Sprint training increases muscle oxidative metabolism during high-intensity exercise in patients with type 1 diabetes.
OBJECTIVE
To investigate sprint-training effects on muscle metabolism during exercise in subjects with (type 1 diabetic group) and without (control group) type 1 diabetes.


METHODS
Eight subjects with type 1 diabetes and seven control subjects, matched for age, BMI, and maximum oxygen uptake (Vo(2peak)), undertook 7 weeks of sprint training. Pretraining, subjects cycled to exhaustion at 130% Vo(2peak). Posttraining subjects performed an identical test. Vastus lateralis biopsies at rest and immediately after exercise were assayed for metabolites, high-energy phosphates, and enzymes. Arterialized venous blood drawn at rest and after exercise was analyzed for lactate and [H(+)]. Respiratory measures were obtained on separate days during identical tests and during submaximal tests before and after training.


RESULTS
Pretraining, maximal resting activities of hexokinase, citrate synthase, and pyruvate dehydrogenase did not differ between groups. Muscle lactate accumulation with exercise was higher in type 1 diabetic than nondiabetic subjects and corresponded to indexes of glycemia (A1C, fasting plasma glucose); however, glycogenolytic and glycolytic rates were similar. Posttraining, at rest, hexokinase activity increased in type 1 diabetic subjects; in both groups, citrate synthase activity increased and pyruvate dehydrogenase activity decreased; during submaximal exercise, fat oxidation was higher; and during intense exercise, peak ventilation and carbon dioxide output, plasma lactate and [H(+)], muscle lactate, glycogenolytic and glycolytic rates, and ATP degradation were lower in both groups.


CONCLUSIONS
High-intensity exercise training was well tolerated, reduced metabolic destabilization (of lactate, H(+), glycogenolysis/glycolysis, and ATP) during intense exercise, and enhanced muscle oxidative metabolism in young adults with type 1 diabetes. The latter may have clinically important health benefits.
Harmer
Alison R
AR
1Discipline of Physiotherapy, University of Sydney, Lidcombe, New South Wales, Australia. a.harmer@usyd.edu.au
Chisholm
Donald J
DJ
McKenna
Michael J
MJ
Hunter
Sandra K
SK
Ruell
Patricia A
PA
Naylor
Justine M
JM
Maxwell
Lyndal J
LJ
Flack
Jeff R
JR
D000328:Adult; D001786:Blood Glucose / Q000378:metabolism; D003922:Diabetes Mellitus, Type 1 / Q000097:blood / Q000378:metabolism* / Q000503:physiopathology; D015444:Exercise / Q000502:physiology*; D005080:Exercise Test; D005260:Female; D006801:Humans; D008297:Male; D018482:Muscle, Skeletal / Q000378:metabolism*; D010101:Oxygen Consumption / Q000502:physiology*; D055815:Young Adult
D001786:Blood Glucose