If physical activity is done between meals

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Check your blood sugar before starting physical activity, especially if it is not planned (and you did not reduce your insulin dose at the previous meal).



1.blood sugar <70: take sugar, wait 1 hour and measure blood sugar again
2. glycemia between 70-100: take different amounts of sugar according to the type of load (15 g light, 25 g medium)
3. glycemia between 100-180: take different amounts of sugars according to the type of load you will exercise (no extra for light, 15 g for medium, 25 g for intense)
4. blood sugar level above 180: do not take any dietary supplements
5. avoid exercise if blood sugar is greater than 250 mg/dL and ketosis is present
6. Caution if levels are > 300 and ketosis is not present: do not exert any physical effort, administer 2-3 units of rapid insulin and retest blood sugar after 1 hour.


a) Learn the glycemic response to various exercises to determine if changes in insulin or food intake will be necessary in subsequent workouts.
Remember that very intense physical activity can also cause excessive production of glucose in the liver, stimulated by adrenaline, causing hyperglycemia.
b) Foods rich in carbohydrates should be readily available during and after exercise.
c) correction of hypoglycemia should be done by consuming snacks containing simple sugars, preferably in an aqueous solution (eg: fruit juices, water with 3 bags of sugar or cola).
On the other hand, prevention must be done with complex carbohydrates (e.g. crackers, biscuits: 25-30 g per hour of activity), which will ensure a longer-lasting sugar intake.

For cross-country skiers, it may be useful to use supplements containing maltodextrin (powders containing “moderately” absorbable sugars) in a 5-8% solution, which will ensure a slow and steady supply of sugars in proportion to their consumption.


a) Check your blood sugar level one hour after sports activity, especially if you are poorly trained and try in the evening or afternoon to avoid late hypoglycemia. If the effort is intense and long-term, it is advisable to measure blood glucose also at night.
b) it is often necessary to reduce the bolus of the following meal by about 25% to avoid hypoglycemia.



For a person with type 1 diabetes who is treated with a pump, they need to acquire a little different knowledge.
For activity equal to or longer than 30 minutes, it is necessary to change the insulin dosage:
a) Basal

• Before: reduce by 30% one hour before physical activity, especially if it is moderately intense and lasts more than 30 minutes.
• During: decrease from 20 to 50% (it depends a lot on the current baseline: if it is very low, eg 0.4-0.5 IU per hour, a maximum decrease of 25% is recommended).
• After: 20% reduction for up to 12 hours.
• If you are not exercising, the baseline reduction should be slightly greater.
b) Boluses
• The differences depend a lot on the time of day in which the physical activity is performed; especially if it is done in the hours after a meal, it is advisable to practice it 2-4 hours later
• in this case, it is necessary to reduce the food bolus before physical activity by 25-75%, also depending on the length and intensity of the exercise; for intense and prolonged efforts (marathon) also reduce the bolus of the next meal by 25-50%.