The goal of this observational quasi-experimental study is to evaluate whether a single session of high-intensity interval training (HIIT) can acutely modulate metabolic markers, particularly adiponectin isoforms, in insufficiently active young adults (men and women, 18-29 years, free of cardiometabolic disease).

The main questions it aims to answer are:

Does a single HIIT session increase circulating medium- and high-molecular-weight adiponectin?

Does HIIT acutely alter lipid and glucose metabolism markers such as non-HDL cholesterol, insulin, and lactate?

Participants completed the following tasks:

Underwent baseline assessments (anthropometry, body composition, and resting cardiovascular parameters).

Performed one HIIT session consisting of six 3-minute intervals at 80% heart rate reserve, each followed by 3 minutes of active recovery.

Provided blood samples before and immediately after exercise to analyze adiponectin isoforms (LMW, MMW, HMW) via Western blot and to measure glucose, insulin, lipid profile, liver enzymes, and lactate.

Summary of findings:

A single HIIT session significantly increased medium-molecular-weight adiponectin (~19%), decreased the HMW/MMW ratio, and elevated lactate and non-HDL cholesterol. No significant changes were observed in LMW or HMW adiponectin. These results suggest that MMW adiponectin is an early, sensitive marker of acute exercise response in sedentary young adults, though further research is needed to confirm long-term implications

Inclusion Criteria:

• Age between 18 and 29 years
• Engage in less than 150 minutes of moderate-intensity or 75 minutes of vigorous-intensity physical activity per week)
• Having no positive responses on the PAR-Q & YOU questionnaire

Exclusion Criteria:

• Diagnosis of cardiometabolic disease
• Use of anti-inflammatory treatment during the week prior to participation