As children become teens, they become less active.

Children are getting fatter by the decade, federal health numbers show. It’s no wonder, because one of the largest studies of its kind found that while 90 percent of 9-year-olds get a couple of hours of exercise most days, fewer than 3 percent of 15-year-olds do. In fact, the study found that less than a third of teens that age get even the minimum recommended by the government — an hour of moderate-to-vigorous exercise, like cycling, brisk walking, swimming or jogging. “What shocked me was the sharp decline in activity,” said Dr. Philip Nader, a former pediatrics professor at the University of California-San Diego, who conducted the comprehensive study, which followed more than 1,000 children for six years. “While we all knew children and youth were moving less, the magnitude of the rate of decline calls for renewed action to increase activity levels in the population,” Nader said. The study monitored the habits of the same children from different parts of the country, with different family incomes and different races. At 9 years old, the kids got on average about three hours of moderate to vigorous physical activity a day from activities like bike riding, tag or basketball. But, by the time they turned 15, their activity had dropped down to about 49 minutes a day. On the weekends, it was even worse – kids got about 35 minutes a day. Boys were more active than girls at every age. But by age 15, even boys’ average activity levels fell short of recommendations, particularly on weekends. The sharp drop raises concerns about inactivity continuing into adulthood, which could endanger kids’ health throughout their lives, the study authors said. “People don’t recognize this as the crisis that it is,” Nader said. Inactivity is linked with greater risks for many health problems, including heart disease, obesity, high blood pressure and diabetes. It is also seen as the major cause of the increase in childhood obesity, the researchers said. “Program and policy action are needed immediately at the family, community, school, health care and governmental levels to find ways to encourage children to remain active as they get older,” said co-author Renate Houts, Ph.D., research statistician and psychologist at RTI International. “Unless parents, elected officials, and volunteer and philanthropic organizations begin creating new opportunities for children’s activities, childhood obesity rates will likely continue to rise.” The findings are revealed in the Journal of the American Medical Association that comes out Wednesday. For simple ways to get teens moving, go to Vital Signs.
Global warming linked to rise in kidney stones
Rising temperatures and increased dehydration linked to global warming will boost kidney stone rates in the United States and around the world, new research suggests. In the United States in particular, hotter weather will lead to a dramatic rise in kidney stone disease among residents of southern states – the so-called “kidney-stone belt,” HealthDay.com reports. This will result in an increase of 1.6 million to 2.2 million additional kidney stone cases by 2050, according to the study. “This is an example of how global warming will affect people directly,” said study author Tom Brikowski, an associate professor with a specialty in hydrology in the department of geosciences at the University of Texas at Dallas. The study authors stressed that the exact degree of the increased risk remains unclear. But, Brikowski added, “We are certain that warming will increase, and that the rate of kidney stone disease will go up. So as a nation, we will have to pay more attention to this problem.” According to the U.S. National Kidney and Urologic Diseases Information Clearinghouse, about 5 percent of Americans develop kidney stones at some point, with the risk rising as men and women enter their 40s and 50s, respectively. Typically composed of calcium and other minerals found in urine, a kidney stone is a hard, crystallized mass that passes – often painfully – through the urinary tract. Drinking too little fluid and/or dehydration can lead to development of a stone, as can a metabolic predisposition for kidney stone disease, known as nephrolithiasis. Brikowski and his colleagues said the “kidney-stone belt” includes Alabama, Arkansas, Florida, Georgia, Louisiana, Mississippi, North Carolina, South Carolina and Tennessee. But with global warming, the risk of kidney stone disease could ultimately touch a much wider swath of states, stretching from Kentucky all the way to northern California, the researchers said. The findings are reported in this week’s issue of the Proceedings of the National Academy of Sciences.