title: Effects of sprint training on extrarenal potassium regulation with intense exercise in Type 1 diabetes.
abstract: Effects of sprint training on plasma K+ concentration ([K+]) regulation during intense exercise and on muscle Na+-K+-ATPase were investigated in subjects with Type 1 diabetes mellitus (T1D) under real-life conditions and in nondiabetic subjects (CON). Eight subjects with T1D and seven CON undertook 7 wk of sprint cycling training. Before training, subjects cycled to exhaustion at 130% peak O2 uptake. After training, identical work was performed. Arterialized venous blood was drawn at rest, during exercise, and at recovery and analyzed for plasma glucose, [K+], Na+ concentration ([Na+]), catecholamines, insulin, and glucagon. A vastus lateralis biopsy was obtained before and after training and assayed for Na+-K+-ATPase content ([3H]ouabain binding). Pretraining, Na+-K+-ATPase content and the rise in plasma [K+] ([K+]) during maximal exercise were similar in T1D and CON. However, after 60 min of recovery in T1D, plasma [K+], glucose, and glucagon/insulin were higher and plasma [Na+] was lower than in CON. Training increased Na+-K+-ATPase content and reduced [K+] in both groups (P < 0.05). These variables were correlated in CON (r = -0.65, P < 0.05) but not in T1D. This study showed first that mildly hypoinsulinemic subjects with T1D can safely undertake intense exercise with respect to K+ regulation; however, elevated [K+] will ensue in recovery unless insulin is administered. Second, sprint training improved K+ regulation during intense exercise in both T1D and CON groups; however, the lack of correlation between plasma delta[K+] and Na+-K+-ATPase content in T1D may indicate different relative contributions of K+-regulatory mechanisms.
authors.affiliation: School of Exercise and Sport Science, The University of Sydney, PO Box 170, Lidcombe, NSW, Australia 1825. A.Harmer@fhs.usyd.edu.au
authors.forename: Alison R
authors.initials: AR
authors.lastname: Harmer
authors.forename: Patricia A
authors.initials: PA
authors.lastname: Ruell
authors.forename: Michael J
authors.initials: MJ
authors.lastname: McKenna
authors.forename: Donald J
authors.initials: DJ
authors.lastname: Chisholm
authors.forename: Sandra K
authors.initials: SK
authors.lastname: Hunter
authors.forename: Jeanette M
authors.initials: JM
authors.lastname: Thom
authors.forename: Norman R
authors.initials: NR
authors.lastname: Morris
authors.forename: Jeff R
authors.initials: JR
authors.lastname: Flack
mesh_terms: D000222:Adaptation, Physiological; D000328:Adult; D003922:Diabetes Mellitus, Type 1 / Q000097:blood / Q000503:physiopathology*; D005260:Female; D006801:Humans; D007668:Kidney / Q000378:metabolism; D008297:Male; D018482:Muscle, Skeletal / Q000503:physiopathology*; D010807:Physical Endurance; D010809:Physical Fitness; D011188:Potassium / Q000097:blood*; D012420:Running; D000254:Sodium-Potassium-Exchanging ATPase / Q000378:metabolism*
chemical_list: D000254:Sodium-Potassium-Exchanging ATPase; D011188:Potassium