CHARLESTON, W.Va. -- One of the most-asked questions sent to my inbox is: How much exercise do I need to do each week to be healthy? Generally, fitness professionals recommend 60 minutes a day for children and 30 minutes a day for adults.

However, the U.S. Department of Health and Human Services has just released the Physical Activity Guidelines for Americans, a comprehensive set of defined recommendations for people of all ages and physical conditions to consider.

This is the first time the federal government has set physical-activity guidelines that represent basic requirements for a foundation for healthier living. Furthermore, certified fitness professionals will now use these guidelines to assist them in designing programs that meet these recommendations.

These minimum standard guidelines are sensitive to age and also to specific physical limitation. The most exciting aspect is the distinction the new guidelines have made concerning moderate and vigorous activity.

Children and adolescents (6 to 17): One hour or more of moderate or vigorous aerobic physical activity a day, including vigorous intensity physical activity at least three days a week. They also should do muscle-strengthening and bone-strengthening activity at least three days per week.

Adults (18 to 64): Adults gain substantial health benefits from 2 1/2 hours a week of moderate intensity aerobic physical activity, or 1 hour 15 minutes of vigorous physical activity. Aerobic activity should be performed in episodes of at least 10 minutes, preferably spread throughout the week. Additional health benefits are provided by increasing to five hours a week of moderate-intensity aerobic physical activity, or 2 1/2 hours a week of vigorous-intensity physical activity, or an equivalent combination of both. Adults should also do muscle-strengthening activities that involve all major muscle groups performed on two or more days per week.

Older adults (65 and older): Older adults should follow the guidelines for other adults when it is within their physical capacity. If a chronic condition prohibits them, they should be as physically active as their abilities and conditions allow. Older adults should do exercises that maintain or improve balance if they are at risk of falling. People without diagnosed chronic conditions (such as diabetes, heart disease or osteoarthritis) and who do not have symptoms (such as chest pain or pressure, dizziness or joint pain) do not need to consult with a health-care provider about physical activity.

Pregnant and postpartum women: Healthy women who are not already doing vigorous-intensity physical activity should get at least 2 1/2 hours of moderate-intensity aerobic activity a week. Preferably, this activity should be spread throughout the week. Women who regularly engage in vigorous-intensity aerobic activity or high amounts of activity can continue their activity provided that their condition remains unchanged and they talk to their health-care provider about their activity level throughout their pregnancy.

Adults with disabilities: Follow the adult guidelines. Those who are able should get at least 2 1/2 hours of moderate aerobic activity a week, or 1 hour 15 minutes of vigorous aerobic activity a week. If this is not possible, these people should be as physically active as their abilities allow.

Children and adolescents with disabilities: When possible, these children should meet the guidelines for children and adolescents - or as much activity as their condition allows. Work with the child's health-care provider to identify the types and amounts of physical activity appropriate for them.

People with chronic medical conditions: Adults with chronic conditions get important health benefits from regular physical activity. They should do so with the guidance of a health-care provider.

Countless studies have made us all aware of the health benefits derived from regular physical activity and strength training. Still, 60 percent of American adults are not regularly active, and 25 percent of the adult population is not active at all. Even those who do enthusiastically engage in exercise do not maintain regular participation.

This challenges fitness professionals to study exercise adherence: why people begin fitness programs and then why they give them up. Clearly, we need to develop programming that is within a person's current physical capability and is also enjoyable. This varies from person to person. How and why people adopt and maintain healthier habits is as important to study as the health effects of these habits.

To adhere to these refined exercise recommendations and to make an ongoing health commitment, you should fulfill the time requirements with activity that suits your personality, energy level and makes you want to come back for more. People who do this find it much easier to "stick with a program" and reap the wonderful benefits from a healthy lifestyle.

Cindy Boggs, fitness presenter, author and Activate America director, has been an ACE-certified coordinator/instructor since 1989. Send your questions about fitness, training or health to YMCA of Kanawha Valley, 100 YMCA Drive, Charleston, WV 25311, or e-mail cindys...@aol.com. Look for Cindy's fitness advice book, "CindySays ... You Can Find Health in Your Hectic World" on her Web site www.cindysays.com or contact the YMCA at 340-3527.