I’m starting a new project in which we will develop a ‘healthy digital playground‘ to stimulate physical activity in children. Stimulating physical activity sounded so benign, I didn’t even question the idea. But what’s the evidence that physical activity is healthy? And what counts as physical activity, is a nice and quiet activity like drawing enough? In this blog I’ll discuss a 2010 review on the health benefits of different levels of physical activity in children.
To start with the basics, the level of physical activity is defined by the energy you consume during an activity, and sitting counts as zero activity.
Moderate activity for the heart and metabolism
Most studies on physical activity have looked at moderate physical activity. A moderate physical activity is an activity where you burn 3 to 6 times more calories than you’d do seated. For instance cycling to school, a game of beach ball or roller skating. Moderate physical activity is healthy for the muscles, the heart and metabolic health. It prevents obesity and there are indications that it can prevent insulin resistance. Moderate activity is also important for the heart and veins: it is associated with low cholesterol and reduces high blood pressure. Finally, physical activity reduces depression.
Vigorous activity for stronger bones
Vigorous activity is an activity where you burn more than 6 times the number of calories that you would burn seated. To get an idea of the line between moderate and vigorous: a double’s game of tennis counts as a moderate activity whereas single’s game -involving more running- counts as a vigorous activity. Other examples are a game of soccer or trampoline jumping.
Overall, the science suggests that health benefits increase with the level of physical activity. Therefore adding a bit of vigorous activity would be better than only performing moderate activities. Moreover vigorous activity that creates impact forces on the bones is important for bone health. So jump for stronger bones!
Light physical activity
My mother sometimes marvels on how quietly I played as a child, drawing and making up fantasy worlds. The physical activities I engaged in most often were probably light physical activities. Activities in which you burn less than 3 times the amount of calories you’d burn seated. Examples of light physical activity are playing the piano, drawing, and walking slowly. Light physical activity hasn’t been enough to find measurable health benefits.
However, fans of quiet playtime do not have to worry: light physical activity is part of a healthy activity diet. The guideline for moderate to vigorous activity is to reach at least a total of 60 minutes a day. Whether it matters how you dispense these 60 minutes is unknown.