Increased Daily Walking Improves Lipid Oxidation Without Changes in Mitochondrial Function in Type 2 Diabetes

  1. Michael I. Trenell, PHD1,2,
  2. Kieren G. Hollingsworth, PHD2,
  3. Ee Lin Lim, MRCP1,2 and
  4. Roy Taylor, MD1,2
  1. 1Diabetes Research Group, Institute of Cellular Medicine, Newcastle University, Newcastle upon Tyne, U.K
  2. 2Newcastle Magnetic Resonance Centre, Newcastle University, Newcastle upon Tyne, U.K
  1. Corresponding author: Dr. Michael Trenell, m.i.trenell{at}ncl.ac.uk

Abstract

OBJECTIVE—To determine whether increased daily physical activity improves mitochondrial function and/or lipid oxidation in type 2 diabetes.

RESEARCH DESIGN AND METHODS—Volunteers with (n = 10) and without (n = 10) type 2 diabetes were matched for habitual physical activity, age, sex, and weight. Basal and maximal mitochondrial activity, physical activity, and resting substrate oxidation were measured at baseline and after 2 and 8 weeks of increased physical activity.

RESULTS—Baseline physical activity (6,450 ± 851 vs. 7,638 ± 741 steps/day), basal ATP use (12 ± 1 vs. 12 ± 1 μmol · ml−1 · min−1), phosphocreatine recovery from exercise (31 ± 5 vs. 29 ± 3 s), and basal lipid oxidation (0.57 ± 0.07 vs. 0.65 ± 0.06 mg · kg body wt−1 · min−1) were similar in people with and without type 2 diabetes. There was a significant increase in physical activity after 8 weeks (12,322 ± 1,979 vs. 9,187 ± 1,159 steps/day, respectively). Following increased physical activity, there were no changes in basal ATP use or phosphocreatine recovery after exercise in either group. Basal lipid oxidation increased after 8 weeks of increased physical activity in people with type 2 diabetes (0.79 ± 0.08 mg · kg−1 · min−1) but not people without (0.68 ± 0.13 mg · kg body wt−1 · min−1).

CONCLUSIONS—Resting and maximal ATP turnover are not impaired in people with well-controlled type 2 diabetes compared with control subjects matched for physical activity as well as age and weight. Increased unsupervised daily physical activity is sustainable and improves lipid oxidation independent of change in mitochondrial activity in people with type 2 diabetes.

Footnotes

  • Published ahead of print at http://care.diabetesjournals.org on 16 May 2008.

    Readers may use this article as long as the work is properly cited, the use is educational and not for profit, and the work is not altered. See http://creativecommons.org/licenses/by-nc-nd/3.0/ for details.

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    • Received February 11, 2008.
    • Accepted May 10, 2008.
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This Article

  1. Diabetes Care vol. 31 no. 8 1644-1649
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