Schools are being encouraged to get more kids walking and cycling for short journeys.
NICE, which offers health advice, is asking schools to work with pupils on developing travel plans that get children to walk or cycle all or part of the way to school.
Just over half of boys, and only a third of girls, aged two to 10 are getting enough exercise every day.
We asked you how much exercise do you do? Do you reckon you get enough?
Do you walk or cycle to school? Do you enjoy it or would you prefer getting the bus? Or maybe your parents take you in the car?
The chat is now closed but here's a selection of your comments below.
"I walk to school every morning whatever the weather. It makes me feel nice and fresh for when I get to school."
Hannah, Dublin Ireland
"I cycle to school every day. It's 4 miles away - so 8 miles every day. I definitely get enough exercise!"
Helen, Surrey, England
"I would like to cycle to school but it's too far so I have to go by car."
"I walk to school every day and once I walked in the snow! I think it was about -6 degrees so it was very cold but it helps the planet so I don't care!"
Nathan, Somerset, England
"I walk every day to school. All my friends get the bus but I prefer walking. I live 30-35 minutes from my school. It helps wake me up so I'm all ready for school"
Molly, London, England
"I usually take my bike to school. But when it's raining I take the car"
Charlotte, Bristol, England
"I walk to school because it helps keep me fit, stops pollution and it's really fun to walk with my friends."
Charlotte, London, England
"I walk to school in ALL types of weathers because it's good exercise and it saves the environment."
Sarah, Manchester, England
"I have to go on the bus because we live too far away - but I would prefer walking."
"I walk because I live quite close to my school and I meet friends on the way so my journey isn't boring"
Ayush, Buckinghamshire, England
"I like to walk to school because it's good exercise and it wakes me up in the morning. The birds are there every morning so it's like I'm getting a nature walk."
"Every day we walk to school even in the rain because we like helping the environment!"
Georgia and Iza, Hertfordshire, England
"I always walk to school, even though it is 1 mile there and 1 mile back! I like walking because you can talk to your friends for a longer time before school which starts your day well!"
Catherine, Cambridgeshire, England
"I would prefer to cycle rather than go by car but the problem is that I live too far away and I'm not allowed to go alone."
Katie, Worcestershire, England
"Since my school is 15 minutes away I walk or take a bus depending on the weather. Walking is BEST!"
Shahana, London, England
"I walk to school and so do my brother and sister. I think it gives you exercise and makes you healthier."
Phoenix, Dorset, England
"I don't do either - but I would seriously prefer to walk rather than catch a train to my secondary school, it's such a pain, you wait for ages, and once I got lost on my way to the train station and missed my train and was fifty minutes late."
Cambria, London, England
"I walk to school because I live around the corner from it and it's good fun."
Andrew, Aberdeen, Scotland
"I cycle to school because it makes me healthy."
Charolett, Hampshire, England
"I would like to walk to school but it is too far away so I have to get the bus."
Jessie, Watford, England