title: Effect of Exercise Intensity on Glucose Requirements to Maintain Euglycemia During Exercise in Type 1 Diabetes.
abstract: BACKGROUND
  No recommendations exist to inform the carbohydrate amount required to prevent hypoglycemia associated with exercise of different intensities in individuals with type 1 diabetes (T1D).
  
  
  OBJECTIVE
  The relationship between exercise intensity and carbohydrate requirements to maintain stable euglycemia in individuals with T1D remains to be determined. It was predicted that an "inverted-U" relationship exists between exercise intensity and the amount of glucose required to prevent hypoglycemia during exercise at basal insulinemia. Our objective was to investigate this relationship and elucidate the underlying glucoregulatory mechanisms.
  
  
  METHODS
  We subjected nine individuals (mean ± SD age, 21.5 ± 4.0 years; duration of disease, 11.4 ± 6.4 years; glycated hemoglobin, 7.9 ± 0.8% [60 mmol/mol]; body mass index, 25.4 ± 5.5 kg/m(2); VO2peak, 34.8 ± 5.1 mL·kg(-1)·min(-1); and lactate threshold, 59.9 ± 5.9% VO2peak) with T1D to a euglycemic clamp, whereby euglycemia was maintained by infusing basal insulin rates with concomitant infusion of [6,6-(2)H2]glucose for determining glucose kinetics. Glucose was infused to maintain euglycemia during and for 2 hours after exercise of different intensities (35, 50, 65, and 80% VO2peak).
  
  
  METHODS
  The glucose infusion rate (GIR), levels of glucoregulatory hormones, and rates of endogenous glucose appearance and disappearance were compared between conditions.
  
  
  RESULTS
  The mean GIR to maintain euglycemia during exercise increased with intensity up to 50% (4.0 ± 1.6 g/h; P < .05) and 65% (4.1 ± 1.7 g/h), but no glucose was required at 80% VO2peak. Glucose rate of appearance and disappearance increased with intensity and, together with plasma catecholamines, reached higher levels at 80% VO2peak.
  
  
  CONCLUSIONS
  Our findings support the predicted inverted-U relationship between exercise intensity and glucose requirement. However, the relationship between iv and oral glucose requirements needs to be investigated to translate these GIR data to clinical practice.
authors.affiliation: Department of Endocrinology and Diabetes (V.B.S., N.P., M.N.C., E.A.D., T.W.J.), Princess Margaret Hospital for Children, Perth, Western Australia 6840, Australia; and School of Paediatrics and Child Health (V.B.S., E.A.D., T.W.J.), School of Sport Science, Exercise, and Health (P.A.F.), and Telethon Kids Institute, The Centre for Child Health Research (R.J.D., A.J.R., N.P., H.C.R., M.N.C., E.A.D., T.W.J.), The University of Western Australia, Perth, Western Australia 6008, Australia.
authors.forename: Vinutha B
authors.initials: VB
authors.lastname: Shetty
authors.affiliation: Department of Endocrinology and Diabetes (V.B.S., N.P., M.N.C., E.A.D., T.W.J.), Princess Margaret Hospital for Children, Perth, Western Australia 6840, Australia; and School of Paediatrics and Child Health (V.B.S., E.A.D., T.W.J.), School of Sport Science, Exercise, and Health (P.A.F.), and Telethon Kids Institute, The Centre for Child Health Research (R.J.D., A.J.R., N.P., H.C.R., M.N.C., E.A.D., T.W.J.), The University of Western Australia, Perth, Western Australia 6008, Australia.
authors.forename: Paul A
authors.initials: PA
authors.lastname: Fournier
authors.affiliation: Department of Endocrinology and Diabetes (V.B.S., N.P., M.N.C., E.A.D., T.W.J.), Princess Margaret Hospital for Children, Perth, Western Australia 6840, Australia; and School of Paediatrics and Child Health (V.B.S., E.A.D., T.W.J.), School of Sport Science, Exercise, and Health (P.A.F.), and Telethon Kids Institute, The Centre for Child Health Research (R.J.D., A.J.R., N.P., H.C.R., M.N.C., E.A.D., T.W.J.), The University of Western Australia, Perth, Western Australia 6008, Australia.
authors.forename: Raymond J
authors.initials: RJ
authors.lastname: Davey
authors.affiliation: Department of Endocrinology and Diabetes (V.B.S., N.P., M.N.C., E.A.D., T.W.J.), Princess Margaret Hospital for Children, Perth, Western Australia 6840, Australia; and School of Paediatrics and Child Health (V.B.S., E.A.D., T.W.J.), School of Sport Science, Exercise, and Health (P.A.F.), and Telethon Kids Institute, The Centre for Child Health Research (R.J.D., A.J.R., N.P., H.C.R., M.N.C., E.A.D., T.W.J.), The University of Western Australia, Perth, Western Australia 6008, Australia.
authors.forename: Adam J
authors.initials: AJ
authors.lastname: Retterath
authors.affiliation: Department of Endocrinology and Diabetes (V.B.S., N.P., M.N.C., E.A.D., T.W.J.), Princess Margaret Hospital for Children, Perth, Western Australia 6840, Australia; and School of Paediatrics and Child Health (V.B.S., E.A.D., T.W.J.), School of Sport Science, Exercise, and Health (P.A.F.), and Telethon Kids Institute, The Centre for Child Health Research (R.J.D., A.J.R., N.P., H.C.R., M.N.C., E.A.D., T.W.J.), The University of Western Australia, Perth, Western Australia 6008, Australia.
authors.forename: Nirubasini
authors.initials: N
authors.lastname: Paramalingam
authors.affiliation: Department of Endocrinology and Diabetes (V.B.S., N.P., M.N.C., E.A.D., T.W.J.), Princess Margaret Hospital for Children, Perth, Western Australia 6840, Australia; and School of Paediatrics and Child Health (V.B.S., E.A.D., T.W.J.), School of Sport Science, Exercise, and Health (P.A.F.), and Telethon Kids Institute, The Centre for Child Health Research (R.J.D., A.J.R., N.P., H.C.R., M.N.C., E.A.D., T.W.J.), The University of Western Australia, Perth, Western Australia 6008, Australia.
authors.forename: Heather C
authors.initials: HC
authors.lastname: Roby
authors.affiliation: Department of Endocrinology and Diabetes (V.B.S., N.P., M.N.C., E.A.D., T.W.J.), Princess Margaret Hospital for Children, Perth, Western Australia 6840, Australia; and School of Paediatrics and Child Health (V.B.S., E.A.D., T.W.J.), School of Sport Science, Exercise, and Health (P.A.F.), and Telethon Kids Institute, The Centre for Child Health Research (R.J.D., A.J.R., N.P., H.C.R., M.N.C., E.A.D., T.W.J.), The University of Western Australia, Perth, Western Australia 6008, Australia.
authors.forename: Matthew N
authors.initials: MN
authors.lastname: Cooper
authors.affiliation: Department of Endocrinology and Diabetes (V.B.S., N.P., M.N.C., E.A.D., T.W.J.), Princess Margaret Hospital for Children, Perth, Western Australia 6840, Australia; and School of Paediatrics and Child Health (V.B.S., E.A.D., T.W.J.), School of Sport Science, Exercise, and Health (P.A.F.), and Telethon Kids Institute, The Centre for Child Health Research (R.J.D., A.J.R., N.P., H.C.R., M.N.C., E.A.D., T.W.J.), The University of Western Australia, Perth, Western Australia 6008, Australia.
authors.forename: Elizabeth A
authors.initials: EA
authors.lastname: Davis
authors.affiliation: Department of Endocrinology and Diabetes (V.B.S., N.P., M.N.C., E.A.D., T.W.J.), Princess Margaret Hospital for Children, Perth, Western Australia 6840, Australia; and School of Paediatrics and Child Health (V.B.S., E.A.D., T.W.J.), School of Sport Science, Exercise, and Health (P.A.F.), and Telethon Kids Institute, The Centre for Child Health Research (R.J.D., A.J.R., N.P., H.C.R., M.N.C., E.A.D., T.W.J.), The University of Western Australia, Perth, Western Australia 6008, Australia.
authors.forename: Timothy W
authors.initials: TW
authors.lastname: Jones
mesh_terms: D000293:Adolescent; D000328:Adult; D001786:Blood Glucose / Q000032:analysis*; D003922:Diabetes Mellitus, Type 1 / Q000097:blood*; D004032:Diet; D015444:Exercise / Q000502:physiology*; D005260:Female; D005947:Glucose / Q000008:administration & dosage*; D015309:Glucose Clamp Technique; D006442:Glycated Hemoglobin / Q000032:analysis; D006801:Humans; D007003:Hypoglycemia / Q000097:blood; D007328:Insulin / Q000008:administration & dosage; D007700:Kinetics; D019344:Lactic Acid / Q000097:blood; D008297:Male; D010101:Oxygen Consumption; D055815:Young Adult
chemical_list: D001786:Blood Glucose; D005947:Glucose; D006442:Glycated Hemoglobin; D007328:Insulin; D019344:Lactic Acid