exercise and type 1: lessons from a researcher and person with diabetes (pwd) michael c. riddell,...
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Exercise and Type 1:Lessons from a researcher and Person with Diabetes (PWD)
Michael C. Riddell, PhD. School of Kinesiology and Health Science, Muscle Health Research Centre, Physical Activity and Diabetes Unit, Faculty of Health
Objectives1. Explain briefly why exercise is so
important for our diabetes2. Provide an overview of the
physiology of exercise and diabetes3. Outline some pump and insulin
injection strategies to improve blood sugar control during (and after) exercise
4. Discuss the advantages and limitations of continuous glucose monitoring (CGM) for exercise
• Regular exercise/sports participation is associated with MAJOR health benefits for people with type 1:– Improved mental and physical health (if not sugar control)
– Enjoyment– Neuromuscular and cardiovascular development and fitness– Prevention from diabetes-related complications– Weight maintenance and conditioning– Enhanced insulin sensitivity– Increased independence later in life– Increased life expectancy (10 years)
Exercise, why bother?
Diabetes and exercise
• Common part of children's lives• Encouraged in diabetes• Benefits of exercise include
– Sense of well-being– Weight control– Limit rise in glucose after meals– Lowers heart rate and blood pressure– Lowers blood lipid levels
• Reduces cardio-vascular risk
• Hypoglycaemia
• Hyperglycaemia
• Ketones
BENEFITS RISKS
Exercise is however, a complex variable…
Glucose levels during an active day for an adolescent who does not
have diabetes
Euglycemia
Exercise and Diabetes-101
Have you ever wondered “why is it so darn hard to manage physical activity and type 1 diabetes?”
Why Exercise Management is Challenging
• We do different types of exercise
• We are afraid to develop hypoglycemia
• We all respond to exercise differently
• Even we don’t respond exactly the same way twice!
• We don’t make ANY adjustments for exercise
• The adjustments we are told to make don’t work
• It is impossible to perfectly match the insulin we take to what our bodies need
Exercise, Insulin and Glucose
Person without diabetes Person with diabetes
Insulin release Insulin “levels”
BG levels BG levels
Hyperglycemia and Exercise
Competitive events and/or high intensity exercisecan cause hyperglycemia
Competition
50% correction bolus
Exercise and Diabetes: Advanced
5-7mM
ExerciseInsulinfood
Balanced Blood Sugar
Increased by Decreased byInsulin
food
Blood Glucose Flux During Exercise in T1DM
Glycemic control remains a challenge… Exercise
causes major perturbation to glucose turnover…
• Frequent testing is essential• A pump can help
Physical Activity Levels and HbA1c (Type 1)
N= 296 children, adolescents, and young adults with type 1 diabetes
Galler et al., Diabetes Care 2011
“Diabetes duration, socioeconomic status, and daily media consumption time are significant risk factors for poor glycemic control”
Hours of Exercise/Week
Aerobic Exercise
Aerobic exercise causes two phases of hypoglycemia and may cause post-exercise highs
45 mincycling
1
2
post-exercise rise
Pumpers can have less post-exercise rise than those on needles
Yardley et al., 2012, Diabetes Technology & Therapeutics
Intense exercise causes a rise:The 10-Second Sprint
Fahey et al., JCEM 2012
Subjects with Type 1 Diabetes Non-diabetic subjects
Hypoglycemia
Hyperglycemia
ANAEROBICShort durationHigh-intensity
AEROBICLonger durationLower Intensity
Types of Exercise Weightlifting, Power lifting
Track (sprinting & field events), Diving (Platform & springboard)
American football, Swimming (sprints), Gymnastics, Fencing
Wrestling, Volleyball, Ice hockey, Track cycling
Basketball, Soccer, Tennis, Lacrosse
Speed skating (500-1000m)
Skiing (slalom & downhill), Field hockey
Rowing (middle distance)
Running (middle distance), Speed skating (>1500m)
Road cycling
In-line skating
Cross country skiing
Race walking
Marathon running
Iron Man triathlon
Ultra-marathon running
Resistance Exercise
Resistance exercise may be better than Aerobic exercise for glucose control
Yardley et al., Diabetes Care, 2012
Resistance exercise first protects against hypoglycemia during Aerobic exercise
Yardley et al., Diabetes Care, 2012
Bracken, West and Bain, Pre-exercise Insulin and Carbohydrate Strategies in the Exercising T1DM Individual. In Clinical Management of the Athlete Editor: Ian Gallen.Springer-Verlag, London 2012
Components of good blood glucose management prior to physical activity
MDI adjustments for Aerobic exercise
1. Ex carbs (tables available or approximate 1 g/kg body mass per hour of activity)
2. Lower pre-meal bolus insulin by 25-75% and consider adding 10-15 g CHO at the start of the activity
3. With day-long or unusual activities such as camps, tournaments etc. consider a 30-50% reduction of long-acting insulin the night before and on the day of the activity
Robertson K et al. Pediatr Diabetes 2009 ;10 (Suppl 12):154–68
ExCarbswww.yorku.ca/mriddell/
MDI adjustments for Aerobic exercise
1. Ex carbs (tables available or approximate 1 g/kg body mass per hour of activity)
2. Lower pre-meal bolus insulin by 25-75% and consider adding 10-15 g CHO at the start of the activity
3. With day-long or unusual activities such as camps, tournaments etc. consider a 30-50% reduction of long-acting insulin the night before and on the day of the activity
Robertson K et al. Pediatr Diabetes 2009 ;10 (Suppl 12):154–68
Duration of exercise Intensity of exercise
30 minutes
60 minutes
Mild 25% 50%
Mod 50%
75%
Heavy 75%
Pump Adjustments for Aerobic Exercise- Temp Basal Adjustments
• Consider reducing basal insulin infusion rates by about 50%, 60-90 minutes before the start of aerobic type exercise that lasts >30 minutes.
• Also consider a temp basal during sleep– 20% reduction in basal insulin rate
overnight
Hypoglycemia management strategies - CSII
1. Suspend/reduce basal insulin by 30-100%, 60-90 minutes BEFORE the start of exercise until the end of the activity• Disconnection/suspension should be
no more than 2 hours
2. Ex carbs- can be much lower if insulin adjustments are made (8-20g/hour)
3. Reduce the mealtime bolus by 25-75%
Robertson K et al. Pediatr Diabetes 2009 ;10 (Suppl 12):154–68
Insulin units
Time: 0.00 6.00 12.00 18.00 24.00
Absent basal rate
Basal rate
Hypoglycemia Management Strategies- Summary
1. Ex carbs (~1 gram per kg body mass per hour of exercise) when relative hyperinsulinemia exists
2. Lowering pre-meal bolus insulin (25-75%)3. Suspend/reduce basal insulin (60-90 minutes
BEFORE exercise)4. Prevention using frequent BG testing and
CGM
Exercise with Real-Time CGM
Real-Time Continuous Glucose Monitoring and Small Amounts of Carbohydrate Prevent Hypoglycemia in Active Youth with T1DM
Riddell and Millikin, Diabetes Technology & Therapeutics, 2011
hockey
We find that sports like hockey can increase glucose in early recovery and cause hypoglycemia later at night during sleep... CGM can help identify these issues
Pizza, Choc Milk (53g)50% bolus (MDI)
hockey
Suggestions for post-exercise hyperglycemia
• Resume normal insulin basal rate if on a pump (cancel any temp basal)
• Replace ½ of the missed basal insulin as a correction bolus• Calculate insulin correction bolus and divide by ½ (MDI or
pump)• Correct any hyperglycemia conservatively at the next meal
(MDI or pump)
Real-Time CGM Allows for Proactive Measures
race
1. 8:00AM breakfast (oatmeal, yogurt and fruit)
1 2
2. 10:30 AM basal reduction to 50% for 3 hours
3
3. 11:45 race start-Ex carbs: (~60 grams in total)
4
4. 2:00PM race ends- bolus 2 units immediately- glucose still rose
5
5. 3:00PM ate sandwich, fruit, cookies with full bolus
6
6. 5:30PM correction bolus
7
7. 7:00 PM dinner, full bolus
CGM Pros and Cons• Pros: Sensor-augmented pump capacity (auto shut
off), sense of “security”, do not need to stop and poke, can be informative for future titrations in insulin and or carb (Carelink data), helps to identify the areas for improvement, can allow for being proactive/preventative (enhancing stability)
• Cons: Slight delay in equilibration between plasma and interstitial fluid, must be calibrated properly (inherent to all errors of meters plus own error), expense, comfort, acceptance
Factors affecting glucose response
• Duration of activity• Intensity of activity• Type of activity• Metabolic control• Insulin regimen• Absorption of insulin• Timing and type of food• Stress and competition involved
Managing exercise- key points
• Very variable effects in different children• Monitoring glucose is the key• Know glucose value before activity• Snack before the activity• Interrupt activity every 30 minutes for an
additional snack• Monitor glucose 30-60 minutes after the end
of the activity
Managing exercise- key points (2)
• Treat low glucose with additional rapidly-digested food
• After prolonged activity, additional snack before sleeping, and should have glucose monitored during the night
• Accurate records of activity, food intake and glucose values
Carrie Henderson, RD, CDEMcMasterwww.volumesdirect.com