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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.

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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

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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

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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

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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

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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

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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.

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Training Day: Indy Light Series Race Day: Indy Light Series

Moving Up to IndyCar Carb Solution

PreRace Meal

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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.

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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