title: Insulin therapy and dietary adjustments to normalize glycemia and prevent nocturnal hypoglycemia after evening exercise in type 1 diabetes: a randomized controlled trial.
abstract: BACKGROUND
  Evening-time exercise is a frequent cause of severe hypoglycemia in type 1 diabetes, fear of which deters participation in regular exercise. Recommendations for normalizing glycemia around exercise consist of prandial adjustments to bolus insulin therapy and food composition, but this carries only short-lasting protection from hypoglycemia. Therefore, this study aimed to examine the impact of a combined basal-bolus insulin dose reduction and carbohydrate feeding strategy on glycemia and metabolic parameters following evening exercise in type 1 diabetes.
  
  
  METHODS
  Ten male participants (glycated hemoglobin: 52.4±2.2 mmol/mol), treated with multiple daily injections, completed two randomized study-days, whereby administration of total daily basal insulin dose was unchanged (100%), or reduced by 20% (80%). Participants attended the laboratory at ∼08:00 h for a fasted blood sample, before returning in the evening. On arrival (∼17:00 h), participants consumed a carbohydrate meal and administered a 75% reduced rapid-acting insulin dose and 60 min later performed 45 min of treadmill running. At 60 min postexercise, participants consumed a low glycemic index (LGI) meal and administered a 50% reduced rapid-acting insulin dose, before returning home. At ∼23:00 h, participants consumed a LGI bedtime snack and returned to the laboratory the following morning (∼08:00 h) for a fasted blood sample. Venous blood samples were analyzed for glucose, glucoregulatory hormones, non-esterified fatty acids, β-hydroxybutyrate, interleukin 6, and tumor necrosis factor α. Interstitial glucose was monitored for 24 h pre-exercise and postexercise.
  
  
  RESULTS
  Glycemia was similar until 6 h postexercise, with no hypoglycemic episodes. Beyond 6 h glucose levels fell during 100%, and nine participants experienced nocturnal hypoglycemia. Conversely, all participants during 80% were protected from nocturnal hypoglycemia, and remained protected for 24 h postexercise. All metabolic parameters were similar.
  
  
  CONCLUSIONS
  Reducing basal insulin dose with reduced prandial bolus insulin and LGI carbohydrate feeding provides protection from hypoglycemia during and for 24 h following evening exercise. This strategy is not associated with hyperglycemia, or adverse metabolic disturbances.
  
  
  BACKGROUND
  NCT02204839, ClinicalTrials.gov.
authors.affiliation: Faculty of Health and Life Sciences , Northumbria University , Newcastle-upon-Tyne , UK.
authors.forename: Matthew D
authors.initials: MD
authors.lastname: Campbell
authors.affiliation: Institute of Cellular Medicine, Newcastle University , Newcastle-upon-Tyne , UK.
authors.forename: Mark
authors.initials: M
authors.lastname: Walker
authors.affiliation: Diabetes Research Group , College of Medicine, Swansea University , Swansea , UK.
authors.forename: Richard M
authors.initials: RM
authors.lastname: Bracken
authors.affiliation: Diabetes Research Group , College of Medicine, Swansea University , Swansea , UK.
authors.forename: Daniel
authors.initials: D
authors.lastname: Turner
authors.affiliation: Faculty of Health and Life Sciences , Northumbria University , Newcastle-upon-Tyne , UK.
authors.forename: Emma J
authors.initials: EJ
authors.lastname: Stevenson
authors.affiliation: Faculty of Health and Life Sciences , Northumbria University , Newcastle-upon-Tyne , UK.
authors.forename: Javier T
authors.initials: JT
authors.lastname: Gonzalez
authors.affiliation: Institute of Cellular Medicine, Newcastle University , Newcastle-upon-Tyne , UK.
authors.forename: James A
authors.initials: JA
authors.lastname: Shaw
authors.affiliation: Faculty of Health and Life Sciences , Northumbria University , Newcastle-upon-Tyne , UK.
authors.forename: Daniel J
authors.initials: DJ
authors.lastname: West
keywords: Exercise; Hypoglycemia; Insulin; Type 1