Kids especially we have kids that are obese playing video games and eating chips. They need to get there lazy butts up and do something. 3 Hours is a lot but it has more pros then cons as it affects your health in a positive way. 3 Hours of exercise can change your life and make you feel more energized.
Biologically we are evolved for far more than 3 hours of exercise per day, the modern world simply places a different emphasis on being fat and lazy than does biology. If Finland can structure the educational day to sustain their current standards and create an effective exercise program for the children, there is nothing wrong with that.
Exercise is so good for kids. They need to be able to let out their energy, and it is important for their health. I think the more exercise they can get, the better off they will be in the long run. I would want my kids to get at least three hours a day.
The human body requires a ton of exercise to maintain top performance, and although three hours per day may sound excessive to Americans, it's quite reasonable in context. Kids are eating constantly, and without an outlet for that energy, they will get fatter and fatter. When it comes to weight, it's easier to just keep it off in the first place, and that means lots of running around.
3 hours of excercise for children does not mean three hours in a gym doing zumba or lifting weights. It means time spent playing and having fun. It simply means three hours total of physical activity rather than time spent siting at a desk or watching tv like most kids do now.