title: Effect of intermittent high-intensity compared with continuous moderate exercise on glucose production and utilization in individuals with type 1 diabetes.
abstract: Previously, the decline in glycemia in individuals with type 1 diabetes has been shown to be less with intermittent high-intensity exercise (IHE) compared with continuous moderate-intensity exercise (MOD) despite the performance of a greater amount of total work. The purpose of the present study was to determine whether this lesser decline in glycemia can be attributed to a greater increment in endogenous glucose production (Ra) or attenuated glucose utilization (Rd). Nine individuals with type 1 diabetes were tested on two separate occasions, during which either a 30-min MOD or IHE protocol was performed under conditions of a euglycemic clamp in combination with the infusion of [6,6-(2)H]glucose. MOD consisted of continuous cycling at 40% VO2 peak, whereas IHE involved a combination of continuous exercise at 40% VO2 peak interspersed with additional 4-s maximal sprint efforts performed every 2 min to simulate the activity patterns of intermittent sports. During IHE, glucose Ra increased earlier and to a greater extent compared with MOD. Similarly, glucose Rd increased sooner during IHE, but the increase by the end of exercise was comparable with that elicited by MOD. During early recovery from IHE, Rd rapidly declined, whereas it remained elevated after MOD, a finding consistent with a lower glucose infusion rate during early recovery from IHE compared with MOD (P<0.05). The results suggest that the lesser decline in glycemia with IHE may be attributed to a greater increment in Ra during exercise and attenuated Rd during exercise and early recovery.
authors.affiliation: School of Human Movement and Exercise Science, University of Western Australia, 35 Stirling Highway, Crawley, and Department of Endocrinology and Diabetes, Princess Margaret Hospital, Subiaco, Western Australia, 6009, Australia. kym.guelfi@uwa.edu.au
authors.forename: K J
authors.initials: KJ
authors.lastname: Guelfi
authors.forename: N
authors.initials: N
authors.lastname: Ratnam
authors.forename: G A
authors.initials: GA
authors.lastname: Smythe
authors.forename: T W
authors.initials: TW
authors.lastname: Jones
authors.forename: P A
authors.initials: PA
authors.lastname: Fournier
mesh_terms: D000293:Adolescent; D000328:Adult; D001786:Blood Glucose / Q000378:metabolism; D003922:Diabetes Mellitus, Type 1 / Q000097:blood / Q000378:metabolism*; D015444:Exercise; D005260:Female; D005947:Glucose / Q000378:metabolism*; D015309:Glucose Clamp Technique; D006339:Heart Rate; D006728:Hormones / Q000097:blood; D006801:Humans; D019344:Lactic Acid / Q000097:blood; D008297:Male; D010101:Oxygen Consumption
chemical_list: D001786:Blood Glucose; D006728:Hormones; D019344:Lactic Acid; D005947:Glucose