Impact of pre-exercise rapid-acting insulin reductions on ketogenesis following running in Type 1 diabetes

Diabet Med. 2011 Feb;28(2):218-22. doi: 10.1111/j.1464-5491.2010.03162.x.


Aim: This study examined the effects of reductions to pre-exercise rapid-acting insulin dose on changes in blood beta-hydroxybutyrate, glucose, acid-base balance and counter-regulatory hormone responses to prolonged running in individuals with Type 1 diabetes.

Methods: Following ethical approval, seven participants with Type 1 diabetes (34±2 years, BMI 27±1 kg/m(2) ) completed this study. After preliminary testing, participants attended the laboratory four times, each time consuming a 1.12 MJ meal (60 g carbohydrate, 2 g fat, 2 g protein), with randomized amounts of their rapid-acting insulin: Full dose (mean 7.3±0.2 units), 75% dose (mean 5.4±0.1 units), 50% dose (mean 3.7±0.1 units) or 25% dose (mean 1.8±0.1 units). After 2-h rest, participants completed 45 min running at 70±1% peak rate of oxygen consumption (VO(2peak) ). Blood metabolites and hormones were recorded over the 2-h rest and 3-h recovery. Data were analysed using repeated-measures ANOVA.

Results: Serum insulin peaked at 60 min in all conditions and was lowest after 25% insulin dose compared with full dose (P=0.03). After the 25% insulin dose immediately pre-exercise glucose concentration was higher than after the full or 50% dose (P<0.05). Resting beta-hydroxybutyrate gradually decreased during 2-h rest (P<0.05) with a similar post-exercise peak of beta-hydroxybutyrate at 3 h (P>0.05). Post-exercise blood pH increased for 5 min to a similar extent with all insulin doses , but the rise with the 25% dose was less compared with the full dose (P=0.01). Blood lactate and plasma catecholamines increased after running similarly with all insulin reduction conditions (P<0.05). Blood glucose area under the curve (BG(auc) ) after the 25% insulin dose was greater than after the 75% dose (P=0.02).

Conclusion: Ketogenesis following running was not influenced by reductions in pre-exercise rapid-acting insulin dose. This important preparatory strategy aids preservation of blood glucose but poses no greater risk to exercise-induced ketone body formation.

Publication types

  • Randomized Controlled Trial
  • Research Support, Non-U.S. Gov't

MeSH terms

  • 3-Hydroxybutyric Acid / blood
  • Adult
  • Blood Glucose / drug effects*
  • Blood Glucose / physiology
  • Body Mass Index
  • Diabetes Mellitus, Type 1 / drug therapy*
  • Diabetes Mellitus, Type 1 / metabolism
  • Diabetes Mellitus, Type 1 / physiopathology
  • Energy Metabolism / drug effects*
  • Energy Metabolism / physiology
  • Female
  • Humans
  • Insulin / administration & dosage
  • Insulin / pharmacokinetics*
  • Ketone Bodies / biosynthesis*
  • Oxygen Consumption / drug effects*
  • Oxygen Consumption / physiology
  • Running / physiology*
  • Treatment Outcome


  • Blood Glucose
  • Insulin
  • Ketone Bodies
  • 3-Hydroxybutyric Acid