Prescribing exercise to help your patients lose weight

EXERCISE RECOMMENDATIONS

Any exercise program should target 30 to 60 minutes of effort per day, most days of the week, ie, 150 to 300 minutes per week or more.³⁸ But beginners should start low and go slow to avoid dropout, musculoskeletal strain, and joint injury.

The American College of Sports Medicine (ACSM)^38,39 recommends combining aerobic and progressive resistance exercise as the core components of an exercise program. The aerobic component can include anaerobic high-intensity interval training (see discussion below). In addition, we recommend flexibility and balance exercises for obese patients.⁴⁰

Three brisk 10-minute walks a day are at least as effective as one continuous 30-minute walk

Combining aerobic and resistance exercises likely results in greater decreases in abdominal adiposity in the obese.⁴¹ In addition, the aerobic portion of a combined exercise regimen can improve functional capacity, and the resistance portion may prevent injury by strengthening the muscles, bones, and joint support systems.⁴² Adding exercises that promote flexibility and balance helps with range of motion and prevents injuries while exercising.⁴³ These exercises not only expend calories during the exercise itself, but also increase resting energy expenditure for the remainder of the day, as the effects of the raised metabolism persist for hours.⁴⁴

Aerobic exercise is the foundation

Aerobic exercises that involve large muscle groups, especially walking, should be the foundation of cardiopulmonary exercise for obese persons.⁴⁵ Many patients can tolerate weight-bearing exercises such as walking or bike riding, but for some, exercises with limited or no weight-bearing such as swimming or aqua-aerobics are better.⁴⁶

Tips for prescribing. Patients should exercise:

• On 5 or 6 days each week
• At low to moderate intensity (30%–60% of maximum oxygen consumption [Vo₂ max])
• For at least 150 minutes per week, with a long-term goal of 300 minutes per week
• By walking, riding a stationary bicycle, or swimming.^38,47

To mobilize and use free fatty acids as an energy source, lower-intensity longer-duration aerobic exercise is preferred.⁵ Thus, frequent, low-intensity or moderate-intensity training (30%–60% of Vo₂ max) of longer duration (at least 60 minutes) may be the best approach to losing body fat in obese persons.^5,48 Early on in the exercise program, keep the intensity low, as high-intensity training will preferentially use stored glycogen or carbohydrate as an energy substrate rather than free fatty acids or fat.⁵

With light-moderate exercise, the heart rate will increase and patients will perspire, but they still should be able to carry on a conversation.

Measure (or have patients measure) the heart rate using the radial artery in their wrist after 6 minutes of walking. A pulse of 100 beats per minute or more is associated with an exercise intensity of approximately 50% (or more) of Vo₂ max.⁵

A study of 136 obese men and women who exercised for 6 months found that those doing aerobic exercise only and those doing a combination of aerobic and resistance exercise had greater cardiopulmonary fitness, greater reductions in abdominal and visceral fat, and more improved insulin sensitivity than those doing resistance exercise only.⁴¹ Although the aerobic­only group lost more weight (6 lb) than the aerobic-plus-resistance group (5.1 lb) and the resistance-only group (1.4 lb), combining aerobic and resistance exercise is considered optimal.

'SMART' goals: specific, measurable, attainable, realistic, timelyAll physical activity is beneficial, but activities that have less impact on the joints are less likely to cause injuries and joint pain. Aerobic activities that are especially useful in obese adults include walking at a speed of at least 2.5 miles per hour, bicycling, jogging, treadmill walking, swimming, aqua-aerobics, rowing, and low-impact aerobics classes.

Walking is the easiest way for most people to start their program, as it is safe, accessible, and relatively cheap with respect to equipment.³⁵ Adding a simple pedometer or smartphone app to measure the amount of exercise, together with physician counseling, may improve compliance and thus weight loss.^49,50

Obese patients may have been inactive for quite a while. Therefore, the sessions should be short and low-intensity at first, then steadily progress.⁵¹ To minimize dropout, avoid hard exercise too soon for people with a low exercise capacity or high body mass index at baseline, and give positive feedback and encouragement at each visit.⁵²

It is reasonable to introduce other aerobic exercises to vary the routine, use other muscle groups, and reduce the chance of injury from overuse of one muscle or joint group. Then, as cardiorespiratory fitness improves, the patient will be more confident about trying activities  that are more challenging, such as jogging and aerobics classes. An aerobic exercise program consisting only of swimming is less efficacious for weight loss in this population.⁵³

High-intensity interval training

High-intensity interval training involves relatively brief bursts of vigorous exercise separated by periods of recovery and is a time-efficient, novel alternative to continuous exercise.⁵⁴ The exercise component is anaerobic, meaning muscle movement that does not require oxygen. Anaerobic exercise uses fast-twitch muscle fibers, and thus helps that musculature to become stronger, larger, and more toned. Evidence suggests that high-intensity interval training induces health-enhancing adaptations similar to those of continuous exercise, despite a substantially lower time commitment.⁴¹

The ACSM recommends that most adults engage in moderate-intensity cardiorespiratory exercise training for at least 30 minutes a day on at least 5 days a week for a total of at least 150 minutes per week, or high-intensity cardiorespiratory exercise training for at least 20 minutes a day on at least 3 days a week for a goal of 75 minutes a week.³⁸ Thus, high-intensity interval training may be attractive for obese patients because it entails a shorter time commitment to achieve similar weight loss and improved insulin sensitivity than low-intensity or moderate-intensity continuous exercise.

High-intensity exercise has been shown to be effective for obese patients if they can do it.^54–56 In one study,⁵⁷ 134 obese patients, mean age 53, underwent supervised high-intensity interval training with resistance training two or three times a week, were encouraged to perform one or two additional exercise sessions a week (unsupervised), and were counseled to follow a Mediterranean diet. At 9 months, investigators noted a significant reduction in body mass, waist circumference, and fat mass.

Exercise targets: 30 to 60 minutes a day, most days of the weekA study of 12 weeks of high-intensity interval training, moderate-intensity interval training, or no exercise in 34 obese adolescent girls noted that body mass and percentage body fat were significantly decreased with both interval training regimens. However, the high-intensity group had greater reductions in waist circumference and more significant improvements in blood lipid levels, adiponectin levels, and insulin sensitivity.⁵⁸

Of 62 overweight and obese patients (mean age 53.3, mean body mass index 35.8 kg/m²), 97% adhered to a program of high-intensity interval training over 9 months, which resulted in an average weekly energy expenditure of 1,582 kcal.⁵⁵ Clinically and statistically significant improvements occurred in body mass (–5.3 kg), body mass index (–1.9 kg/m²), and waist circumference (–5.8 cm) (P < .0001 for all variables). Total fat mass, trunk fat mass, and lipid levels also significantly improved (P < .0001), and the prevalence of metabolic syndrome was reduced by 32.5% (P < .05).

In a meta-analysis of the effect of exercise on overweight adults, training of moderate or high intensity was noted to have the highest potential to reduce visceral adipose tissue in overweight men and women.¹³ Another meta-analysis noted that high-intensity interval training appeared to promote more improvement in fitness and similar improvements in some cardiometabolic risk factors than moderate exercise performed for at least 8 to 12 weeks in overweight patients.⁵⁶

A typical progressive exercise program for obese adults is shown in Table 1.

Progressive resistance exercise

Progressive resistance exercises are generally easier for obese patients, as they are not aerobically challenging, allow patients to exercise around physically active people who thus motivate them, and encourage positive feelings about completing their exercise sets.⁵⁹ The result is improved muscular fitness, socialization, and increased confidence in their abilities (self-efficacy).⁵⁹

Progressive resistance exercises also promote favorable energy balance and reduced visceral fat deposition through enhanced basal metabolism and activity levels while counteracting age- and disease-related muscle wasting.⁵⁹ They have been shown to improve cognitive ability, self-esteem, movement control, muscle mass, strength, glucose control, insulin sensitivity, resting blood pressure, lipid profile, and bone mineral density and to reduce fat weight, low back pain, arthritic discomfort, insomnia, anxiety, and depression.⁶⁰

Gym neophytes should spend a few sessions with a personal trainer to learn how to use the equipment.

While the primary goal of resistance training is more muscle strength, it can reduce fat and weight, burning up to 170 kcal in a 20-minute intense exercise session.⁶¹ It reduces both total body fat and visceral adipose tissue, thus benefiting obese persons by reducing insulin resistance.⁶² All exercise, and especially resistance exercise, can help to strengthen the musculoskeletal system, reduce muscle atrophy, and improve bone mineral density.⁶³

The ACSM guidelines³⁸ recommend progressive resistance exercise on 2 or 3 nonconsecutive days a week. It should involve:

• Exercises that work 8 to 10 muscle groups per session
• Two to four sets of 8 to 12 repetitions for each muscle group.

Exercising on nonconsecutive days allows time for the complete cycle of muscle tissue remodeling.⁶⁴ Such self-regulated intensity reduces the likelihood of excessive delayed-onset muscle soreness, which can discourage new participants.⁶⁵

To prevent muscle injury, obese people should begin with low-intensity workouts using lower resistance, one set of 8 to 12 repetitions 2 days a week. Then, they should gradually but progressively increase the intensity, volume, and frequency of the training.⁴⁷ This will obviate a plateau in training and will maximize musculoskeletal adaptation. The prescription should include exercises for the upper body (eg, biceps curls), lower body (eg, leg presses), and the midsection (eg, abdominal curl-ups, which give better abdominal muscle engagement and less risk to the back than crunches) and focus on the correct exercise form and function rather than the amount of resistance or weight lifted.

A typical progressive resistance exercise program for obese adults is shown in Table 2.

Flexibility exercise

Flexibility exercise involves stretching to improve the movement of muscles, joints, and ligaments.⁴⁵ While not specifically used in an energy-expenditure strategy, flexibility (or mobility) exercises help to increase or maintain joint range of motion and can reduce muscle and joint pain associated with obesity and exercise.⁶⁶

The ACSM recommends that stretching exercises be done when the muscles are warm after a brief warm-up or exercise session.³⁸ Typically, muscles should be stretched for at least 15 seconds, and stretching is recommended at a frequency of 2 to 4 days per week.³⁸

A good way to incorporate flexibility exercise is to join a yoga class, as yoga has been shown to improve strength and flexibility and may help control physiologic variables such as blood pressure, lipids, respiration, heart rate, and metabolic rate to improve overall exercise capacity in obese patients.⁶⁷

Balance exercise

Balance exercises help obese patients improve their stability. Poor balance is associated with injuries, accidents, and falls during activities of daily living.⁶⁸

Balance, the ability to maintain the body’s center of gravity within its base of support, can be categorized as static (sustaining the body in static equilibrium or within its base of support) or dynamic (maintaining equilibrium during a transition from a dynamic to a static state), which is more challenging.⁶⁹ Doing both static and dynamic balance training maximizes balance and stability.⁶⁹ While most activities that involve moving the body or body parts (such as walking) will improve balance, some additional balance exercises can be beneficial.

Balance exercises can be done without any equipment. Examples are balancing on one foot for 15 seconds and standing up and sitting down without using the hands. However, specific equipment can help, including physioballs, stability balls, cut-in-half stability balls, balance discs, balance wedges, wobble boards, rocker boards, and Indo boards.⁷⁰ In fact, balance boards and stability balls engage more muscle fibers in other areas of the body (lower back, lower abs, quads, hamstrings, and calves) than exercises done without those balancing devices.⁷¹

Balance training for at least 10 minutes a day, 3 days a week, for 4 weeks that incorporates various methods of balance training appears to improve balance.⁵⁶ Obese patients commencing a program should start with static balance exercises and then progress to dynamic ones. In addition, as balance training progresses, obese patients can integrate balance and stability training exercises with other pieces of equipment, such as performing squats on a balance board, and then gradually add weights (eg, dumbbells) to the exercise.

An example of a weekly comprehensive exercise program for an obese patient that incorporates all major exercise types is provided  in Table 3. In addition, some smartphone apps that are especially helpful in overweight newcomers to exercise include Couch-to-5K, GymGoal 2, Moves, Fitbit, Workout Trainer, Endomondo, MapMyFitness, Fitocracy, and Fitness Buddy.

BARIATRIC SURGERY AND LIFESTYLE MANAGEMENT FOR OBESITY

Bariatric surgery is a safe and effective treatment for severe obesity and comorbidities including type 2 diabetes mellitus, but weight loss and health outcomes vary considerably among individuals.^72,73 Of importance, postoperative weight loss after bariatric surgery and long-term weight loss largely depend on the extent to which patients can make and sustain changes to their lifestyle, including diet, exercise, and behavior modification.^72,74

Exercise, especially supervised, is associated with more weight loss after bariatric surgery.⁶¹ In a meta-analysis of bariatric patients, exercise participants involved in moderate or greater levels of exercise lost a mean of 3.6 kg more than the minimal exercise groups.⁷⁵ Another meta-analysis noted the beneficial effects of exercise incorporating more than 30 minutes a day of moderate physical activity following bariatric surgery and was associated with a greater weight loss of over 4% of body mass index.⁷⁶ These findings were consistent with those of yet another meta-analysis.⁷⁷

In summary, exercise appears to significantly increase weight loss after bariatric surgery.

TREATMENT CONSIDERATIONS IN MORBID OBESITY

Challenges faced by severely obese or morbidly obese patients affect their exercise options. The types of exercise they are able to perform are limited in most cases to very-low-impact, low-intensity exercises, which may not be as efficient in weight loss or weight maintenance.⁴⁸ Therefore, it may be prudent to set more conservative weight-loss goals for them, especially early in the program. Compliance and success rates may be better with low-impact activities such as walking, water aerobics, stationary cycling, and resistance training in the severely obese population.

The more severe the obesity, the more comorbidities such as diabetes, hypertension, hyperlipidemia, arthritis, sleep apnea, gastroesophageal reflux disease, and the greater the risk of metabolic syndrome—and conversely, the greater the potential benefit from bariatric surgery followed by exercise.⁷⁴

A LONG-TERM ENDEAVOR

For obese patients, a comprehensive exercise program will improve functional status, favorably influence cardiovascular risk factors, and help with weight loss or weight maintenance.

Managing obesity is a long-term endeavor.⁷⁸ For it to succeed, both the patient and the physician need to keep up their efforts. To keep the patient from becoming discouraged, the clinician should focus not just on weight, but also on improvements in metabolic profile and cardiorespiratory fitness. In addition, a careful evaluation, a clear exercise prescription, defined goals, ongoing monitoring (by the patient and the provider), frequent feedback, and charting of progress will improve daily performance and the chance of long-term success.