exercise and type I diabetes

Last reviewed 02/2022

Exercise has been shown to bring many benefits to those who have type 1 diabetes and rely on insulin to control blood glucose levels.

These include

  • lower cardiovascular risk, and better cardiovascular function
    • better control of blood sugars, blood pressure, and weight
  • improved insulin sensitivity, lower insulin requirements

All of these lead to improvements in the health outcomes for patients with type 1 diabetes ultimately leading to a longer lifespan (1, 2)

  • in type 1 diabetes, there is a reduction in insulin requirements both during exercise and 24 hours afterwards. Reasons include:
    • there is a more rapid absorption of insulin from an exercising rather than non-exercising limb
    • there is an increase in insulin-dependent glucose uptake as a result of exercise

  • type 1 diabetics need to carefully monitor glucose when commencing on an exercise regimen; also they should be advised to reduce insulin doses before and after exercising (especially if using long-acting insulin)

Advice for patients (3,4,5,6,7,8)

  • diabetic patients, especially those using insulin, need to know how their glycaemic control can be affected by different forms of physical activity
    • patients' confidence can be increased by appropriate advice on checking blood glucose concentrations before and after activity, and, with respect to insulin treated diabetics, carrying rapid- and intermediate-acting carbohydrate whenever they plan to exercise

  • for type 2 diabetics taking oral medication for diabetes
    • a reduction in the dose may be required if prolonged exercise is planned

  • for type 1 diabetics
    • guidelines recommend that, because of the risk of precipitating ketoacidosis, exercise should be avoided if the fasting glucose concentration before physical activity is more than 13 mmol/L and ketosis is present (6)
    • the guidelines also advise caution if glucose concentration is more than 17 mmol/L and no ketosis is present
    • if blood sugar level is above 13 mmols/l but less than 17 mmols/l, limit exercise activity to moderate intensity (walking, light biking), rather than a high intensity exercise (running, weight lifting, tennis) (6)
    • amount of exercise
      • 150 minutes of moderate aerobic activity, or 75 mins strenuous activity
      • 1 hour of resistance exercise
    • it is important for those exercising who have diabetes that they monitor their blood sugar levels frequently especially before and after exercise (5,6)
    • if required they may need to monitor their levels during exercise as well, especially if doing prolonged exercise (5,6)
    • it should be noted that a reduction in Insulin requirement will last for 12-15 hours following any exercise and Insulin should be adjusted accordingly (3,4,5,8)
    • if blood sugar is <5.5mmol/l take a carbohydrate snack prior to exercise
    • additional carbohydrates (30-60g/hour) should be consumed every 30-60 minutes of exercise to avoid hypoglycaemia
    • when exercising participants should make others aware of their condition and also be aware themselves of how they feel when they may be getting a low blood sugar
    • consider wearing an alert bracelet
    • consult early if non healing foot ulcers or particular concern
    • consult doctor before doing extreme sports including scuba diving, climbing, surfing, parachuting

Resources for GP's/ Patients

Contributors:

  • Dr Alethea Beck. General Practitioner, Scottish Borders
  • Dr Andrew Murray. General Practitioner, Sports and Exercise Medicine registrar, Scotland

Reference:

Related pages:

insulin

exercise and type II diabetes