We were told so often how important our year 12 exams were to the rest of our lives that for years after I would wake up in cold sweats from dreaming I had turned up to the exam hall without studying.

The worst thing I did for myself personally in year 12 was cut out sport to focus more time on study. The result was not great and I kind of burnt myself out mentally around the time of my trial exams. Once I reintroduced sport, I was much less stressed. This is just my own experience and obviously everyone is different. But as a parent now I am aware of ensuring our kids remain active throughout their schooling life.

So, it was interesting to learn recently that researchers had found measuring the levels of the stress hormone cortisol in the hair of senior school students had proven that short, high-intensity exercise significantly reduces stress and improves memory, overall well-being 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 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 NSW.

Lead author and sport scientist from the University of Newcastle's School of Education, Professor David Lubans, said the findings boosted an argument for compulsory fitness to be included in 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 well-being 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.

Professor Lubans said primarily they wanted to measure cardiorespiratory fitness in senior school students, but early on also recognised secondary outcomes of muscle improvement, increased motivation, memory and enhanced mental health.

The researchers incorporated hair follicle testing as a novel method to reinforce their initial insights.

"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 observed a marked effect on engagement and learning in her classes and improvements in student well-being from the program.

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," he said.

"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.

Send your health and fitness news to r.valentine@newcastleherald.com.au.

Renee Valentine is a journalist, qualified personal trainer and mother of three.