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

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Objectives

Explain briefly why exercise is so important for our diabetes Provide an overview of the physiology of exercise and diabetes Outline some pump and insulin injection strategies to improve blood sugar control during (and after) exercise Discuss the advantages and limitations of continuous glucose monitoring (CGM) for exercise

Exercise, why bother?

• 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)

Diabetes and exercise BENEFITS RISKS • 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

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 BG levels Person with diabetes BG levels Insulin “levels” Insulin release

Hyperglycemia and Exercise

Competitive

events and/or can cause

high intensity hyperglycemia

exercise 50% correction bolus

Competition

Exercise and Diabetes: Advanced

Increased by

food

Decreased by

Exercise Insulin 5-7mM Balanced Blood Sugar

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)

Hours of Exercise/Week N= 296 children, adolescents, and young adults with type 1 diabetes “Diabetes duration, socioeconomic status, and daily media consumption time are significant risk factors for poor glycemic control” Galler et al., Diabetes Care 2011

Aerobic Exercise

Aerobic exercise causes two phases of hypoglycemia and may cause post-exercise highs post-exercise rise 1 2

45 min cycling

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

Subjects with Type 1 Diabetes Non-diabetic subjects Fahey et al., JCEM 2012

Types of Exercise

Hyperglycemia

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 ANAEROBIC Short duration High-intensity AEROBIC Longer duration Lower Intensity

Hypoglycemia

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

Components of good blood glucose management prior to physical activity Bracken, West and Bain,

Pre-exercise Insulin and Carbohydrate Strategies in the Exercising T1DM Individual

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Clinical Management of the Athlete

Springer-Verlag, London 2012 Editor: Ian Gallen.

MDI adjustments for Aerobic exercise

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Ex carbs (tables available or approximate 1 g/kg body mass per hour of activity) Lower pre-meal bolus insulin by 25-75% and consider adding 10-15 g CHO at the start of the activity 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

ExCarbs www.yorku.ca/mriddell/

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MDI adjustments for Aerobic exercise

Ex carbs (tables available or approximate 1 g/kg body mass per hour of activity) Lower pre-meal bolus insulin by 25-75% and consider adding 10 15 g CHO at the start of the activity 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 Duration of exercise Intensity of exercise

Mild Mod Heavy

30 minutes

25% 50% 75%

60 minutes

50% 75%

Robertson K et al. Pediatr Diabetes 2009 ;10 (Suppl 12):154–68

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% Insulin units Time: 0.00

6.00

12.00

Basal rate Absent basal rate 18.00

24.00

Robertson K et al. Pediatr Diabetes 2009 ;10 (Suppl 12):154–68

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

hockey Pizza, Choc Milk (53g) 50% bolus (MDI)

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 1 2 4 5 6 1. 8:00AM breakfast (oatmeal, yogurt and fruit) 2. 10:30 AM basal reduction to 50% for 3 hours 3. 11:45 race start-Ex carbs: (~60 grams in total) 4. 2:00PM race ends- bolus 2 units immediately- glucose still rose 5. 3:00PM ate sandwich, fruit, cookies with full bolus 6. 5:30PM correction bolus 7. 7:00 PM dinner, full bolus 7

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, CDE McMaster www.volumesdirect.com