Optimizing Insulin Levels for Training and Sport

Dr. Matthew Corcoran, MD

Fundamental aspects of insulin therapy and management and the application to exercise and sport. The goal will be to deliver 3-4 management suggestions to decrease risk of hypo and hyperglycemia.

Transcript

1. Optimizing Insulin Levels for Activity, Exercise & Sport Matthew H Corcoran, MD Diabetes Training Camp Foundation mcorcoran@diabetestrainingcamp.com
2. Objectives • Describe most common glucose response to exercise & physical activity. • Review insulin action & its role in fuel mobilization for the working muscle. • Review impact of over-insulinization & risk of hypoglycemia. • Identify basic insulin management strategies to decrease risk of hypoglycemia and/or hyperglycemia in activity, exercise & sport.
3. Starting BG Level The Diabetes Research in Children Network (DirecNet) Study Group Baseline Hypoglycemi a < 60mg/dL (70) < 120 86% (100) 120 - 180 13% (44) >180 6% (28)
4. Immediate Effects of Exercise • 83% with drop in glucose of at least 25%; Only 1 subject with meaningful increase in BG. • Average fall is 40% from baseline. • 52% drop to < 70 mg/dL and 30% drop to < 60 mg/dL. • I ncidence of hypoglycemia varies with baseline BG. • 15 grams CHO insufficient to reliably treat hypoglycemia in exercise
5. Glucose Infusion Rates (GIR) to Maintain Euglycemia: Biphasic Glucose Requirements Mcmahon et al., JCEM 2007 *p<0. 05 4 3 2 1 0 -1 ∆GIR (mg/kg/min) 1600 1800 2000 2200 2400 0200 0400 Time *** **** * * * ** Late hypoglycemia risk Early hypoglycemia risk * * * * Exercise in afternoon
6. Insulin is an anabolic hormone and acts to store all of our substrates for us to draw upon during times of need: fasting, sleep, physical activity, etc. • Insulin levels are steady and/or low during these times to allow for mobilization of stored fuels for brain function, muscular work, etc.
7. In normal physiology, insulin levels generally decrease to allow for fuel mobilization to release energy stores for utilization and to meet the demand of the working muscles.
8. Glucose Control: Moderate Exercise output intake ↓ Insulin ↑ Glucagon Blood Glucose Constant Without diabetes
9. Glucose Control Modified from Riddell MC & Perkins BA. Can J Diab, 30: 63-71, 2006
14. Possible rate of glucose change: 2-4+ mg/dL/min or Lower rate of change: 1-3 mg/dL/min or Greatest stability Rapid Acting Insulin Curve & Impact on Rate of Change
15. Projected Carb Consumption: HIGH 30-90 grams/hour Projected Carb Consumption: Moderate 15-45 grams per hour Projected Carb Consumption: Lowest Rapid Acting Insulin Curve & Impact on Rate of Change
16. 132 lbs 176 lbs 198 lbs 220 lbs 1 hour after bolus 37 +/- 50 +/- 56 +/- 63 +/- 2.5 hours after bolus 26 +/- 35 +/- 39 +/- 44 +/- 4 hours after bolus 16 +/- 22 +/- 25 +/- 28 +/- 5 hours after bolus 8 +/- 11 +/- 12 +/- 14 +/- Estimated CHOs to Prevent Hypoglycemia Based upon Weight and Time Interval Between Bolus (With Some Variability) Francescato, et al. Metabolism, Vol 53, No 9, 2004: 1126-1130.
17. With type 1 diabetes the athlete is generally overinusilinized for the level of physical activity that you are doing: • This limits: –ability to mobilize fuel stores –generate glucose as a substrate for the working muscle. –the body’s ability to keep up with the muscular glucose uptake during exercise.
18. There is some control over the athlete’s fuel metabolism, generally through: • adjusting/modifying insulin levels • consuming carbohydrates • a combination of both approaches.
19. Optimize Insulin Levels • Limit peaking insulin levels • Optimize background insulin levels
20. A background of basal insulin (generally at a reduced level) will provide a smoother ride in terms of glucose responses to exercise. Rapid acting boluses/peaking insulin creates much more instability & flux.
21. Basal Insulin Considerations Injections Traditional Pump Automation • Limited ability to manipulate. • May be able to adjust about 20-30% with shorter acting long acting insulins. • Understand how you respond to different long acting insulin throughout the 24 hour day. • Understand natural history. • Basal rate reductions mimic normal physiology. • Consider starting with 30% reductions. • Recommended: 90-120 minutes prior to exercise session. • Temp Target, Exercise Mode • May require more aggressive fueling plans. • Impact of auto corrections • Other strategies to avoid overinsulinization?
22. Basal Insulin Considerations Injections Traditional Pump Automation • Long acting insulin contributes to the 12-24 hour basal insulin supply. • Typically supplies 50- 100% of basal need. • Allows maintenance of basal insulin supply during pump disconnect and/or basal reduction. • Understand how you respond to different long acting insulin throughout a 12- 24 hour period. • Basal rate reductions mimic normal physiology. • Consider starting with 30% reductions. • Can reduce basal and/or essentially stop basal supply and maintain background insulin. • Recommended: 90-120 minutes prior to exercise session. • Can utilize pump for boluses/corrections. • Temp Target, Exercise Mode • May require more aggressive fueling plans. • Impact of auto corrections • Other strategies to avoid overinsulinization?
23. Basal Insulin Considerations Based Upon Goal Weight Management Fitness Sports/Endurance • Minimize basal insulin & avoid rapid acting insulin before exercise. • MDI- may be able to adjust shorter acting basal insulin. Exercise at less potent times. • Understand how you respond to different long acting insulin throughout the 24 hour period. • Choose appropriate basal for your goals. • Understand natural history – may or may not need change. • Basal rate reductions may mimic normal physiology. • Consider starting with 30% reductions. • Recommended: 90-120 minutes prior to exercise session. • MDI- may consider exercise at less potent times. • Basal rate reductions may mimic normal physiology. • Higher intensity work/stress may require higher basal insulin levels at times. • Consider starting with 30% reductions. • Recommended: 90-120 minutes prior to training session through session. • Endurance: May need to reduce to 30-50% of normal with longer duration.
24. Pump Strategy & Potential Impact on Insulin Levels 1 HOUR 2 HOURS 3 HOURS Pump Disconnect 50% 60% 70% 50% basal reduction 5% 15% 20% Insulin Levels May Decrease Pump Intervention
25. DIABETES CARE, VOLUME 21, NUMBER 5, MAY 1998 Insulin interruption & resulting insulin levels and metabolic control (pump disconnect in well controlled type 1 DM). The Pump Disconnect and Timing of Insulin Changes. Plasma insulin levels fell by: ∼50% at one hour ∼60% at two hours ∼70% at three hours
26. 0 50 100 150 200 250 300 0 min 30 min 60 min 90 min 120 min 150 min 180 min 50-75% reduction Full Meal Dose Meal/Snack Start workout at 70% maximal intensity Glucose mg/dL Dosing the pre-workout meal or snack
27. My Awesome New CGM Exercise Session
28. Pharmacodynamics of TI: mean baseline-corrected glucose infusion rate of TI versus RAA in type 1 diabetes J Diabetes Sci Technol. 2017 Jan; 11(1): 148–156. More rapid onset of action and shorter duration of metabolic effect than subcutaneously injected rapid acting insulin. 30 min 150 min At 120 minutes, inhaled insulin had delivered 60% of the total glucose lowering effect vs.33% for insulin lispro.
29. Practical Application • Optimize your starting glucose AND insulin level, and consider starting conservatively. • Separate exercise and/or training and meal boluses by 3-4 hours, or more - Exercise in AM before breakfast and/or before meals. • If exercising within 1-2 hours of meal bolus, strongly consider 25-75% reduction depending upon duration and intensity. • Need for carbohydrate consumption will, in part, be based upon peaking insulin levels (IOB).
30. Four basic strategies that we are advocating for in order to simplify, minimize the variables & impact your performance and results: • Work out and train on basal insulin only as much as possible & 3 to 4 hours removed from rapid acting boluses. – Consider starting with 70% of normal basal insulin levels. • Minimize the action of rapid acting boluses/peaking insulin. • Utilize adequate carbohydrates to prevent hypoglycemia(as necessary) and/or fuel longer duration activities. • Avoid hypoglycemia as much as possible. Strive to stay above 70 mg/dl. Hypoglycemia is a vicious cycle and it will create havoc over the next 24 hours or more.
31. 2022 – Current State of Affairs • Imperfect pancreas and beta cells. • Imperfect insulins. • Imperfect meters. • Imperfect pumps. • Imperfect CGMs. • Imperfect strategies. • Imperfect camps and programs.
32. Thank You For Being Here Tonight!