Six months of aerobic exercise does not improve microvascular function in type 2 diabetes mellitus.
OBJECTIVE
Adults with type 2 diabetes mellitus have impaired microvascular function. It has been hypothesised that microvascular function may be restored through regular exercise. The aim of this study was to investigate whether 6 months of regular aerobic exercise would improve microvascular function in adults with type 2 diabetes.


METHODS
Fifty-nine patients with type 2 diabetes (32 males, age 62.9+/-7.6 years, HbA(1c) 6.8+/-0.9%) were randomised to either a 6-month aerobic exercise programme (30 min, three times a week, 70-80% of maximal heart rate) or a 'standard care' control group. Before and after the intervention period, microvascular function was assessed as the maximum skin hyperaemia to local heating and endothelial and non-endothelial responsiveness following the iontophoretic application of acetylcholine and sodium nitroprusside. Maximal oxygen uptake, as an index of aerobic fitness, was assessed using a maximal exercise test.


RESULTS
No significant improvement was seen in the exercise group compared with the control group for any of the variables measured: maximal oxygen uptake (control pre: 1.73+/-0.53 [means+/-SD] vs post: 1.67+/-0.40; exercise pre: 1.75+/-0.56 vs post: 1.87+/-0.62 l/min, p=0.10); insulin sensitivity (insulin tolerance test) (control pre: -0.17+/-0.06 vs post: -0.17+/-0.06; exercise pre: -0.16+/-0.1 vs post: -0.17+/-0.07 mmol l(-1) min(-1), p=0.97); maximal hyperaemia (control pre: 1.49+/-0.43 vs post: 1.52+/-0.57; exercise pre: 1.42+/-0.36 vs post: 1.47+/-0.33 V, p=0.85); peak response to acetylcholine (control pre: 1.37+/-0.47 vs post: 1.28+/-0.37; exercise pre: 1.27+/-0.44 vs post: 1.44+/-0.23 V, p=0.19) or to sodium nitroprusside (control pre: 1.09+/-0.50 vs post: 1.10+/-0.39; exercise pre: 1.12+/-0.28 vs post: 1.13+/-0.40 V, p=0.98).


CONCLUSIONS
In this group of type 2 diabetic patients with good glycaemic control a 6-month aerobic exercise programme did not improve microvascular function or aerobic fitness.
Middlebrooke
A R
AR
Children's Health and Exercise Research Centre, School of Sport and Health Sciences, University of Exeter, Exeter, UK. a.r.middlebrooke@exeter.ac.uk
Elston
L M
LM
Macleod
K M
KM
Mawson
D M
DM
Ball
C I
CI
Shore
A C
AC
Tooke
J E
JE
D000328:Adult; D017668:Age of Onset; D000368:Aged; D001786:Blood Glucose / Q000378:metabolism; D003924:Diabetes Mellitus, Type 2 / Q000097:blood / Q000503:physiopathology*; D003925:Diabetic Angiopathies / Q000503:physiopathology* / Q000517:prevention & control; D015444:Exercise / Q000502:physiology*; D006442:Glycated Hemoglobin / Q000032:analysis; D006801:Humans; D008833:Microcirculation / Q000502:physiology*; D008875:Middle Aged; D010101:Oxygen Consumption; D010349:Patient Compliance; D012885:Skinfold Thickness; D012907:Smoking
D001786:Blood Glucose; D006442:Glycated Hemoglobin