RT Journal Article
SR Electronic
T1 Effects of Exercise Training Intensity on Pancreatic β-Cell Function
JF Diabetes Care
JO Diabetes Care
FD American Diabetes Association
SP 1807
OP 1811
DO 10.2337/dc09-0032
VO 32
IS 10
A1 Slentz, Cris A.
A1 Tanner, Charles J.
A1 Bateman, Lori A.
A1 Durheim, Michael T.
A1 Huffman, Kim M.
A1 Houmard, Joseph A.
A1 Kraus, William E.
YR 2009
UL http://care.diabetesjournals.org/content/32/10/1807.abstract
AB OBJECTIVE Insulin resistance and β-cell dysfunction both are important contributors to the pathogenesis of type 2 diabetes. Exercise training improves insulin sensitivity, but its effects on β-cell function are less well studied. RESEARCH DESIGN AND METHODS Sedentary, overweight adults were randomized to control or one of three 8-month exercise programs: 1) low amount/moderate intensity, 2) low amount/vigorous intensity, or 3) high amount/vigorous intensity. Of 387 randomized, 260 completed the study and 237 had complete data. Insulin sensitivity (Si), acute insulin response to glucose (AIRg), and the disposition index (DI = Si × AIRg) were modeled from an intravenous glucose tolerance test. RESULTS Compared with control subjects, all three training programs led to increases in DI. However, the moderate-intensity group experienced a significantly larger increase in DI than either of the vigorous-intensity groups and through a different mechanism. The high-amount/vigorous-intensity group improved Si and had a compensatory reduction in AIRg, whereas the moderate-intensity group had a similar improvement in Si but almost no reduction in AIRg. Importantly, the inactive control group experienced a significant increase in fasting glucose. CONCLUSIONS To the extent that the DI accurately reflects β-cell function, we observed that both moderate- and vigorous-intensity exercise training improved β-cell function, albeit through distinct mechanisms. It is not clear which of these mechanisms is preferable for maintenance of metabolic health. While moderate-intensity exercise led to a larger improvement in DI, which may reflect a transition toward a more normal DI, longer-term investigations would be necessary to determine which was more effective at reducing diabetes risk. © 2009 by the American Diabetes Association.