Some 19% of boys in their first year of secondary school do not meet the minimum fitness levels required for good health, and this jumps to 41% by the time they reach the age of 16, new research has shown.

According to the findings, 8% of 12-year-old girls also fail to meet the minimum fitness levels required for good health, and this increases to 34% by the age of 16.

The research from Dublin City University (DCU) and Irish Life Health is based on data from Irish Life Health's Schools Fitness Challenge last year. This challenge is the largest fitness study of its kind in Ireland, and the third largest of its kind in the world.

It aims to help secondary school students adopt a healthier lifestyle by becoming more physically active over a six-week period. This year will mark the seventh year the event has taken place in Ireland and since it began, over 172,000 young people have taken part.

Over 30,000 secondary school students took part in the challenge last year, during which time, first-year students recorded an average 8-10% improvement in their fitness levels. The biggest improvement was recorded in at-risk teenagers with low fitness levels.

Physical activity offers physical and mental health benefits, including helping to maintain a healthy weight, reducing the risk of chronic diseases such as heart disease, and improving general wellbeing.

"We really can't ignore the fact that more than a third of 16-year-olds in Ireland are now at risk of developing premature cardiovascular disease. The impact on their long-term health and our healthcare system is undeniable.

"The progressive decrease in fitness seen in boys and girls as they progress through post-primary school is alarming and should be a wakeup call for parents, teens and healthcare professionals," commented Prof Niall Moyna of DCU.

However, he emphasised that ‘substantial improvements' can occur after just six weeks of regular exercise, with low-fit teenagers benefitting the most.

"I would strongly encourage all students and particularly those who are not physically active or involved in organised sport to give it a go," he said.

Schools Fitness Challenge ambassador and physiotherapist, Louise Galvin, acknowledged that it can be intimidating to begin a new activity, especially for young people who do not consider themselves fit.

"However, it can be something as simple as a daily brisk walk, or cycling to school instead of hopping in the car. I find team sports are such a social way to connect with people, but if that isn't your thing, you could walk in the evenings with a friend, play tennis weekly or just find something that works for you. The long term health benefits, as well as the social, are fantastic," she insisted.

Registration for the challenge is now open to all secondary schools nationwide. PE teachers can register their school here. Registration ends on September 21, 2018.