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Inside the Latest Physical Activity Guidelines
Len Kravitz, PhD

Fitness pros throughout the world extol the benefits of regular exercise to clients, educating them why starting and staying with an exercise program is the right journey for life. In November, 2018, the U.S. Department of Health and Human Services released the first update of their original 2008 physical activity report with the Physical Activity Guidelines Advisory Committee Scientific Report. Over a period of 20 months, a 17-member expert committee and consultants conducted an extensive scientific review of research, focusing particularly on articles published in the 10 years since the publication of the 2008 report. Overarching messages and details are presented in this column.

Current State of Physical Activity: We are Still an Inactive Society
The minimal physical activity recommendations for physical activity encourage adults to get at least 150 (and up to 300) minutes of moderate-to-vigorous aerobic activity each week, with muscle strengthening activities on two days during the week to stay healthy. Youth, ages 6 through 17 should do 60 minutes of moderate-to-vigorous physical activity each day. However, according to a press release from the U.S. Department of Health and Human Services, only 19 percent of women, 26 percent of men and 20 percent of adolescents meet these recommendations. According to the new report, the consequences of physical inactivity currently result in approximately $117 billion dollars in annual healthcare costs, with 10 percent of all premature mortality due to a physically inactive lifestyle. The evidence suggests that more time spent in sedentary behavior is associated with the incidence of type 2 diabetes, all-cause mortality, CVD mortality, and the incidence of colon, endometrial, and lung cancer.

Highlighted Findings from the New Physical Activity Guidelines Report
There are several key findings from the new report that warrant the attention to fitness pros, who may wish to share with clients.
Exercise is a boost in brain health: With every single exercise bout a person does, acute improvements in executive function occur. Executive function involves the processes of the brain that help a person manage their daily activities and plan for upcoming future events. Other aspects of executive function include handling behaviors, starting new tasks and controlling emotions. Physical activity has been shown to be a boost for also improving cognition (the process of acquiring knowledge), memory, attention and academic performance.

Exercise helps people manage depression: Consistent physical activity reduces depressive symptoms (or the severity of symptoms), and has been shown to be effective in reducing the risk of clinical depression. In addition, women doing moderate-to-vigorous physical activity are less likely to develop postpartum depression than their less active counterparts. As well, pregnant women with anxiety or depression can promote a healthy pregnancy, for both mother and fetus, even if they do low doses of physical activity.

Exercise helps improve the quality of sleep: There is impressive evidence that regular moderate-to-vigorous physical activity improves a person's quality of sleep. The research indicates that exercise lessens the length of time it takes to go to sleep as well as cuts the time a person is awake after going to sleep. Consistent exercise has also been shown to increase deep sleep while lowering daytime sleepiness. Most interestingly, the research also highlights that, in general, the time frame before bed time at which the physical activity is completed does not matter. The health benefits of exercise are equivalent for bouts of physical activity performed more than 8 hours before bedtime, 3 to 8 hours before, and less than 3 hours before bedtime.

Every bout of exercise, no matter how long, improves quality of life: A most encouraging finding in the new report is there are immediate health benefit from a single bout of activity, such as reduced anxiety improved blood pressure, better quality of sleep, and improved insulin sensitivity. In the 2008 guidelines it stated that a minimum of 10-minute bouts of physical activity was necessary to improve markers of health. This previous requirement has been removed, because activity, of any length of time, generates a positive impact on a person's quality of life.

Exercise is important for weight management: A stinging point for many fitness pros has been how various media and professional outlets have minimized the important role of exercise in weight management program. The report summarizes that there is a strong correlation between greater amounts of physical activity and decreased weight gain in adults. The evidence indicates a positive influence on exercise in weight gain prevention occurs when doses are greater than or equal to150 minutes per week at a moderate-to-vigorous level of intensity.

Walking step counts still make a difference. The new document states that step counts are quite easy to understood by most people and support the public health message to move more in a person's daily life. Walking steps can be at light-, moderate-, and vigorous-intensity levels, providing a broad range of exertion choice to promote walking for levels of fitness and at all ages. However, because of this range of intensities, and the potential for varied outcomes, the new physical activity guides does not support a specific number, such as 10,000 steps per day.

Higher intensity exercise is better for cardiovascular health. The new Physical Activity Guidelines clarifies that exercising at higher intensity brings greater gains in cardiorespiratory fitness than steady state exercise, but also has a greater risk of injury, especially if one is unaccustomed to vigorous physical activity. The report adds the caveat that the long-term sustainability of HIIT training regimens is currently not fully known. Alas, even with these impressive benefits of higher intensity exercise, the 2018 report recommends frequency and duration of aerobic activity should be increased before intensity, reaching these guidelines first.

Spread out the exercise through the entire week. Persons who accumulate all or almost all of their weekly moderate-to-vigorous physical activity on 1 or 2 days per week do NOT experience reductions in all-cause and cardiovascular mortality equivalent to those persons who accumulate an equivalent total volume on 3 or more days per week. Aim to spread out the exercise frequency on 3 or more days of the week.

Children benefit from regular exercise too: For the first time, the new report indicates there is research now showing that even 3 to 5 year olds also benefit from consistent physical activity. Importantly, the evidence conveys that higher amounts of physical activity are correlated with a reduced risk of excessive increases in body weight and adiposity, improved cardiovascular risk factor status, fewer symptoms of depression, and favorable indicators of bone health in children ages 3 to 17 years. The type of physical activity associated with bone health is hopping, skipping, jumping, tumbling and other forms of high-impact, dynamic, short duration exercise. Children should aim to accrue up to 60 minutes per day of moderate-to-vigorous physical activity.

Exercise is a must as we grow older: With persons greater than 65 years of age, considerable evidence has emerged showing the benefits of various modes or combinations of physical activity (e.g., progressive resistance training, multicomponent exercise, dual-task training, tai chi, yoga, dance) for specific physical function outcomes (e.g., activities of daily living, gait speed, strength, and balance). The term “multicomponent” describes physical activity interventions that include more than one type of physical activity, with common types being aerobic, muscle-strengthening, and balance training. Dual-task interventions combine cognitive intervention (such as counting backward) with a physical activity intervention. A target range of 150 to 300 minutes per week of moderate relative intensity activities is an appropriate target for older adults. Also, older adults expend more energy than younger adults for the same task, such as walking, so progress at a relative intensity based on their fitness level.

Summary Message to Fitness Pros: Please Share with Clients
The 2018 Physical Activity Guidelines report highlights that regular moderate-to-vigorous physical activity may reduce the risk of type 2 diabetes, gestational diabetes, hypertension, heart disease, stroke, excessive weight gain, dementia, anxiety, depression, postpartum depression, and falls with injuries among the elderly. Additionally, breast, colon, endometrial, esophageal, kidney, stomach, and lung cancer are all less common among individuals who are or become more physically active. If quality of life and improved physical function is a person's goal, regular exercise is the only way to go. Keep moving..briskly!

Figure 1. Highlighted Messages from 2018 Physical Activity Guidelines Advisory Committee Scientific Report

Len Kravitz, PhD, CSCS, is the program coordinator of exercise science at the University of New Mexico, where he received the Outstanding Teacher of the Year and Presidential Award of Distinction. He just released his third book, HIIT Your Limit (Amazon).

2018 Physical Activity Guidelines Advisory Committee. 2018 Physical Activity Guidelines Advisory Committee Scientific Report. Washington, DC: U.S. Department of Health and Human Services, 2018.
HHS Press Release: HHS Releases Physical Activity Guidelines for Americans, 2nd edition
Retrieved: January 20, 2019