Americans are suffering from more lifestyle-related diseases than ever before. It is no wonder that the promotion of physical activity is at the forefront of health professionals’ minds. As a registered dietitian and health-minded individual, I, too, am well aware of the importance of balanced and regular physical activity to promote both physical and mental health. Most Americans lead lives that are largely sedentary. Across the lifespan, people could benefit from integrating more variety and consistency into their activity. At the same time, an increasing number are struggling with eating disorders or injuries attributed to overly vigorous exercise. How can we find a balance of activity that supports our long-term health? What is the state of physical activity in the US? Currently, it’s estimated that only 23 percent of adults and 22 percent of children and adolescents meet the national guidelines for activity (see below), with significant variability observed by gender, state and ethnicity. Men are more likely than women to meet the guidelines. Indicating some progress, the proportion of adults who meet the guidelines has increased a couple of percentage points over the past decade. But, a recent study by JA Bennie et al. showed that 58 percent don’t do any muscle-strengthening activity. And as of 2017, 28 percent of Americans were considered sedentary.
How does physical activity promote health? Everyone knows that burning calories and building muscle through physical activity help to maintain a healthy weight. But researchers continue to discover both the short- and long-term health benefits of various forms of physical activity, as well as the harms of excessive sitting. A 2017 observational study by Diaz et al. demonstrated that, regardless of activity level, prolonged and uninterrupted sedentary behavior increases risk for all-cause mortality—indicating the importance of breaking up sitting with even short bouts of movement. If followed in a safe and balanced manner, physical activity helps to manage chronic conditions, such as reducing pain among those with arthritis. It can improve cognition for those with dementia or reduce the progression of hypertension and type 2 diabetes (independent of weight loss). It can improve sleep and diminish anxiety, lessen the risk of cancer later in life, strengthen bones and lessen the likelihood of osteoporosis, and ultimately improve the quality of life. What are the physical activity guidelines for Americans? Experts at the US Department of Agriculture and US Health and Human Services jointly release Dietary Guidelines for Americans (DGAs) roughly every five years. They have also recently begun to publish Physical Activity Guidelines for Americans (PAGAs). The first edition was published by the Office of Disease Prevention and Health Promotion in HHS, with additional support from other federal staff. The second edition was published in late 2018 and includes recommendations unique to various life-stage groups. It also references additional health states, emerging evidence about the dangers of excessive sedentary behavior and evidence-based strategies for increasing activity.
Key guidelines include the following:
Adults should aim for at least 2.5 hours of moderate-intensity activity or 75 minutes of vigorous physical activity each week. They should also engage in muscle-strengthening activities at least two days per week.
Children and adolescents should aim for one hour of moderate-to-vigorous physical activity each day. Aerobic activity should be the primary form of exercise, augmented by muscle-strengthening and bone-strengthening activity three times per week.
Preschool-aged children should be active in a variety of ways throughout the day.
In addition to the general guidelines for adults, older adults should incorporate balance training.
Pregnant and postpartum women should also aim for 2.5 hours of moderate-intensity activity per week. Vigorous activity can continue if it was part of the expectant mother’s exercise routine before becoming pregnant.
Finally, adults with chronic health conditions or disabilities should aim for the same guidelines as healthy adults, but they should work with a healthcare provider to modify as necessary for any debilitating chronic conditions.
What types of physical activity should be included? Physical activities can be categorized as either moderate or vigorous intensity. Technically, these categories are defined by a metric known as metabolic equivalents (METs), with one MET equaling the energy required to sit still. Moderate activity ranges from three to six METs, with the heart rate rising to between 50 and 70 percent of your maximum heart rate (maximum heart rate is equal to 220 – age). Vigorous activity exceeds six METs and a heart rate of up to 85 percent of your maximum. Individuals should notice faster breathing and an accelerated heart rate with moderate activity, but they should still be able to talk. Vigorous activity leads to sweating within a few minutes and prevents a conversation of more than a few words. METs are considered a measure of absolute intensity and are scaled equivalently for everyone, while heart rate and breathing are measures of relative intensity, accounting for the fact that everyone’s fitness level differs.
Suitable examples of each for both children and adults may include:
What physical activity is right for me? High-end fitness studios that offer luxurious experiences may not be practical or accessible to everyone. A busy family and work schedule might also prevent you from joining regularly scheduled group classes.
Are there ways to integrate more physical activity into your daily routine? Even 10-minute bouts of exercise throughout the day can add up quickly to support good health, so adjusting a few behaviors can make it much easier to reach your activity goals. For example:
Take the stairs instead of the elevator if you work or live on the bottom floors of your building.
Wash your car instead of taking it to the carwash (bonus: include your children).
Walk to the grocery store that’s 10 minutes away when you need only a few items.
Opt for a 15-minute walk with a coworker when you need a mid-afternoon break (bonus: you might avoid buying that sugar-filled latte).
Park your car at the back end of the parking lot to fit in a bit of extra walking (bonus: you’re likely to avoid swinging car doors).
If you’re sitting to watch TV, take advantage of every commercial break to do a few yoga poses or crunches, or lift two light weights.
If you’ve been sitting for more than one hour straight, stand up for a quick stretch and, ideally, take a brief walk to the water fountain or restroom to move your legs.
The next time your friends are planning a night out, try salsa, line or ballroom dancing to fit in some exercise and fun.
Try using a fitness tracker to see just how active you are throughout the day and set attainable goals to increase your activity. While scientists questioned the effectiveness of earlier models, newer trackers may hold promise for encouraging more prolonged usage.
How can I improve my physical activity?
If you’re currently exercising less than the recommended 2.5 hours per week, aim to fit in at least two of the activities mentioned above each day and start with three or four 20-minute bouts of activity each week. You can then build your way up over time.
If you’re exercising more than five hours per week, ask yourself: Is your regimen inhibiting your social life or your sleep quality? Does your body feel fatigued? Are you constantly thinking about exercising and how to fit it into your schedule? Do you feel hungry so often it takes over your mental focus? If you answered yes to any of these questions, try talking with a personal trainer, registered dietitian or primary care physician about adopting a healthier exercise regimen that allows your body to rest and recover.
If you’re interested in weight loss, be sure to include a mix of both cardio and strength-training activities. Remember to replenish with water and electrolytes and include a mix of complex carbohydrates and protein following prolonged activity.
If you’re interested in trying a group class but want to start slowly, try taking one at home. Many websites and apps offer excellent and affordable (or free) classes adapted for your home or yard. A few favorites include Tone It Up, Grokker, Barre3, and NEOU.
Whenever possible, include friends or family in your activity plan. The accountability and additional opportunities for fun and conversation make you more likely to stick with your plan.
Resources
Bennie, JA, Lee, DC, Khan, A, Wiesner, GH, Bauman, AE, Stamatakis, E, and Biddle SJH. (2018). Muscle-Strengthening Exercise Among 397,423 U.S. Adults: Prevalence, Correlates, and Associations With Health Conditions. Am J Prev Med. 2018;55(6):864-874.
Blackwell, DL and Clarke, TC (2018). State variation in meeting the 2008 federal guidelines for both aerobic and muscle-strengthening activities through leisure-time physical activity among adults aged 18–64: United States 2010–2015. National Health Statistics Reports; no 112. Hyattsville, MD: National Center for Health Statistics.
Diaz, KM, Howard VJ, et al. Patterns of Sedentary Behavior and Mortality in U.S. Middle-Aged and Older Adults: A National Cohort Study. Ann Intern Med. 2017;167(7):465-475.
National Physical Activity Plan Alliance. 2016 US report card on physical activity for children and youth. Columbia, SC; 2016.
Office of Disease Prevention and Health Promotion (2018). “Physical Activity Guidelines for Americans, second edition.” US Department of Health and Human Services.
Office of Disease Prevention and Health Promotion (2018). “Executive Summary: Physical Activity Guidelines for Americans, second edition.” US Department of Health and Human Services.
Physical Activity Council (2018). “2018 Participation Report: The Physical Activity Council’s annual study tracking sports, fitness, and recreation participation in the US.”
Christina Badaracco, MPH, RD
Christina is a registered dietitian and author who aims to improve access to healthy and sustainable food and educate Americans about the connections between food and health. She loves to experiment with healthy recipes in the kitchen and share her creations to inspire others to cook. Christina completed her dietetic internship at Massachusetts General Hospital and earned her Master of Public Health degree from the University of California, Berkeley. Previously, she graduated with a degree in Ecology and Evolutionary Biology from Princeton University, after conducting her thesis on sustainable agriculture and energy in Kenya. She has done clinical nutrition research at the National Institutes of Health, menu planning and nutrition education at the Oakland Unified School District and communications at the Environmental Protection Agency’s Office of Water. She has also enjoyed contributing to children’s gardens, farmers’ markets and a number of organic farms. cbadarac@gmail.com www.linkedin.com/in/christina-badaracco/
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