Safety and magnitude of changes in blood glucose levels following exercise performed in the fasted and the postprandial state in men with type 2 diabetes

Eur J Cardiovasc Prev Rehabil. 2007 Dec;14(6):831-6. doi: 10.1097/HJR.0b013e3282efaf38.


Background: Information on the extent to which acute exercise reduces blood glucose levels (BGL) in type 2 diabetes is lacking. For this reason, the effects of exercise initiated at different preexercise BGL were assessed in men with type 2 diabetes both in the fasted (FS) and the postprandial states (PS).

Design and methods: Forty-three men with type 2 diabetes, 12 on diet alone and 31 on hypoglycaemic agents, completed a total of 1555 exercise sessions performed in the FS and 0-1, 1-2, 2-3, 3-4, 4-5, and 5-8 h in the PS. Capillary BGL were measured before and immediately after a 1h standardized aerobic exercise session on an ergocycle at 60% of VO2 peak.

Results: In the FS, there was an increase in postexercise BGL of 27+/-21% (mean+/-SD; P<0.001) when preexercise BGL was < or =6 mmol/l, no change when preexercise BGL were between 6 and 8 mmol/l, and a significant decrease of 12+/-13% when preexercise BGL were >8 mmol/l (P<0.001). In the PS, most exercise sessions were associated with significant decreases in BGL ranging between 18+/-17 and 50+/-12% (P<0.001), depending on the time interval between meals and the onset of exercise. Regarding the metabolic PS, the decline in BGL was most pronounced with high preexercise BGL.

Conclusions: Our observations not only demonstrate that it was safe for middle-aged obese men with type 2 diabetes to exercise in the FS, but also show that the decrease in BGL during aerobic exercise was largely dependent on preexercise BGL.

MeSH terms

  • Blood Glucose / metabolism*
  • Diabetes Mellitus, Type 2 / blood*
  • Diabetes Mellitus, Type 2 / physiopathology
  • Diabetes Mellitus, Type 2 / rehabilitation
  • Exercise / physiology*
  • Exercise Therapy / methods*
  • Fasting / physiology*
  • Follow-Up Studies
  • Humans
  • Male
  • Middle Aged
  • Postprandial Period / physiology*
  • Prognosis
  • Severity of Illness Index


  • Blood Glucose