Less than one in 12 teenagers in the United States engage in enough physical activity at school to meet national standards, according to a study reported in the journal Pediatrics.

The U.S. Department of Health and Human Services recommends at least 60 minutes of daily physical activity for those ages 6 to 17. The study reported that teenagers exercise an average of 23 minutes a day while at school. This figure made up over half of the total 39.4 minutes that the average teenager exercised every day, which means most do not exercise much on their own.

“Classes, socializing, extracurriculars, and keeping up with their media, our kids’ lives are packed with things to do,” WTNH-TV News 8 in Connecticut reported. “But are they packed with activity?”

Jordan A. Carlson, one of the authors of the study, reported that teenagers are “getting a lot less activity at school than we thought. We were surprised that they only spent about 4.8 percent of their time at school actually physically active.”

In light of this research, teens should strive to supplement school activity with an individual exercise routine at home. The Centers for Disease Control and Prevention recommend daily moderate-intensity aerobics, such as brisk walking and stretching, as well as the following types of exercise at least three days a week.

• Vigorous-intensity aerobics: Cardio workouts that maintain an average of 140 heartbeats per minute. These include long-distance running, swimming and bicycling.
• Muscle-training: Exercises that involve movement of specific muscle groups such as weight lifting or calisthenics.
• Bone-strengthening: Any exercise in which you move against gravity while staying upright to help maintain bone density. This includes dancing, hiking, stair climbing, tennis and jogging.

According to WebMD, following a daily exercise regimen provides better sleep, stronger immune function, a lower heart rate, quicker brain functions, stronger bones, better circulation, and greater confidence. It also improves skin complexion, prevents obesity, and reduces stress.

Fitness experts suggest that teenagers in particular should exercise with a safety-conscious friend. Using a buddy system can make workouts more enjoyable and safe, which makes teenagers more likely to maintain their routines.

Employing an exercise routine during adolescence can help ensure success for the future. Livestrong.com reported: “If teenagers can discover physical activities they enjoy, they are more likely to exercise on a regular basis and continue exercising into adulthood.”