During routine clinical visits, physicians should determine patients' aerobic fitness, which may be an even better indicator of their risk for heart disease and premature death than smoking and hypertension, according to a scientific statement published in November 2016 by the American Heart Association.
Studies consistently show that the least fit patients see the biggest longevity benefits associated with relative increases in physical activity, according to the statement. “This has implications for physical activity counseling, given that considerable benefits are likely to occur by encouraging the most sedentary or low-fit people to engage in modest activity levels,” the authors wrote.
But patients, especially those with obesity, often do not get the most helpful physical activity counseling from their physicians, said Wendy C. King, PhD, associate professor of epidemiology at the University of Pittsburgh Graduate School of Public Health. “They may have been told by a doctor for years, ‘You just need to go out and exercise,’ and that alone isn't enough information or help,” she said.
When counseling patients, clinicians should be aware that physical activity and exercise guidelines differ along the weight management spectrum, said Dr. King. She offered tips on how to integrate evidence-based guidelines into clinical practice during her talk in November 2016 at ObesityWeek in New Orleans.
The basic parameters
Exercise and physical activity carry different meanings. Exercise is structured or planned physical activity that's done for the purpose of fitness or other health outcomes, whereas physical activity encompasses all bodily movement that increases energy expenditure, from recreation to housework, Dr. King said.
In terms of the duration of physical activity, a threshold of 10 minutes per bout is often used to categorize activity counting toward health outcomes, she said. Depending on the patient's current activity levels, frequency can be expressed as bouts per day or bouts per week, Dr. King said.
She noted several keys to physical activity counseling, such as setting short-term goals that are realistic, attainable, and measurable and gradually increasing the amount and intensity of physical activity over time. “It's OK to talk about 30 minutes per day at the beginning, but you wouldn't assign someone to start at 30 minutes a day,” she said. “You might assign them to 10 minutes a day and increase by 5 minutes every couple weeks.”
To encourage adherence, clinicians can help patients determine the appropriate activities for them by considering such individual factors as range of motion, agility, balance, coordination, and flexibility, Dr. King said. “You can't tell everybody to walk. Walking is a really great, cheap way to get your exercise. It doesn't work for everybody,” she said, noting that some patients may need to start off with chair- or water-based activity.
Keep in mind that the same activity can be done at many different intensities, so simply talking about a particular activity with the patient may not be enough guidance, Dr. King noted. “If it's too intense, they'll get discouraged or injured; if it's not intense enough, they'll have reduced benefits,” she said.
The energy cost of an activity is often measured in metabolic equivalents (METs). Sedentary behavior is defined as any waking activity, usually sitting or reclining, costing 1.5 METs or less (e.g., TV viewing, computer use), Dr. King said. Moderate activity is about three times that amount, and vigorous activity is about six times that amount, she said.
In general, research on activity intensity either assesses exercise or moderate- or vigorous-intensity physical activity (MVPA), a combination that exists partly because most patients don't do much vigorous activity at all, Dr. King said. But health benefits are not specific to exercise or MVPA, she said. “You can get health benefits from any kind of activity, and the more you do the better. However, the evidence shows there are stronger associations with moderate- and vigorous-intensity activity, especially aerobic activity, and health outcomes,” Dr. King said.
In addition to encouraging patients to be more active, clinicians should urge them to reduce their sedentary time by incorporating light activities, such as doing light housework or slowly walking the dog, she said. “The message that some activity is better than none is really important for clinical care. … We try to shift some sedentary behaviors to low-intensity and low-intensity behaviors to moderate,” Dr. King said.
To attain and maintain increased physical activity levels, patients need consistent encouragement, she said. “You want to do it during all phases of care and tailor standard recommendations to the unique issues of the patient,” she said. “And also, don't be afraid to provide referrals when needed for exercise testing, physical therapy, or exercise specialists.”
Even the most dedicated patients need ongoing support, Dr. King said. In randomized controlled trials, motivated patients can increase their activity level to improve weight and reap other health benefits if they have some clear guidance and persistent contact, she said. “That can be counseling or it can be supervised exercise, but … it's not sitting down with them once and expecting them to change their lifestyle,” Dr. King said.
Applying clinical guidelines
For adults to see substantial health benefits, the U.S. Department of Health and Human Services (HHS) recommends at least 150 minutes of aerobic moderate-intensity activity per week, in bouts of at least 10 minutes, according to the 2008 Physical Activity Guidelines for Americans, which are scheduled to be updated in 2018.
Dr. King said 150 minutes is not some magic number. “Often, you need to give people a number for a goal, but some is better than none, and more is better than 150 minutes,” she said. For even greater health benefits, the guidelines recommend two days per week of muscle-strengthening activities.
The National Heart, Lung, and Blood Institute's (NHLBI) clinical guidelines for managing adults with overweight and obesity differ from HHS’ general guidelines, Dr. King noted. “The 2013 obesity expert panel … went with 150 minutes per week during weight loss, but they recognize that you may need 200 to 300 minutes per week to maintain weight loss and minimize weight regain,” she said.
Increasing MVPA modestly improves weight loss during behavioral interventions in adults with overweight or obesity, Dr. King noted. “There have been systematic reviews showing that it has an additive effect, but really, in a six-month behavioral intervention, having a strong physical activity component may only result in additional 2% or 3% of weight loss,” she said.
A patient's diet typically plays a much bigger role in weight loss than activity, which plays a more important part during the weight maintenance phase, Dr. King said, adding that participants in the National Weight Control Registry, who've lost at least 30 pounds and kept it off for at least a year, rack up an average of 41.5 minutes per day of MVPA.
To prevent weight regain, Dr. King noted that recommendations from other professional societies are even higher than the NHLBI's, suggesting that adults with overweight or obesity get at least 250 minutes of moderate-intensity exercise per week (American College of Sports Medicine), 60 minutes per day (Institute of Medicine), or 60 to 90 minutes per day (International Association for the Study of Obesity).
Physical activity levels can also independently predict less weight regain among previously obese adults, Dr. King said. For instance, in trials with a six-month intervention followed by 18 months of no intervention, those with higher activity levels don't regain as much weight, she noted. In addition, exercise preserves fat-free mass, thereby increasing resting energy expenditure, Dr. King said.
Strength training during weight loss also attenuates muscle atrophy in those with obesity, she noted. “If you have a liquid diet or bariatric surgery or something where people are losing a lot of weight in particular, this is a concern,” Dr. King said. She noted that more research is needed to understand how varying the type, intensity, duration, and frequency of activity affects outcomes of bariatric surgery.
When counseling patients about their weight, clinicians should not forget to point out that the health benefits of physical activity go far beyond risk reduction, she suggested. “I think it's really important to bring up all these additional benefits of physical activity, including things like psychological well-being, cognitive function, and sleep quality,” Dr. King said.
Despite the myriad benefits of activity, getting patients to move more is very difficult in many cases, Dr. King said. “In general, Americans are too sedentary and they don't participate in enough MVPA, and that's because there's many barriers to meeting the physical activity guidelines,” she said, noting such challenges as lack of time, safety issues, and dislike of exercise.
For adults with obesity and those seeking bariatric surgery, additional barriers to activity may include lack of confidence, extreme fatigue, impaired mobility, or activity-induced pain, Dr. King said. They may also fear harming themselves. “That can be a real big one for some people,” she said. “They're afraid to get their heart rate up. They feel their chest pounding, and they think they're going to have a heart attack.”
Potential solutions for those who lack the confidence to go to a fitness facility or group exercise class include signing up for a gym orientation, working one-on-one with a fitness specialist, selecting activities that do not require equipment, determining alternative locations to exercise, trying to find classes aimed at beginners or older adults, showing up early to classes to speak with the instructor, and making modifications to exercises as needed, Dr. King suggested.
Ideally, every medical practice would have a fitness specialist to work with patients, she noted, but this is often not practical because insurance does not cover physical activity counseling. “So in that case, you can think about all health professionals promoting activity. … If you have an integrated team, it would be good to identify one person to lead the effort and then everybody else to echo those sentiments,” she said.