Question: I've heard that being physically active can make my tween less depressed and anxious. She's been doing some walking for the past couple of weeks, but doesn't seem to be showing any improvements in mental health. How much physical activity is needed to make a difference?
Answer: The exact amount of physical activity needed to decrease symptoms of depression and anxiety in tweens remains unclear. Adults appear to experience mental health benefits when they engage in physical activity for just 30 to 60 minutes three to five times a week. Some researchers note that even less physical activity can help adults' depression and anxiety.
Tweens, however, should be getting more physical activity than adults, according to the U.S. Department of Health & Human Services. In particular, it's recommended that tweens be physically active for at least one hour every day. This activity should be of at least “moderate” intensity at all times, and of “vigorous” intensity at least three days a week. This means your daughter's heart should be pounding and her breathing should be rapid whenever she is exercising.
Does a tween need to engage in the fully recommended amount of physical activity in order to reap the psychological benefits? The jury is still out. The more physical activity, probably the better. But if your tween can make room for only a half hour of activity a day, that's a start, and her mental health may improve. Keep in mind that physical activity can take place in small chunks - such as 10 minutes at a time, multiple times a day - and still produce benefits. In addition, note that many things that your tween may be doing anyway, such as when hiking with friends or doing chores around the house, also count as physical activity.
All in all, support your child's efforts, whatever they may be, and accept that her psychological improvements may be gradual and/or minimal. Some moodiness in tweens is normal, anyway, and won't be budged by any amount of exercise. If your child's depression and anxiety become distressing, impairing or more severe, however, contact your child's doctor.
Sources:
U.S. Department of Health and Human Services. "Physical Activity Guidelines for Americans: Active Children and Adolescents." Accessed May 23, 2010 http://www.health.gov/paguidelines/guidelines/chapter3.aspx
U.S. Department of Health and Human Services. "Physical Activity has Many Health Benefits." Accessed May 23, 2010: http://www.health.gov/paguidelines/guidelines/chapter2.aspx