Current Research in
Type 1 Diabetes and
Exercise
Jane Yardley
Supported by:
Canadian Diabetes Association
Ottawa Health Research Institute
Preliminaries
• Please ask questions at any time about
anything that is unclear to you
• There will be props – you can ask about them
too
• I like to share (references, tables, files,
contact information – if you want it, please
ask me for it!)
Overview
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Meet the Researchers
Type 1 Diabetes: the Metabolism Basics
Exercise studies in type 1 diabetes
On-going research in type 1 diabetes and
physical activity
• The Role of New Technologies in Diabetes
Research
Important Names and Faces
Dr. Ronald Sigal MD, MPH, FRCPC
Dr. Ron Sigal (University of Calgary)
– Clinical medicine, teaching and research
– 1996-2006
• Senior Scientist (OHRI)
• Medical Director (Ottawa Hospital Diabetes
Clinic)
– Active member of CDA
– Diabetes and exercise randomized trials
– ADA and CDA guidelines for physical activity
Dr. Glen Kenny BSc, MSc, PhD
Dr. Glen Kenny (University of Ottawa)
– Professor, University Research Chair
– Over 100 peer-reviewed publications
– Physical activity (diabetes)
– Health and safety of workers (hostile
environments)
– Holds research funding from:
Jane Yardley BSc, MSc, PhD (a.b.d)
About me….
• B.Sc. in Biochemistry from Mount Allison
University (2000)
• M.Sc. in Evolutionary Anthropology from
University College London, UK (2001)
• PhD Candidate in Population Health at the
University of Ottawa
• Self-proclaimed “geeky jock”
Type 1 diabetes mellitus
• Insulin-producing β cells of the pancreas are
targeted by the immune system
• insulin secretion becomes impossible
• external sources of insulin become necessary
to maintain blood glucose control
• Can result in chronic hyperglycemia (high
blood glucose) with serious long-term health
problems
Management of Type 1 Diabetes
Main tools of treatment include:
1) Diet
2) Insulin
3) Physical Activity
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www.drjump.com/
i.ehow.com/images/GlobalPhoto
Diet
www.how-to-draw-cartoons-online.com
• Eat three meals a day at regular times
• Meals should be spaced no more than 6 hours apart
• Limit intake of sugars and sweets
(pop, desserts, candy, etc.)
• Limit intake of high fat foods
• Be sure to include high fibre foods
(whole grain breads/cereals, dried
beans/peas, brown rice, vegetables, fruits etc.)
• Choose lower fat sources of protein (fish, lean meats,
low fat cheeses)
• Drink plenty of water
Insulin
• a.k.a. “The Anabolic Queen”
• Promotes energy storage by
stimulating glucose uptake into
the body’s cells
• Glucose is then used for:
– Lipid synthesis
– Protein synthesis
– Glycogen synthesis
Insulin
How it works:
• Glucose is too big to diffuse across cell membranes
• Transport proteins (GLUT proteins) are necessary
• Muscle, fat, and heart cells use a very specific type of
transporter (GLUT4)
• Glut4 transporters are activated by insulin
Insulin Activation of Glut-4
http://courses.cm.utexas.edu/jrobertus/ch339k
Insulin
www.life-enhancement.com
• Naturally produced insulin
– Made by the β-cells of the pancreas
– Has a half-life of about 5 minutes
• Synthetic insulin
– Variety of delivery methods (pump, injection, etc.)
– Different durations from very short acting (0.5 to 2
hours) to long acting (up to 18 hours duration)
– Often necessary to combine more than one type
The Pancreas & Blood Glucose Control
Non insulin-mediated glucose uptake
• In certain situations, some cells in the body will take
up glucose without the presence of insulin
• When muscles twitch (generally through physical
activity), calcium ions are released
• Calcium stimulates the Glut-4 receptors on certain
cells (mostly skeletal muscle)
• Exercise allows glucose to be taken into the cells
without insulin being present, decreasing blood
glucose
Main Categories of exercise
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• Aerobic exercise
– Repeated and continuous movement of the
same large muscle groups
– Activity lasts an extended period of time
• Jogging
• walking
• swimming
• cycling
• etc.
Main Categories of exercise
• Anaerobic exercise
– Powerful bursts of activity requiring large
amounts of energy input but sustained for short
periods of time
– Activities include:
• Sprinting
• Weight lifting
• Plyometrics
• etc
www.personaltrainingprograms.com
The chronic effects of aerobic activity
in type 1 diabetes
http://images.inmagine.com/
• Measured glycemic control
by glycosylated hemoglobin
(HbA1c)
• Intervention studies have
shown mixed results
Chronic effects of aerobic exercise
Chronic effects of aerobic exercise
Why such inconsistent outcomes?
• In theory, physical activity should lower blood
glucose, and in the long run HbA1c
• Failure to improve HbA1c may lie in study design:
– Inadequate study duration
– Inadequate exercise frequency and/or intensity
– Low compliance rates
– Lack of supervised exercise sessions
– Excessive increase in caloric intake
– Excessive decrease in insulin intake
Acute Effects of Aerobic Exercise
Moderate Aerobic Exercise
(non-diabetic)
– Glucose uptake ↑↑
– Blood glucose ↓
– Insulin ↓, glucagon ↑
– Glucose and lipids released
– catecholamines ↑ (slightly)
– hepatic glucose production ↑
– Blood glucose ↑↑
– EUGLYCEMIA MAINTAINED
http://www.skaneatelessuites.com
Acute Effects of Aerobic Exercise
http://www.skaneatelessuites.com
Moderate Aerobic Exercise (Type 1
diabetes)
– Glucose uptake ↑↑
– Blood glucose ↓
– Insulin ↔, glucagon ↑
– Lower glucose and lipid release
– Catecholamines ↑/↔
– Hepatic glucose production ↔
– Blood glucose ↓↓
– HYPOGLYCEMIA
The chronic effects of physical
activity in type 1 diabetes
www.answers.com
Studies involving resistance
exercise, either on its own or
in combination with aerobic
exercise have generally had
positive outcomes
Studies Involving Resistance Exercise
in Type 1 Diabetes
Studies Involving Resistance Exercise
in Type 1 Diabetes
• Resistance exercise, whether on its own or combined
with aerobic exercise, seems to be beneficial for
glycemic control
• Why?
– Different hormonal reaction to high intensity
exercise
– Different hormones = different fuel source
Acute Effects of Anaerobic Exercise
• Non-diabetic individuals
– Catecholamines ↑↑↑↑
– Hepatic glucose production ↑↑↑↑
– Glucose uptake ↑↑
– Blood glucose ↑↑↑
– Insulin ↑ upon exercise completion
– Blood glucose ↓↓
– EUGLYCEMIA
Acute Effects of Anaerobic Exercise
• Type 1 diabetic Individuals
– Catecholamines ↑↑↑↑
– Hepatic glucose production ↑↑↑↑
– Glucose uptake ↑↑
– Blood glucose ↑↑↑
– Post-exercise Insulin production ↔
– Blood glucose ↑↑↑
– HYPERGLYCEMIA
Acute effects of Anaerobic Exercise
20 min. of aerobic activity
followed by a 10 sec. sprint
Bussau VA, Ferreira LD, Jones TW, Fournier PA.
Diabetes Care 2006;29(3):601-6.
Acute effects of Anaerobic Exercise
30 minutes of aerobic activity vs. 30 minutes of aerobic
activity with 4 second, all-out sprints every 2 minutes
Guelfi KJ, Jones TW, Fournier PA. Diabetes Care 2005;28(6):1289-94.
Resistance Exercise in Non-diabetic
individuals
6 X 10 reps of squats (80% max) vs resting control
French DN, et al. J Appl Physiol 2007;102(1):94-102.
On-Going Research
• Two large studies taking place in Ottawa examining
the effects of resistance exercise in type 1 diabetes
• T1-DARE – Type 1 Diabetes Aerobic and Resistance
Exercise
• READI - Resistance Exercise in Already Active
Diabetic Individuals
T1-DARE
• Examining the chronic effects of different exercise
programs on HbA1c in type 1 diabetic subjects
• Sedentary type 1 diabetic subjects randomized to
four different supervised training programs:
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Aerobic only
Resistance only
Aerobic and resistance
Control
READI
• Examining the effects of resistance exercise on type 1
diabetic individuals who are already aerobically active
• Subjects randomized to one of two groups:
– Resistance training*
– Control*
(*aerobic activities maintained in both groups)
Acute Effects of Aerobic and Resistance
exercise on Blood Glucose
• Recruiting participants who have completed T1-DARE or READI
OR who are already physically active
• Looking at blood glucose during and in the 24 hours after an
exercise session
• Also looking at how exercise order affects blood glucose
• 5 different exercise tests
– 1. Resting control
– 2. Aerobic exercise
– 3. Resistance exercise
– 4. Aerobic and resistance exercise
– 5. Resistance and aerobic exercise
Hypotheses
• Aerobic exercise will result in:
– Lower blood glucose and more hypoglycemia
• Resistance exercise will result in:
– Higher blood glucose and mild hyperglycemia
• Combined aerobic and resistance exercise sessions will:
– More time spent in euglycemia (compared to single
modality exercise sessions)
New Research Technologies
Continuous Glucose Monitoring
System (CGMS)
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Tiny, flexible sensor
Sterile, disposable
Inserted just under the skin
24 to 72-hour usable life
Sends measurement
signal to monitor every
10 seconds
• Measures glucose values
within the range of 2.2-22.2
mmol/L
New Research Technologies
New Research Technologies
New Research Technologies
Even Newer Technologies
The glucose sensor is placed
under the skin where it
measures glucose levels in the
interstitial tissue.
The CGMS® iPro™ Digital
Recorder attaches to the
glucose sensor. It continuously
records and stores the ISIG
signals from the glucose sensor.
The Sen-serter® insertion
device is used to insert the
glucose sensor
The Charger charges
the recorder. It is batterypowered, and requires one
AAA battery.
Questions
Contact Information
Jane Yardley
janeyardley@hotmail.com
(613) 562-5800 ext. 4948
Janet Richardson (T1-DARE and READI studies)
jarichardson@ohri.ca
(613) 738-8400 ext. 81965