Adding resistance training to aerobics fails to further benefit diabetes patients
MedWire News: Adding resistance training to high frequency aerobic exercises does not provide any additional benefit in reducing risk for diabetes complications in obese Type 2 diabetes patients, say researchers.
Although combined aerobic and resistance training (ART) is equally as effective in enhancing weight loss as aerobic training (AT) alone, it exerts less positive effects on insulin sensitivity, endothelial factors, adipokines, and pro-inflammatory marker release, they report.
PierMarco Piatti (San Raffaele Scientific Institute, Milan, Italy) and team randomly assigned 47 Type 2 diabetes patients to participate in either an aerobic exercise group (n=27) or an aerobic plus resistance exercise group (n=20).
Both exercise programs lasted 3 weeks and were conducted alongside similar hypocaloric diets.
As reported in the journal Diabetes Research and Clinical Practice, the authors found that the exercise programs equally improved body weight and fructosamine levels after 21 days of exercise.
However, ART reduced insulin resistance to a lesser degree than AT, at a 25% versus 54% reduction in Homeostasis Model Assessment (HOMA) index.
The research team also found that ART seemed to have a pro-inflammatory effect.
Adiponectin levels increased by 54% after AT, whereas they decreased by 13% after ART.
Conversely, tumor necrosis factor (TNF)-α, resistin, matrix metalloproteinase-2, and monocyte chemoattractan protein-1 levels were all significantly decreased after AT but increased after ART.
"A possible explanation of the differences between AT and ART trainings on adiponectin levels could be related to the fact that TNF-α were higher in ART than in AT and it [has previously been] demonstrated that TNF-α down-regulates adiponectin levels in vivo," suggest the authors.
Furthermore, they report decreases in mean blood pressure and endothelin (ET)-1 incremental areas during the walking test after AT (by 3.6 mmHg and 11%, respectively), but increases in both measurements after ART (by 0.6 mmHg and 30%, respectively).
"The addition of resistance to aerobic high frequency exercise may have a deleterious effect over endothelial function and hemodynamic balance through a stimulation of ET-1 release and a concomitant increase in mean blood pressure levels," suggest Piatti and team.
Even if ART remains an important tool in the therapy of obese Type 2 diabetes patients, the duration and frequency of ART may adversely impact its beneficial effects by inducing a more pro-inflammatory pathway, they add.
"The negative results of combined ART exercise on sequential days achieved in the present study strongly support American College of Sports Medicine and American Diabetes Association guidelines suggesting that such patients should exercise on alternate days," they conclude.
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By Sally Robertson