The effect of eight weeks high- intensity interval training alone and combined with resistance training on miR-33b expression in PBMCs of overweight/obese women

Background: The expression of microRNAs as epigenetic regulators of lipid metabolism pathways disrupt in obese condition, in this regard miR-33b has particular importance. Therefore, the present study was conducted to determine the effect of eight-week high- intensity interval training (HIIT) alone and combined with resistance training (CHRT) on miR-33b expression in overweight/ obese middle-aged women.

Methods: Twenty-four middle-aged overweight/obese women participated in two homogeneous HIIT (5 days/week, n=12) and CHRT (3 day/week HIIT with 2 day/week resistance training, n=12) groups for eight-week. The HIIT protocol consisted of alternating bouts of high-intensity exercise at 80%–85% of VO2max with active breaks at 60% of VO2max and resistance training protocol conducted to circuit-weight training with 75-80% of 1-RM. MiR-33b expression levels were measured by real time- PCR 48h before and after the training protocols.

Results: The miR-33b expression levels were increased in both groups but was significant only in the CHRT group (6.02 fold, p=0.002). However, there was no significant difference between miR-33b expression levels in two groups.

Conclusion: According to significant effect of CHRT on miR-33b expression as epigenetic lipid metabolism indicator, CHRT protocol can be considered as a non-pharmacological method for treatment of metabolic disorders associated with obesity.