By the time our ancestors saw the end of the Pleistocene era, about 11,700 years ago, they'd embraced what some researchers call the Paleo Rhythm of life, which combined intense bouts of activity lasting a few days, followed by a more restful couple of days in which it would be usual to walk six or more miles to socialize.

That Paleo Rhythm comes close to the current recommendations for physical activity that combine strength training and aerobics, and banishing of sedentary habits.

If you want to get some Paleo Rhythm in your life, check out the new Physical Activity Guidelines for Americans put out by the Office of Disease Prevention and Health Promotion.

For the first time, they offer guidance for children ages 3 to 5. And they use scientific discoveries made since the first guidelines were established 10 years ago to make it clear that exercise not only improves heart health and longevity, it also benefits the brain, helps defend you from cancers, prevents falls, improves sleep and mood, and helps improve quality of life for people with chronic health conditions or disabilities.

Here are the guidelines by age group:

• Preschool-age children (3-5) should be active all day long, and caregivers should encourage active play.

• Children and adolescents up to age 17 should do 60 minutes or more of moderate to vigorous physical activity daily, mostly aerobics, and make it vigorous at least three times a week. Muscle-strengthening exercises (resistance training and weightlifting) as well as bone-strengthening exercises (jumping jacks, running, brisk walking and weightlifting exercises) should be part of that 60 minutes at least three times a week.

• Adults should move more and sit less. Substantial benefits come from a minimum of 150 to 300 minutes a week of moderate-intensity aerobics, or 75 to 150 minutes a week of vigorous-intensity aerobics, or a combo. Also do muscle-strengthening activities (resistance training and weightlifting) using all major muscle groups two or more days a week.

• Older adults should aim for the above, plus add balance-training activities like tai chiIf you cannot do that because of chronic conditions, be as physically active as you can.

Whatever your age or physical condition, getting into Paleo Rhythm will lower risk of cardiovascular disease, Type 2 diabetes, unhealthy blood lipid levels, some cancers, and all-cause mortality

So have fun and get moving like a caveman.