Trying to prevent obesity and thus health problems related to obesity, the Department of Health and Human Services announced Tuesday its physical activity guide destined to all Americans, no matter age, race or pounds they carry.

The new “Physical Activity Guidelines for Americans,” as the guide was called, is the most comprehensive guide ever based on the first thorough review of scientific research about physical activity and health in more than a decade, the government said in a statement.

Americans are highly recommended two and half hours of physical activity a week as a way to prevent a range of health problems such as obesity, heart disease, type 2 diabetes, colon cancer, breast cancer, osteoporosis, Alzheimer's disease, depression, and the list could go on. Exercise is also known to prolong life if done regularly.

“The evidence is clear – regular physical activity over months and years produces long-term health benefits and reduces the risk of many disease,” US Health and Human Services Secretary Mike Leavitt said.

However, the actual recommendations vary depending on age and level of fitness. The more fit you are, the more exercise you need. On the other hand, the more you exercise the better your health condition is. “The more physically active you are, the more health benefits you gain,” Leavitt said.

As for those who find little time for physical activity or aren’t crazy in love for fitness, some ten minutes a day of speeding up on their way back from work or grocery store or playing with their kids in the back yard should be enough to maintain them in shape, but only if they do it on regular basis. “The easy message is get active, whatever your way is. Get active your way,” Leavitt added.

According to latest statistics of the Centers for Disease Control and Prevention, obesity is in continuous growing in the US, affecting more than one in four adults. While in 2005, 23.9 percent of US adults were obese or had a body mass index greater than 30, in 2007, the percentage had grown to 25.6 percent. This percentage translates in more than 60 million adults. Both poor diet and a lack of exercise are blamed.

When it comes to kids, the situation is even worse. About a third are overweight and 16 percent are obese, a situation that is getting out of control, as the calories in their favorite foods keep going through the roof and as schools are decreasing the amount of recess and gym time. According to a recent study, by the time they reach high school, fewer than a third of teens are getting an hour of activity a day. In their case, brisk activities for at least an hour a day are recommended, the guidelines concluded.

The guidelines are available on the Internet at www.health.gov/paguidelines.