Effects of Whole-Body HIIT and Moderate Continuous Exercise on Immune Function

This study was designed as a two-arm, parallel-group, randomized controlled trial. A total of 20 recreationally active male participants were randomly assigned to either the Whole Body High-Intensity Interval Training (WB-HIIT) group or the Moderate-Intensity Continuous Training (MICT) group. The intervention lasted 12 weeks and involved supervised training sessions multiple times a week.

The WB-HIIT protocol consisted of repeated high-intensity whole-body exercises performed at near-maximum effort with intermittent rest periods, while the MICT group performed moderate-intensity continuous aerobic exercise. Immune function was assessed through selected hematological and biochemical markers collected at baseline and post-intervention. In addition, physical performance variables were evaluated to examine secondary adaptations to different exercise modalities. The primary aim of the study was to compare the effects of WB-HIIT and MICT on immune system responses, while secondary outcomes included changes in exercise performance. This study provides insights into how different training intensities affect immune regulation in individuals who are active in their leisure time.

Inclusion criteria

Healthy male adults Aged 18-25 years Not engaged in regular structured exercise training (>3 sessions/week) VO₂max within normal healthy range Willingness to participate and provide informed consent No acute or chronic inflammatory, metabolic, or cardiovascular disease

Exclusion criteria

Female participants (not included in study design) Smoking or alcohol abuse Use of anti-inflammatory or immunomodulatory drugs Participation in regular high-intensity training programs Musculoskeletal limitations preventing exercise testing or training Acute infection within last 2 weeks Chronic metabolic, cardiovascular, or autoimmune diseases