title: Glycemic control during consecutive days with prolonged walking exercise in individuals with type 1 diabetes mellitus.
abstract: OBJECTIVE
  Despite its general benefits for health, exercise complicates the maintenance of stable blood glucose concentrations in individuals with type 1 diabetes. The aim of the current study was to examine changes in food intake, insulin administration, and 24-h glycemic control in response to consecutive days with prolonged walking exercise (∼8h daily) in individuals with type 1 diabetes.
  
  
  METHODS
  Ten individuals with type 1 diabetes participating in the worlds' largest walking event were recruited for this observational study. Simultaneous measurements of 24-h glycemic control (continuous glucose monitoring), insulin administration and food intake were performed during a non-walking day (control) and during three subsequent days with prolonged walking exercise (daily distance 40 or 50km).
  
  
  RESULTS
  Despite an increase in daily energy (31±18%; p<0.01) and carbohydrate (82±71g; p<0.01) intake during walking days, subjects lowered their insulin administration by 26±16% relative to the control day (p<0.01). Average 24-h blood glucose concentrations, the prevalence of hyperglycemia (blood glucose >10 mmol/L) and hypoglycemia (blood glucose <3.9mmol/L) did not differ between the control day and walking days (p>0.05 for all variables). The prolonged walking exercise was associated with a modest increase in glycemic variability compared with the control day (p<0.05).
  
  
  CONCLUSIONS
  Prolonged walking exercise allows for profound reductions in daily insulin administration in persons with type 1 diabetes, despite large increments in energy and carbohydrate intake. When taking such adjustments into account, prolonged moderate-intensity exercise does not necessarily impair 24-h glycemic control.
authors.affiliation: Institute of Sport and Exercise Studies, HAN University of Applied Sciences, Nijmegen, The Netherlands; Department of Human Movement Sciences, NUTRIM School for Nutrition, Toxicology and Metabolism, Maastricht University Medical Centre+, Maastricht, The Netherlands.
authors.forename: Jan-Willem
authors.initials: JW
authors.lastname: van Dijk
authors.affiliation: Department of Physiology, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands; Research Institute for Sports and Exercise Sciences, Liverpool John Moores University, Liverpool, United Kingdom.
authors.forename: Thijs M
authors.initials: TM
authors.lastname: Eijsvogels
authors.affiliation: Department of Human Movement Sciences, NUTRIM School for Nutrition, Toxicology and Metabolism, Maastricht University Medical Centre+, Maastricht, The Netherlands; Department of Physiology, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands.
authors.forename: Jean
authors.initials: J
authors.lastname: Nyakayiru
authors.affiliation: Department of Physiology, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands.
authors.forename: Tim H A
authors.initials: TH
authors.lastname: Schreuder
authors.affiliation: Department of Physiology, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands.
authors.forename: Maria T
authors.initials: MT
authors.lastname: Hopman
authors.affiliation: Department of Physiology, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands; Research Institute for Sports and Exercise Sciences, Liverpool John Moores University, Liverpool, United Kingdom.
authors.forename: Dick H
authors.initials: DH
authors.lastname: Thijssen
authors.affiliation: Institute of Sport and Exercise Studies, HAN University of Applied Sciences, Nijmegen, The Netherlands; Department of Human Movement Sciences, NUTRIM School for Nutrition, Toxicology and Metabolism, Maastricht University Medical Centre+, Maastricht, The Netherlands. Electronic address: L.vanloon@maastrichtuniversity.nl.
authors.forename: Luc J C
authors.initials: LJ
authors.lastname: van Loon
mesh_terms: D001786:Blood Glucose / Q000032:analysis; D003922:Diabetes Mellitus, Type 1 / Q000503:physiopathology*; D004435:Eating; D015444:Exercise / Q000502:physiology*; D005260:Female; D006801:Humans; D006943:Hyperglycemia / Q000453:epidemiology*; D007003:Hypoglycemia / Q000453:epidemiology*; D007328:Insulin / Q000097:blood; D008297:Male; D008875:Middle Aged; D009426:Netherlands / Q000453:epidemiology; D015995:Prevalence; D016138:Walking / Q000502:physiology*
chemical_list: D001786:Blood Glucose; D007328:Insulin
keywords: Exercise; Glycemic control; Insulin; Physical activity; Type 1 diabetes mellitus; Walking