Impacts of Resistance Training on Acute Secretion of Irisin in Obese Older and Young Adults
Condition: Obesity
MeSH terms: Obesity
Study type: Interventional

Summary: 
      It is established that resistance training improves metabolic health; however, the mechanisms
      of this process are not fully understood. A biologically active substance, irisin, has
      recently received interest in the scientific community with respect to its effects on energy
      expenditure and weight loss. The purpose of this study is to compare the different irisin
      release response during a resistance exercise training session. The study will compare
      individuals two different age groups (young adults: age 18-30; older adults: age 65-75)
      living with obesity.
    

Detailed description: 
      Background: Worldwide, the number of individuals living with obesity has doubled over the
      past thirty years. The growing prevalence of obesity is concerning as obesity is known to be
      one of the main risk factors for many chronic conditions, such as Type 2 diabetes and
      cardiovascular diseases. Therefore, it is important that the impact of different types of
      exercise are understood to properly prescribe exercise interventions to individuals living
      with obesity. Recently, there has been increased interest for a biologically active
      substances that are secreted during muscle contraction, myokines, regarding their effects on
      metabolism during exercise. Specifically, a novel myokine, named irisin, has caught the
      attention of numerous researchers. Irisin has been shown to play an important role in
      increasing energy expenditure, reducing body weight, and improving glucose metabolism by
      adipocyte metabolism. As of now, the majority of research has focused on irisin release
      during endurance activity; however, there is limited research on irisin secretion during
      resistance exercise training.

      Statement of Objectives: The purpose of this pilot study is to first determine whether irisin
      secretion increases during an acute session of resistance exercise training with obese
      individuals; and second, to determine whether changes in irisin levels during an acute bout
      of resistance exercise training can be seen in different age groups for obese individuals.

      Methodology: Fifteen young and fifteen old participants will be recruited via advertisement
      in the local newspaper, on radio stations, and on posters. Inclusion criteria include
      individuals aged between either 18-30 or 65-75 years old, classified as obese according to
      their BMI (>30 kg/m2), inactive defined as engaging in less than 150 minutes of moderate to
      vigorous aerobic exercise, not currently engaged in a resistance exercise training program,
      no previous diagnosis of Type 2 diabetes, and having no injuries or conditions that would
      prevent them from performing a resistance exercise training session.

      Primary Outcome Measure: The primary outcome measure in this study will be the change in
      irisin levels during resistance exercise training. A validated enzyme immunoassay kit from
      Phoenix Pharmaceutical Inc. (EK-067-16) will be used to measure irisin. Our group already has
      experience with this equipment and these procedures, which has been validated.

      Resistance Exercise Session: Participants will come for their first visit at which time they
      they will perform a test to determine their maximal strength [1-repetition maximal (1-RM)]
      for each exercise included in the program. During their second visit, participants will
      perform 10 different resistance exercises consisting of three sets of 8-10 repetitions, at
      80% of 1-RM. A 60-second rest will occur between sets. This exercise protocol was selected
      based on literature that suggests that the protocol and the intensity do not enhance
      mitochondria biogenesis. Also, this protocol was shown to be well tolerated by obese and
      older individuals.
    

Intervention name(s): Resistance Training Intervention
Intervention type(s): Behavioral
Intervention description(s): Participants will perform 10 different resistance exercises consisting of three sets of 8-10 repetitions, at 80% of 1-RM, separated by 60-second rest intervals between sets. This exercise protocol was chosen based on literature that suggests that the protocol and intensity do not enhance mitochondria biogenesis. Also, it was well tolerated by obese and older individuals.
Allocation: Non-Randomized
Intervention model: Parallel Assignment
Masking: None (Open Label)
Primary purpose: Prevention
Keywords: Irisin; Obesity; Resistance Training; Older Adults; Younger Adults; Myokines