Effect of combined aerobic–resistance training and subsequent detraining on brain-derived neurotrophic factor (BDNF) and depression in women with type 2 diabetes mellitus: A randomized controlled trial

Abstract

Aims: In this study, we assessed the effects of a 12-week combined aerobic–resistance training and subsequent detraining on Beck Depression Inventory (BDI) score and mediating role of BDNF and also investigated whether exercise-induced alterations are maintained following a short period of detraining in women with type 2 diabetes (T2D). Materials and Methods: Thirty-four women with T2D were randomly assigned to experimental or control group (age: 60.6 ± 6.3, body mass index (BMI): 30.2 ± 1.3 kg/m2, HbA1c: 8.09 ± 0.73%). The exercise training comprised of combined aerobic–resistance programme (50%–70% heart rate reserve for aerobic exercise, and 50%–70% 1 repetition maximum for resistance exercise, respectively) performed three sessions per week over 12 weeks. The intervention period was followed by an 8-week detraining period. Data were collected at baseline and also following exercise intervention and detraining. Data were analysed by linear mixed model at p < 0.05. Results: After 12 weeks of combined exercise training and 8 weeks of detraining, there was a significant difference in BDNF (0.08; 95% confidence interval [CI] = 0.07–0.10; p = 0.001), fasting blood glucose (FBG) (−45.41; CI = −50.83, -39.98; p = 0.001), insulin (−6.47; CI = −7.04, −5.9; p = 0.001), HOMA-IR (−3.76; CI = −4.07, −3.45; p = 0.001) and BDI score (−17.17; CI = −20.29, −14.05; p = 0.001) between the experimental and control group. Multiple mediation analysis indicated that BDNF seems to have a mediating role in exercise-induced improvement of depression (p = 0.04). After the detraining period, BDI score remained unchanged and it showed a significant increase compared to before the start of training (p = 0.001). Conclusions: It may be concluded that exercise training improves depression that is likely to be explained by increased BDNF concentration in TD2. In spite of decreased BDNF concentration following an 8-week detraining, depression score was maintained.