Impact of aerobic versus resistance exercise training on glucose control and biomarkers of oxidative stress among Saudi patients with type 2 diabetes

Oxidative stress is usually associated with diabetes as a result of abnormal glucose control [4-7].However, oxidative stress is one of the main cause of diabetic complications [811]. In the other hand, metabolic control enhance antioxidant defense system in type 2 diabetes patients (T2DM) [12]. Hyperglycemia seems to cause an imbalance between oxidant and antioxidant systems in T2DM patients [13].

Impact of aerobic versus resistance exercise training on glucose control and biomarkers of oxidative stress among Saudi patients with type 2 diabetes www.arjonline.org

Subjects
One hundred obese T2DM patients, their age mean was 49.71 ± 6.28 year and their body mass index (BMI) mean was 32.87±3.12 Kg/m2. Smoking, renal failure, heart failure, respiratory failure, hepatitis and pregnancy were the exclusion criteria. Participants were assigned into two groups; group (A) received aerobic exercise training on treadmill. While, group (B) received resisted exercise training. Informed written consent was signed by all participants.

B. Measurement of oxidative stress markers and anti-
oxidant status: Plasma level of malondialdehyde (MDA) was measured by the method described by Esterbauer et al [26]. Glutathione (GSH) level was measured by adopting the method described by Weckbecker and Cory [27], glutathione peroxidase (GPx) and superoxide dismutase (SOD) were was estimated according the method described by Masnini [28].  [29]. Participants conducted training intensity of 60-80% of maximum heart rate for 30 minutes, 3 sessions/week.

Group (B)
received resistance exercises on some resistance gym machines (Nautilus Sports/Medical Industries, Independence, VA). Participants conducted training intensity of 60 and 80% of their one maximal repetition weight (1-RM) for 30 minutes, 3 sessions/week [30].

Results
The baseline characteristics of the participants revealed no significant differences between both groups as shown in table (1).

Group (A) Group (B) Significance
Age (  Impact of aerobic versus resistance exercise training on glucose control and biomarkers of oxidative stress among Saudi patients with type 2 diabetes www.arjonline.org The mean values of MDA, SOD and HOMA-IR were significantly decreased, while the mean values of GSH, GPx and QUICKI were significantly increased in patients of group (A) as a result of aerobic exercise training and group (B) as a result of resisted exercise training (Table 2 and 3). However, there were significant differences between mean levels of the investigated parameters in group (A) and group (B) after treatment with more changes in patients received aerobic exercise training (Table 4). MDA: Malondialdehyde; GSH: Glutathione; GPX: Glutathione peroxidase; SOD: Superoxide dismutase; QUICKI: The quantitative insulin-sensitivity check index; HOMA-IR: Homeostasis Model Assessment-Insulin Resistance Index; (*) indicates a significant difference, P < 0.05.

Discussion
Oxidative stress (OS) plays a major role in pathogenesis of T2DM complications [31,32]. Therefore this study was designed to examine aerobic versus resisted exercise training effects upon insulin resistance and oxidative stress markers among T2DM patients.
Concerning insulin resistance, both aerobic exercise and resisted exercise training significantly improved insulin resistance, these results agreed with Bacchi et al. stated that 4 months of aerobic and resistance exercises improved insulin sensitivity in T2DM with nonalcoholic fatty liver [33]. However, Angelico et al. reported that 5%-10% weight loss of patients with metabolic syndrome modulated insulin resistance [34].
Concerning oxidative stress, results of the present study proved that both aerobic and resistance exercises mean values of MDA, SOD and HOMA-IR were significantly decreased, while the mean values of GSH, GPx and QUICKI were significantly increased in T2DM patients. These results agreed with previous studies that stated that 6 months of aerobic exercise increased GSH in T2DM individuals [35,36]. However, another study reported that 24 weeks of resistance exercise ameliorated oxidative stress in obese individuals [37]. In addition, Oliveira et al. confirmed that 4 months of aerobic exercise improved oxidative stress markers among T2DM subjects [38]. However, Vinetti et al. found that 12 months of combined aerobic, resistance and flexibility training modulated oxidative stress among T2DM patients [39]. While, Farinha et al. mentioned that 3 months of treadmill exercise improved oxidative stress in women with metabolic syndrome [40]. Similarly, Nojima et al. stated that 12 months of aerobic exercise improved metabolic control and oxidative stress markers among T2DM patients [41]. Moreover, Gordon et al. proved that 3 months of Hatha yoga exercise improved glucose control, blood lipid profile and oxidative stress markers among T2DM patients [42]. The possible mechanisms for modulation of oxidative stress markers following exercise training may include improvement in glucose control [43][44][45][46], also improved insulin sensitivity in target tissues is the second possible mechanism for reduction in oxidative stress by aerobic and resistance exercise training [47,48].

Conclusion
Aerobic exercise is more appropriate than resisted exercise training in modulating insulin resistance and oxidative stress among type 2 diabetic patients.