A lot has changed in health research in 10 years, and the latest report shows just how much. On Nov. 12, the U.S. Department of Health and Human Services (HHS) released The Physical Activity Guidelines for Americans (PAGA), 2nd Edition. The report is an update of the 1st Edition of the Guidelines which was published in 2008. Dr. William Haskell, a researcher for The Cooper Institute and professor emeritus at Stanford University, served on the scientific advisory committee for the report and helped shape the new guidelines.
What counts as physical activity?
Physical activity is any bodily movement produced by skeletal muscles that requires energy expenditure. While many consider physical activity to be the same as exercise, the difference is that physical activity includes planned and structured exercise as well as unstructured activities like housework.
For example, a planned, structured exercise session might be walking two miles in 27 minutes at a heart rate between 120 and 135 beats per minute. An unstructured activity might be raking leaves or mopping the floor. Both are examples of physical activity, but only one is considered exercise.
As we all know, being physically active on a regular basis is one of the most important things that we can do to improve our health and prevent chronic disease. Unfortunately, it is one of the most ignored as approximately 80% of adolescents and adults do perform even the minimum requirements for physical activity.
What Has Changed:
Every minute counts. The 1st Edition stated that aerobic exercise had to be performed in bouts of at least 10 minutes in order to count toward the minimum recommendation of 150 minutes per week. The most current evidence clearly shows that the total volume of physical activity is what’s important for health benefits. This is good news because it means that if you walk up a few flights of stairs in one minute, or take a three-minute walk at work, this now counts towards your 150-300 minutes per week. In other words, the 10-minute requirement no longer exists.
Reap immediate benefits. We now know that a single bout of moderate to vigorous physical activity can improve sleep, reduce anxiety, improve brain function and sleep, reduce blood pressure, and improve insulin function on the day that the activity is performed. That means that taking a short walk can show immediate improvements in your mood, stress levels, blood pressure, and more.
Improved health in younger children. Evidence now shows that physical activity can result in improved bone health and weight status for children three to five years old and improved cognitive function for youth six to 13 years old.
Reduced cancer risk. In addition to a reduced risk of colon and breast cancer, there is now evidence that PA reduces the risk of cancer at additional sites.
Focus on brain health. We now have convincing evidence that regular physical activity improves brain health. More specifically, physical activity improves the quality of life mostly through reduced risk of anxiety and depression and improved sleep.
Fewer falls for elderly. Evidence now exists to show that physical activity results in a reduced risk of fall-related injuries for older adults.
Easier pregnancies. For pregnant women, there is now evidence that physical activity results in a reduced risk of excessive weight gain, gestational diabetes, and postpartum depression. During pregnancy and the post-partum period, women should perform at least 150 minutes per week of moderate-intensity aerobic activity each week.
Reduced mortality. For individuals with chronic medical conditions, physical activity results in a reduced risk of all-cause and disease-specific mortality (death), as well as improved quality of life.
Dangers of sitting. There is now a much stronger focus on reducing sedentary behaviors such as prolonged sitting. While there is no specific guideline in this regard, individuals are urged to break up sitting duration during the day. For example, you might choose to stand instead of sit during phone calls while at work and take short walking breaks throughout the day instead of sitting for long periods of time.
What Hasn’t Changed:
Children and adolescents ages six through 17 should perform 60 minutes or more of moderate-to-vigorous physical activity daily. Adults should strive for 150-300 minutes per week of moderate intensity or 75-150 minutes per week of vigorous-intensity aerobic physical activity. Additionally, adults should perform muscle-strengthening activities two or more days per week. Older adults should also include balance training to decrease the risk of falls.
The talk test is the most practical way to determine the level of aerobic activity. When performing moderate-intensity aerobic activity, you should be able to talk, but not sing. When performing vigorous-intensity activity, you will generally not be able to say more than a few words at a time without pausing to take a breath. If your ability to carry on a conversation or sing is not affected, then your intensity levels are not high enough to count towards your weekly goal of 150-300 minutes.
The scientific evidence for the health benefits of physical activity has significantly increased since the 1st Edition of the guidelines was published in 2008. Health and fitness professionals should make a strong effort to make their patients/clients aware of the many health benefits of physical activity, and provide guidance in this critical area.
Piercy, K.L., Trojano, R.P., Ballard, R.M., Carlson, S.A., Fulton, J.E., Galuska, D.A….Olson, R.D. (2018).
The Physical Activity Guidelines for Americans. JAMA. doi:10.1001/jama.2018.14854 Published online November 12, 2018.