The purpose of this study was to investigate the effects of a high-intensity interval training (HIIT) intervention on cardiorespiratory fitness (CRF) and cardiometabolic health in active male university students. The main question it aims to answer is: Does HIIT improves CRF and cardiometabolic outcomes, including blood pressure, lipid profile, and insulin resistance estimated using the homeostasis model assessment of insulin resistance (HOMA-IR). Researchers will compare HIIT (designed to experimental group) to non-training intervention (designed to control group) to see if the training program works to improve the cardiometabolic health status. The HIIT program consisted of three sessions per week for 9 weeks, comprising of three sets of six to eight 30-second running bouts performed at 100-110% of maximal aerobic speed (MAS), interspersed with 30-second active recovery runs at 50% MAS between bouts.
High-intensity interval training (HIIT) is a time-efficient exercise strategy for improving physical fitness. However, limited evidence is available regarding its effects on cardiometabolic health, including blood pressure, blood lipid profile, glucose metabolism, and insulin resistance, in healthy young adults. The purpose of this randomized controlled trial was to investigate the effects of a 9-week HIIT intervention on cardiorespiratory fitness (CRF), blood pressure, blood lipid profile, glucose, insulin, and insulin resistance estimated using the homeostasis model assessment of insulin resistance (HOMA-IR) in physically active male university students. Twenty-nine healthy male students at the High Institute of Sport and Physical Education of Kef (Tunisia) were randomly assigned to either the HIIT group (HIITG, n=15) or the control group (CG, n=14). The HIIT group completed a supervised training program consisting of three sessions per week for 9 weeks, comprising of three sets of six to eight 30-second running bouts performed at 100-110% of maximal aerobic speed (MAS), interspersed with 30-second active recovery runs at 50% MAS between bouts. Outcome assessments were performed before and after the intervention. Cardiorespiratory fitness was evaluated by maximal oxygen consumption (VO₂max) and maximal aerobic speed (MAS) using the Vameval incremental running test. Cardiometabolic outcomes included systolic and diastolic blood pressure, total cholesterol, triglycerides, high-density lipoprotein cholesterol (HDL-C), low-density lipoprotein cholesterol (LDL-C), fasting glucose, fasting insulin, and insulin resistance estimated using the homeostasis model assessment of insulin resistance (HOMA-IR).
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
PREVENTION
Masking
NONE
Enrollment
29
The HIIT program consisted of three sessions per week for 9 weeks, comprising of three sets of sixr to eight bouts of 30-second runs at high intensity \[100-110% of maximal aerobic speed (MAS)\], interspersed with 30-second recovery runs at low intensity (50% MAS) between bouts.
Tunisia
El Kef, Boulifa, Tunisia
Insulin resistance
Insulin resistance was estimated by the homeostasis model assessment (HOMA-IR) index as HOMA-IR = (fasting insulin (mU/l) × fasting glucose (mmol/l) / 22.5)) (Matthews et al., 1985).
Time frame: One day before the start and two days after the completion of the 09 weeks of training program.
Total cholesterol
Total cholesterol concentration, expressed in mg/dL, was assessed by the enzymatic method on an Architect C8000 auto analyzer (Abbott Laboratories, Abbott Park, IL) using respective reagent kits.
Time frame: One day before the start and two days after the completion of the 09 weeks of training program.
Triglyceride
Triglyceride concentration, expressed in mg/dL, was assessed by the enzymatic method on an Architect C8000 auto analyzer (Abbott Laboratories, Abbott Park, IL) using respective reagent kits.
Time frame: One day before the start and two days after the completion of the 09 weeks of training program.
Blood pressure
Blood pressure, expressed in mmHg, was measured after 15 minutes of seated rest using an automatic blood pressure monitor (Omron BP652; Omron Healthcare Inc., Vernon Hills, IL, USA).
Time frame: One day before the start and two days after the completion of the 09 weeks of training program
Cardiorespiratory fitness
Cardiorespiratory fitness was assessed using the Vameval incremental running test performed to exhaustion (Cazorla, 1999). Maximal aerobic speed (MAS) was determined from the highest running speed achieved during the test, and maximal oxygen consumption (VO2max) was estimated using the standard Vameval protocol (Cazorla, 1999). The Vameval test is a validated field test for assessing aerobic capacity in healthy young adults.
Time frame: One day before the start and two days after the completion of the 09 weeks of training program.
Body mass index
Body mass index (BMI), expressed in kg/m², was calculated from measured body mass (kg) and height (m) using the standard formula: BMI = body mass (kg) / height² (m²). Body mass and height were used only to derive BMI and were not considered separate outcome measures.
Time frame: One day before the start and two days after the completion of the 09 weeks of training program
Body fat percentage
Body fat percentage (%) was estimated from four skinfold measurements (bicipital, triceps, subscapular, and suprailiac) using the Durnin and Womersley (1973) method.
Time frame: One day before the start and two days after the completion of the 09 weeks of training program.
Fasting glucose
Fasting glucose concentration, expressed in mg/dL, was assessed by the enzymatic method on an Architect C8000 auto analyzer (Abbott Laboratories, Abbott Park, IL) using respective reagent kits.
Time frame: One day before the start and two days after the completion of the 09 weeks of training program.
Insulin
Insulin concentration, expressed in µU/mL, was measured by chemiluminescence immunoassay using a Liaison analyzer and the respective reagents kit (DiaSorin Inc., Stillwater, MN, USA).
Time frame: One day before the start and two days after the completion of the 09 weeks of training program.
High-density lipoprotein cholesterol
High-density lipoprotein cholesterol, expressed in mg/dL, was assessed by the enzymatic method on an Architect C8000 auto analyzer (Abbott Laboratories, Abbott Park, IL) using respective reagent kits.
Time frame: One day before the start and two days after the completion of the 09 weeks of training program.
Low-density lipoprotein cholesterol
Low-density lipoprotein cholesterol, expressed in mg/dL, was calculated using the Friedewald formula (Friedewald et al., 1972).
Time frame: One day before the start and two days after the completion of the 09 weeks of training program
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