Introduction: There are different theories about cellular and molecular mechanisms of adaptation to changes in fat tissue as a result of practice. One of the most recent theories is Irisin hormone. This theory states that during exercise, the skeletal muscle secretes a myokines that is called irisin, which triggers weight loss through affecting white and brown adipose tissue. This study aimed to investigate the effects of eight week of high intensity interval training types (HIIT) on serum Irisin in obese women aged between 25 and 35.
Methodology: 42 volunteer obese women were selected randomly and divided into three groups: control group, the first experimental group (HIIT1),(20) people, and the second experimental group (HIIT2) (20). Participants had a fasting blood test one day before and 48 hours after exercise. The experimental group HIIT1 did a one-minute activity three times with four minutes rest between sets. Each twelve-minute exercise session consisted of 6 one-minute repeats at 90% heart rate reserve and 6 one-minute repeats at 50% of the HRR. The experimental group HIIT2 carried out their thirty-second activity four times with a four-minute rest after every 4 minutes. Each activity session lasted for 9 minutes that included 9 repeats of a thirty-second activity at 90 percent of HRR and 9 repeats of a thirty-second activity at 50% HRR. Both experimental groups had a ten-minute warm-up and a five-minute cool-down.
Results: K-S test was used for normality and one-way ANOVA was employed to compare means of the three groups, Turkey’s test was also used due to the significant difference between the groups The results showed that eight weeks of HIIT implementation resulted in a significant increase in serum Irisin of group HIIT1 (047/0 = p) and group HIIT2 (041/0 = p).
Conclusion: Eight weeks of HIIT causes an increase in serum Irisin of obese women.