Table 1

Suggested carbohydrate intake or other actions based on blood glucose levels at the start of exercise

Pre-exercise blood glucoseCarbohydrate intake or other action
<90 mg/dL (<5.0 mmol/L)
  • Ingest 15–30 g of fast-acting carbohydrate prior to the start of exercise, depending on the size of the individual and intended activity; some activities that are brief in duration (<30 min) or at a very high intensity (weight training, interval training, etc.) may not require any additional carbohydrate intake.

  • For prolonged activities at a moderate intensity, consume additional carbohydrate, as needed (0.5–1.0 g/kg body mass per h of exercise), based on blood glucose testing results.

90–150 mg/dL (5.0–8.3 mmol/L)
  • Start consuming carbohydrate at the onset of most exercise (∼0.5–1.0 g/kg body mass per h of exercise), depending on the type of exercise and the amount of active insulin.

150–250 mg/dL (8.3–13.9 mmol/L)
  • Initiate exercise and delay consumption of carbohydrate until blood glucose levels are <150 mg/dL (<8.3 mmol/L).

250–350 mg/dL (13.9–19.4 mmol/L)
  • Test for ketones. Do not perform any exercise if moderate-to-large amounts of ketones are present.

  • Initiate mild-to-moderate intensity exercise. Intense exercise should be delayed until glucose levels are <250 mg/dL because intense exercise may exaggerate the hyperglycemia.

≥350 mg/dL (≥19.4 mmol/L)
  • Test for ketones. Do not perform any exercise if moderate-to-large amounts of ketones are present.

  • If ketones are negative (or trace), consider conservative insulin correction (e.g., 50% correction) before exercise, depending on active insulin status.

  • Initiate mild-to-moderate exercise and avoid intense exercise until glucose levels decrease.

  • Adapted from Zaharieva and Riddell (88).