
intake of 8-12 g/kg/day or 70 – 85% of total caloric
intake with a taper in training) can double muscle
glycogen
• To replete glycogen stores: CHO intake of ~1.0–1.5
g/kg BW (0.5–0.7 g/lb) during the first 30 min after
exercise and every 2 h for 4–6 h.
Carbohydrate Requirements for Exercise
Training Load CHO recommendation
(g/kg/day)
Very Light Training 3-5
Moderate intensity for 1 hr/day 5-7
Mod to high intensity for 1-3 hr/day 7-10
Mod to high intensity for 4-5 hr/day 10-12
Gallen IW et al. Diabetes, Obesity and Metabolism 13:130-136, 2011
Typical Training Day Meal for Michael Phelps Muscle Glycogen and Training
Ryan M. Sports Nutrition for Endurance Athletes
Mu
scle
Gly
co
gen
Level
(mm
ol
kg
)
Time (Days)
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Barriers to Physical Activity Among Patients With
Type 1 Diabetes
CONCLUSION— Fear of hypoglycemia is the strongest
barrier to regular physical activity
Diabetes Care 31:2108–2109, 2008
Causes of Hypoglycemia During Exercise
• Inability to reduce basal insulin levels during exercise
• More rapid insulin absorption
• Inadequate carbohydrate intake
• Insulin sensitivity variable pre/during/post exercise
• Both acute and delayed (up to 24 hours)
hypoglycemia may occur
Biphasic Effect of Exercise on Glucose
Requirements in Adolescents with T1 DM Euglycemic Clamp Study
McMahon SK, Ferreira LD, Ratnam N, Davey RJ, Youngs LM, Davis EA,
Fournier PA, Jones TW. JCEM 92:963-968, 2007
Fat Free Chocolate Milk as Post-Exercise Drink
June 4, 2011 -- Fat-free chocolate milk beat out
carbohydrate sports drinks at helping to rebuild and refuel
muscles after exercise, researchers report. The combination of
carbohydrates and protein in low-fat chocolate milk appears
to be "just right" for refueling weary muscles, says William
Lunn, PhD, an exercise scientist at the University of
Connecticut.” It's not just a dessert item, but it's very healthy,
especially for endurance athletes.
WebMD
Fat Free Chocolate Milk as PostExercise Drink
• 8 male runners, ate a balanced diet for two weeks.
• At the end of each week, they took a fast paced, 45-min run.
• Following each run, the men drank either 16 ounces of fat-free
chocolate milk or 16 ounces of a CHO-only sports beverage
with the same number of calories.
• Post-exercise muscle biopsies showed increased skeletal muscle
protein synthesis after the milk drink, compared with the carb-
only beverage.
• Additionally, drinking fat-free chocolate milk led to a higher
concentration of glycogen, or muscle fuel, in muscles 30 and 60
minutes after exercise, compared with the sports drink.
• Findings were presented at the American College of Sports
Medicine.
Moderate Intensity Vs. Intermittent High Intensity
Exercise In Type 1 DM
Guelfi KJ, Jones TW,
Fournier. Diabetes
Care 28:1289-1294,
2005
6/5/2014
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Adjustments for Exercise
• Patients with type 1 diabetes on ultralente insulin
and preprandial lispro insulin were studied.
• 90 minute postprandial exercise for 30 - 60 minutes
at 25%, 50% and 75% VO2max was performed
• Insulin doses given at 100%, 50% or 25% of the
current dose of lispro (~1 unit/10 g CHO)
Diabetes Care 24:625-630, 2001
Results: One Example
-100
-50
0
50
100
Ch
an
ge
in g
lu f
rom
ba
seli
ne
(mg/d
l)
50% LP
100% LP
30 60 90 120 150 180 0
Exercise at
50% VO2max
for 30 min
Guidelines for the reduction in premeal RA dose
Exercise Intensity % Dose Reduction
(%VO2max) 30 min 60 min
exercise exercise
25 25 50
50 50 75
75 75 ---
Can technology help?
Available Technologies CGM: Dexcom Gen 4
6/5/2014
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The Value of Continuous Glucose Monitoring
Riddell Michael et al..Diabetes Tech Therap 13:2011
<90 mg/dl 90-108 mg/dl 109-124 mg/dl
Sensor Rate of Changed Guided CHO Algorithm
for Exercising Youth with T1DM
The Ideal
Delayed Hypoglycemia When It Works: Chicago Marathon
6/5/2014
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When It Doesn’t: Wildflower Triathalon The New Art of Diabetes Management
Why Not Race? Gary Hall: Learning About Swimming
Nutrition Gary Hall, Jr: Training Day 600 gm carbs
6/5/2014
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Gary Hall, Jr: Race Day Fit the Therapy to the Patient
Hypoglycemia in the 2010 Olympics Kris Freeman
Hypoglycemia in the 2010 Olympics Kris Freeman—basal rate = 2 units/hr
Kris Freeman Blog
Given the promising way the season started and the dismal way it
developed I am a serious contender for the most volatile and
inconsistent skier on the world cup. Recognizing this I am going
back to the drawing board on my diabetes care regimen. I
have already been fitted with the latest Dexcom continuous
glucose monitor and thus far it seems very promising…Over the
past two years I had such tunnel vision towards the Olympics
that I stopped integrating new developments in diabetes
treatment into my glucose management. I was more focused on
training. Clearly this was a mistake. I cannot fully utilize my
training when I have glucose issues.
March 2010
6/5/2014
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Kris Freeman Data
Since the Olympics I have been formulating a strategy for my
insulin dosing…I decided…to do 4-5 time-trials…I set my basal
insulin at my current rate which is .5 units per hour. I planned to
ski 30k with the first 20k at just above threshold with maximal
effort over the last 10k…My hypothesis was that my blood
glucose would remain constant for the first 20k and then rise
over the last 10k due to the anaerobic nature of a maximal
effort. To my surprise my glucose remained constant throughout
the effort. I fed an average of 10 ounces of Gatorade per 5
kilometers.
Kris Freeman Data
Throughout the test I also compared the data that my new CGM
gave me to the results I got from my Lifescan monitor...I skied
thee 7k loops followed by four 3k loops. I stopped at the end
of each loop for blood testing. Blog June
2010KM, Split, HR, CGM, BG, Lactate, Feed
Start 106, 1007km, 18.11, 146,
88, 105, 5.6, 10
oz14km, 17.30, 155, 84, 119, 6.7, 11
oz21km, 17.39, 152, 96, 107, 5.8, 5
oz24km, 7.59, 155, 89, 108, 9.0, 7
oz27km, 7.17, 156, 96, 112, 8.9, 12
oz30km, 7.36, 157, 100 100, 9.1, 12
oz33km, 7.21, 160, 105 125, 10.3
Kris Freeman Data
Racing with diabetes presents many challenges but
simply living on the road can be difficult as well. It is
well documented that I had some severe low blood
sugar while I was racing last year but to compound that I
was also having low sugar while at rest. It was not
uncommon for me to have sugars falling into the 50’s
during travel or while sleeping. Having low blood sugar
wastes adrenaline and leads to long term fatigue.
Nov 2010 blog http://blogs.fasterskier.com/krisfreeman/
Kris Freeman Data
Briefly, the new strategy is to frontload my insulin dose before
the race instead of during it. I take a 30 minute extended bolus
30 minutes prior to the start of the competition....In the past I
would give myself this dose directly before the start of the…The
first time I did this was at New Zealand Nationals…I took three
units 40 minutes prior to the start of the race. I finished with a
blood sugar of 240…my next race wasthe Whiteface Hill
climb. I took 4 units 35 minutes prior to the start. I had a good
race but my blood sugar control was terrible and very
disconcerting. I was at 350 and had a lactate of 12 to go along
with it. Clearly I had way under-dosed again.
Kris Freeman Data
Whiteface was supposed to be my last 15k max effort before
going to Finland but I decided I needed to test the new dosing
strategy one more time. This time I upped the dose to 6 units
and took it 30 minutes prior to start. The rocks on the bottom
half of the course were slick. About half way up I hit the
snowline and the footing actually improved. The trail was a nice
firm snowy bootpack. I finished up in the clouds to find that I
had run a new course record 35:16. That wasn’t the best news
of the day though. My bloodsugar was 105 at the top. I have
found the sweet spot so to say and just in time.
6/5/2014
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Training Day: Indy Light Series Race Day: Indy Light Series
Moving Up to IndyCar Carb Solution
PreRace Meal
6/5/2014
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When It Doesn’t
When It Doesn’t First Half Indy 2012
A Different Way to Measure Myself
Every fall. Harvest. A time to gather, I am gathering
myself together. I am preparing. I am readying myself for an
event. A race called “Stair Climb to the Top.” A big, boastful
name.
I do not know why I am challenging myself. Why am I
doing something so difficult? I need this justification to fill in a hole
of incompleteness. Of feeling inadequate. It is proof, my proof,
that I can defy my diabetes. I will outsmart it. I will challenge
every blood sugar level that I come across. I need something to
hold onto. A different way to measure myself.
A Different Way to Measure Myself
To get ready I practice 3 to 4 times a week for several
months. I find a set of weathered stairs cradled in a side of a
mountain in Santa Monica…The stairs never get easier. However,
with each practice I am closer to feeling better about myself.
Exercise makes gluocse control more of a challenge. High sugars
slow entry of glucose into muscle. The stair climb then feels like
torture.
The night before the race I am extremely careful about what
I eat. More cautious than normal. I awaken at 3 AM with a low
blood sugar. I can’t go back to sleep. I get up at 6:00 AM with a
BG = 63. Too low for exercise. I feel horrible, tired, jittery,
nauseated. I eat, inject insulin, shower, and talk myself into feeling
better because no matter what, I am going to do the stair climb.
6/5/2014
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A Different Way to Measure Myself
I drive to the race through fog and dim light. I am angry
that my body has let me down. A voice inside tells me that I am not
capable. With great force I break away from these thoughts and
tell myself over and over that I can do this.
I take another blood test. It reads 150. I am pleased. I
begin to relax a little about my blood sugar. I chat with the other
stair climbers.
An announcement states: “15 minutes to starting time.” Time for one last blood test. 158, still good. My doctor suggested
injecting two units of insulin just prior to the race because as the
adrenaline kicks in, the sugar rises. I do not trust her system. So I
inject half a unit and get in line. The building appears
extraordinarily high. I cannot do this. I must do this.
A Different Way to Measure Myself
I run through the balloon arch and begin the ascent…I
start a little too quickly…By the 25th floor I am in trouble. Only a
third of the way through and my legs are beginning to tighten. I
had passed five people but now others are passing me. I step
close to the handrail as others go by….
The stairwell is disorienting and dusty. I concentrate on
taking one step at a time. It is a large task. I had planned to
sprint to the top but I have nothing left in me. Then I hear loud
music and great cheering. The 74th and finally the 75th floor. Yes!
I’ve done it. I am outside, on the deck of the tallest building in Los
Angeles. In fresh air.
A Different Way to Measure Myself
But I feel rotten. I test my BG, which is 374. Diabetes had interfered.
The disease robbed me of feeling strong, healthy, and athletic. What a huge
disappointment! I feel fatigued and nauseated. My head aches. I drink more
water and inject 3 units of insulin. I can’t celebrate. Where’s my moment of joy?
Later, my daughter calls. “So Mom, how did you do?”
“Not great, “ I say. “I wanted to be faster. If I didn’t have diabetes I would
have done it so much better.”
To which my wise daughter replies, “If you didn’t have diabetes, you probably
wouldn’t have climbed the stairs at all.” She gathers me back together.
Whenever I drive east, towards downtown on a clear day in Los
Angeles, the Library Tower stands as a giant among the other buildings. Every
time I see that building I feel triumphant, knowing that for a brief moment I had
conquered the fear of the stairs and the craziness of diabetes. I have climbed to
the top. I have completed the task.
How to Adjust Insulin for Aerobic Exercise
½ Usual
Insulin Dose
Meal Before 15-30 gm
CHO if
<150
15-30 gm CHO q30
mins
30 – 60 gm
snack with ½
usual insulin
dose
Less
basal
over-
night
THANK YOU
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