II. Efficacy: Benefits of Exercise in Diabetes Mellitus

  1. Benefits are specific to regular Exercise type
    1. Combined aerobic Exercise (or high intensity intervals) and Resistance Training decreases A1C more than other modality alone
    2. Aerobic Exercise
      1. Decreases Hyperglycemia, reduces Hemoglobin A1C by at least 0.5% and reduces daily fluctuations
    3. High Intensity interval training (also aerobic Exercise)
      1. Decreases Hemoglobin A1C more than other forms of Exercise (and also decreases fluctuations)
      2. Improves Insulin sensitivity
      3. Increases pancreatic beta cell function
    4. Resistance Training
      1. Increases Muscle mass and Insulin sensitivity
  2. Exercise lowers Serum Glucose
    1. Benefits Type I Diabetes Mellitus
    2. Benefits Type II Diabetes most significantly
  3. Exercise augments Insulin effect
    1. Facilitates Glucose transport across cell
  4. Exercise reduces heart disease and stroke risk
    1. Increases HDL
    2. Lowers LDL
    3. Lowers Total Cholesterol
    4. Decreases SBP and DBP
  5. Exercise improves general wellness
    1. Increases self esteem
    2. Improves socialization

III. Adverse Effects: Risks of Exercise in Diabetes Mellitus

  1. Hypoglycemia
    1. Use caution in Scuba Diving
    2. Use caution in rock-climbing
    3. Use caution in long-distance swimming
  2. Retinopathy
    1. Avoid weight lifting
    2. Avoid mountain climbing
  3. Neuropathy
    1. Avoid weight bearing Exercises
    2. Choose stationary bike or water sports
  4. Autonomic Dysfunction
    1. Abnormal hemodynamic response to Exercise
      1. Inappropriate Heart Rate response
      2. Inappropriate Blood Pressure response
    2. May not experience Anginal symptoms with Exercise
    3. May not experience hypoglycemic symptoms
  5. Diabetic Nephropathy
    1. Avoid Resistance Training
  6. Cardiovascular disease
    1. Consider Stress Testing prior to moderate to high intensity Exercise program (esp. sedentary over age 30 years)
  7. Musculoskeletal Injury
    1. Higher risk with High Intensity interval training

IV. Approach: Starting Exercise

  1. Evaluate coronary, nephropathy, Neuropathy, Retinopathy
    1. Confirm no contraindications to starting Exercise
  2. Goals
    1. Time
      1. Moderate intensity aerobic Exercise >150 min/week (or vigorous >75 min/week) AND
      2. Resistance Training of all major Muscle groups on at least 2 days per week AND
      3. Consider flexibility and balance activities (Yoga, Tai Chi, Pilates)
    2. Goal Energy Expenditure (See METS)
      1. No weight loss intended: 1000 KCal/week
      2. Weight loss intended: 2000 KCal/week
  3. Aerobic Exercise
    1. See Exercise for examples
    2. Consider 3 minutes of Physical Activity for every 30 minutes of sedentary activity
    3. High Intensity interval training (repeated in intervals)
      1. Perform 10 seconds to 4 minutes of vigorous Exercise to 75 to 95% of maximum Heart Rate AND THEN
      2. Recover with 5 minutes of relative rest or light activity (e.g. walking)
  4. Progressive Resistance Training
    1. Low resistance (40-60% of 1 repetition maximum)
    2. Low intensity
    3. Gradually increase to 15-20 repetitions

V. Approach: General Exercise Tips in Diabetes Mellitus

  1. Preparation for regular Exercise
    1. Check feet for lesions related to Exercise
    2. Pre-Exercise evaluation (consider Stress Test)
    3. Medic-Alert tag
    4. Exercising diabetics must use Glucometer
    5. Pre-planned strategy for Hypoglycemia
    6. Evaluate Exercise Energy Expenditure (METS)
  2. Be aware of medication and Diabetes impact on Exercise-related adverse effects
    1. Exercise-Induced Hypoglycemia (esp. Insulin and Insulin Secretagogues)
      1. Higher risk with longer duration or high intensity Exercise
      2. Consider medication dose adjustments and snacks around the time of Exercise
      3. Check finger stick Blood Sugar before Exercise (and during Exercise for Hypoglycemia symptoms)
    2. Volume Depletion (esp. with SGLT2 Inhibitor, Hyperglycemia)
      1. Maximize hydration before and during Exercise
      2. Electrolyte solutions may be indicated if sweating during >60 minutes of continuous Exercise
        1. Caution regarding Glucose containing Electrolyte solutions
    3. Heat Illness Risk (altered Thermoregulation and decreased vasodilation in diabetes)
      1. See Heat Illness Prevention
  3. Time Exercise appropriately
    1. Best effect on glycemic control is with afternoon Exercise (compared with morning)
    2. Avoid late-evening Exercise in Type I Diabetes
    3. Aerobic Exercise recommended 6 to 7 days per week
      1. Duration: 20 to 60 minutes
      2. Level: 60-80% of maximum Heart Rate
    4. Allow time for warm up and cool down
      1. Reduces injury risk
      2. Reduces post-exercise Arrhythmia risk
    5. Perform light activity throughout the day
      1. Rise from sitting every 30 minutes

VI. Management: Blood Sugar in the peri-Exercise period

  1. Check pre-exercise Blood Sugar
    1. Blood Sugar <100 mg/dl
      1. Snack 15-20 grams Carbohydrate before Exercise
    2. Blood Sugar 100 to 250 mg/dl
      1. No snack needed
    3. Blood Sugar >250 with Ketones (or >300 without)
      1. Delay Exercise
      2. Check Serum Ketones
      3. Treat Hyperglycemia and Dehydration
  2. Pre-ExerciseInsulin
    1. Take Insulin more than 1 hour before Exercise
    2. Inject Insulin into a non-exercising site
      1. Absorption at Abdomen is fastest and most reliable
    3. Decrease Short-Acting Insulin before Exercise
      1. Decrease 30% for Exercise less than 1 hour
      2. Decrease 40% for Exercise 1-2 hours
      3. Decrease 50% for Exercise over 3 hours
  3. Decrease risk of Hypoglycemia
    1. Avoid Exercise during times of peak Insulin activity
    2. Consider Humalog Insulin
    3. Insulin injection site may affect absorption rate
    4. Avoid Sulfonylurea
  4. Be aware of your own Blood Sugar response to Exercise
    1. Pre-Exercise Food
      1. Meals should be ingested 1-2 hours before Exercise
      2. Strenuous or prolonged Exercise
        1. Start increasing calorie intake 24 hours before
        2. Supplement Carbohydrates every 30 minutes during
    2. Supplement during Exercise with Glucose solutions
      1. One bottle for each 30 minutes strenuous Exercise
    3. Replenish glycogen stores after Exercise
      1. Based on Exercise duration and intensity
      2. Be aware of delayed Hypoglycemia
  5. Carry an activity pack while exercising
    1. Personal identification
    2. Mobile phone
    3. Adequate water and Carbohydrate source
    4. Blood Glucose monitor

VII. Complications: Post-exercise Hypoglycemia

  1. Delayed Hypoglycemia
    1. Occurs 6 to 28 hours after strenuous Exercise
    2. Occurs despite normal Blood Sugars during Exercise
    3. Occurs regardless of age or illness severity
    4. Often occurs at night
  2. Mechanism
    1. Glycogen stores depleted and not replenished
    2. Increased Insulin sensitivity post-Exercise

VIII. Resources

  1. Diabetes, Exercise and Sports Association
  2. Mountains for Active Diabetics (extreme sports)
    1. http://www.mountain-mad.org

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