Article - Eight weeks of high-intensity interval vs. sprint interval training effects on overweight and obese adolescents carried out during the cool-down period of physical education classes: randomized controlled trial.

Plain Language Summary

Obesity in children and adolescents is a global health issue, with increasing prevalence. Numerous studies have shown that levels of physical activity decrease during childhood and adolescence, reaching high rates of physically inactive children and adolescents. This study aimed to evaluate the effect of sprint interval training (SIT) and high-intensity interval training (HIIT) during the cool-down period of physical education classes on body composition, blood pressure variables (BP), pulse rate (PR), and cardiorespiratory fitness in overweight and obese adolescents. This study was a randomised controlled trial involving forty-five adolescents recruited from a high school. Participants were randomly assigned to three groups: SIT, HIIT, and a control group (maintaining regular physical education classes). Results showed that: - Both SIT and HIIT groups showed significant improvements in fat mass (FM) and trunk FM. - The HIIT group also demonstrated improvements in lean mass, blood pressure, systolic BP, diastolic BP, pulse rate, and VO2 max (cardiorespiratory fitness). - In contrast, the SIT group showed limited benefits, with changes observed only in FM. Authors concluded that performing a HIIT protocol during the cool-down period of physical education classes led to positive adaptations in body composition, BP variables, pulse rate, and cardiorespiratory fitness in overweight and obese adolescents. SIT, on the other hand, had limited effects beyond fat mass reduction.

Expert Review

Reviewer: Chloe Steele

9th Sep 2024

Conflict of interest

None

Take home message

The cardiovascular fitness and health outcomes may be improved in adolescents with overweight and obesity following a 12-minute HIIT programme twice a week for 8 weeks.
Adolescents who undergo a SIT exercise programme for 12 minutes twice a week for 8 weeks may find it has limited benefits to their cardiovascular fitness but may improve body composition.

Evidence category

A: Meta-analyses, position-stands, randomized-controlled trials (RCTs)

Summary review

Introduction

High intensity interval training (HIIT) has been shown to increase cardiovascular fitness, however its effectiveness on body composition and cardiometabolic risk factors remains unclear.
Effects may be due to the intensity at which the exercise is performed, duration of the exercise, and the rest interval.
This randomised control trial (RCT) aimed to determine the effects of both HIIT, and an exercise known as sprint interval training (SIT), which is performed at higher intensities for shorter durations, on body composition and cardiometabolic factors.

Methods

This was an RCT in 45 adolescents with either overweight or obesity.
Participants were split into SIT (n=15), HIIT (n=15), or control (n=15).
Body composition, blood pressure (BP), pulse rate (PR), and cardiorespiratory fitness were assessed.
Cardiorespiratory fitness was assessed using the Course-Navette test.
Enjoyment of exercise was also recorded.
Individuals in the SIT and HIIT group performed exercises twice a week for 8 weeks.
SIT exercises were less than 60 seconds in duration at maximum intensity and 6 sets were completed for a total of 12 minutes.
HIIT exercises were longer than 60 seconds at an intensity close to maximum and 3 sets were completed for a total of 12 minutes.

Results

Individuals in the SIT and HIIT groups showed improvements in fat mass (P=0.005 and P=0.003 respectively) and trunk fat mass (P=0.001 and p=0.005 respectively).
In addition only individuals in the HIIT group also showed improved lean mass (P=0.001) BP (P=0.013), systolic BP (P=0.044), diastolic BP (P=0.019), cholesterol:high density lipoprotein (HDL) ratio (P=0.003), low density lipoprotein (LDL) cholesterol (P=0.019), HDL (P=0.019), and cardiorespiratory fitness (P=0.002).
Improvements in BP and LDL were greater in the HIIT group compared to the SIT group (P=0.04 and P=<0.05 respectively).
No differences in enjoyment were seen following either SIT or HIIT exercises.

Conclusion

HIIT exercises improved more health-related outcomes than SIT exercises, although both did decrease fat mass.

Clinical practice applications

Exercise to improve body composition doesn’t need to be performed for extended periods of time.
If individuals only have a short amount of time to exercise, then to improve cardiovascular outcomes and cardiorespiratory fitness a high intensity workout needs to be performed at least twice a week for 8 weeks.

Considerations for future research

Further research could include an adult population to see how these two exercise regimes affect them.

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Abstract

OBJECTIVE

The aim of this study was to evaluate the effect of sprint interval training (SIT) and [high intensive interval training (HIIT)] carried out during the cool-down period of the physical education classes on body composition, blood pressure variables (BP) and pulse rate (PR), and cardiorespiratory fitness of adolescents who are overweight and obese, and to compare the differences in enjoyment in response to SIT vs. HIIT.

METHODS

For this randomized controlled trial, forty-five adolescents were recruited from a high school and were randomly placed into three groups. SIT and HIIT trained for 8 weeks, twice a week, for 12 min/session. Experimental group (EG) 3 was the control, and they maintained their regular physical education class schedule. The SIT group performed 6 sets of 60 s of work (90-95%HRmax) / 60 s of rest (50-55%HRmax), and the HIIT group performed 3 sets of 2 min of work (80-85%HRmax) / 2 min of rest (50-55%HRmax).

RESULTS

Both experimental groups showed a significant improvement in fat mass (FM) (%) and trunk FM (kg). In addition, EG2 reported a significance improvement in lean mass (kg), blood pressure BP (mmHG), systolic blood pressure (SBP) (mmHg), diastolic blood pressure (DBP) (mmHg), PR (bpm), and VOmax (ml/kg/min).

CONCLUSION

The present study found that a HIIT protocol performed during the cool-down period of the physical education classes generated adaptations such as improvement in body composition, BP variables and PR, and cardiorespiratory fitness, in overweight and obese adolescents. In contrast, the group of overweight and obese adolescents who performed SIT showed limited benefits, with changes in fat mass only.