Hair reveals short, intense exercise sessions conquer school stress

Apr 22 2021

For the first time, measuring the levels of the stress hormone Cortisol in the hair of senior school students has proven that short, high-intensity exercise significantly reduces stress and improves memory, overall wellbeing and fitness in adolescents.

With physical activity largely non-compulsory for Australian students in years 11 and 12, new research has revealed the long-term benefits of upskilling teachers to incorporate High-Intensity Interval Training (HIIT) sessions into their regular lesson planning.

Published in the prestigious British Journal of Sports Medicine, the randomised controlled trial targeted 670 senior students from a range of socio-economic backgrounds across 20 government schools in regional New South Wales.

Lead author and sport scientist, Professor David Lubans, said the findings bolstered the argument for the incorporation of compulsory fitness into the senior curriculum.

“We know that physical activity declines during adolescence and yet school-based interventions targeting adolescents have been largely unsuccessful,” Professor Lubans said.

“At a time when young Aussies are navigating stressful exams, managing relationships and all the additional pressures on them in the modern world, any extra support we can give them to enhance their mental health and wellbeing should be a priority.”

HIIT involves repeated short bouts of intense exercise (resulting in a heart rate above 85 per cent) followed by short periods of rest.

The study – Burn 2 Learn – involved two to three 10-minute HIIT sessions per week, led by a teacher trained in the program. Classes could choose from 10 different styles of workout – ranging from strength training; to dance; to martial arts.

To encourage social support amongst the cohort, sessions were completed together as a class however students were self-directed in their workout. A heartrate monitor was required during each session to log their data.

“The primary output we wanted to measure was cardiorespiratory fitness in senior school students, but very early on in our pilot we recognised secondary outcomes of muscle improvement, increased motivation, memory and enhanced mental health,” Professor Lubans said.

“From there, we decided to target subgroups comprised of students with poor mental health and students classified as above the recommended weight range.”

Bringing together a cross-disciplinary team, the researchers incorporated hair follicle testing as a novel method to reinforce their initial insights. Consenting students provided a hair sample before and at the end of the trial.

“We were excited to see a positive effect on hair cortisol concentrations, which means the changes to lifestyle actually reduced the amount of stress hormone being released,” Professor Lubans said.

“Better yet, we also found an improvement in memory and an ability to better cope with internalising problems in a subsample of students.”

Study participant and Deputy Principal, Michelle Maher, said she had seen huge improvements in student wellbeing.

“It can be really tricky to motivate high school students when they’re facing school and exam stresses. As with all of us, commitment to physical activity can slide when life gets busy, which is why we found it effective for a teacher to lead the sessions as part of their usual lesson planning,” Ms Maher said.

“We also can’t assume every child has equal access to a gym or organised sport outside of school, so the Burn 2 Learn program was a great way to ensure equitable access for all students.”

A former teacher himself, Professor Lubans said that physical literacy should be considered an important life tool.

With funding support from the NSW Department of Education and the National Health and Medical Research Council, Professor Lubans hopes to work with key decision makers to ensure the positive outcomes are implemented to benefit all students.

“I truly believe equipping young Australians with the skills to maintain lifelong health and fitness is just as important as subjects like English or Mathematics. With the proven positive impact, physical literacy will ultimately improve quality of life for Australians.”

The Burn 2 Learn study involved collaborators from the University of Newcastle, Hunter Medical Research Institute, Australian Catholic University, Northeastern University Boston, University of Wollongong, University of Southern Queensland and Deakin University.