Weight Loss Strategies: What Our Cardiac Rehabilitation Patients Need to Know

Glen Porter, PHD, EP and Carol Ghylin, BSN, RN, BC
John Muir Medical Center, Cardiac Rehabilitation

The purpose of this article is not to provide any new insight, but to highlight the concepts that our cardiac rehabilitation patients must understand in order to achieve successful short and long-term weight management. We will not focus on detailed nutrition or diet information, as any diet plan is only a means of controlling caloric intake. We will instead address the role of exercise and how it interacts with caloric intake to achieve effective weight management.

The Centers for Disease Control now considers obesity to be the number one health threat in the US, and the American Heart Association lists obesity as a major modifiable risk factor for coronary heart disease (CHD). It is no longer debatable that individuals who are obese are at increased risk of complications from hypertension, CVA, lipid disorders, type II diabetes, CHD, certain types of cancer as well as many other medical conditions.

There is no question that significant weight loss is a primary goal for a majority of Americans, and our cardiac rehabilitation patients are no exception. Low levels of physical activity, resulting in fewer calories utilized than are consumed contributes to the high prevalence of obesity in the US. With this being said, it is our opinion that weight loss should not be a major outcome measurement during the phase II program of cardiac rehabilitation, but instead a long-term goal for those with the documented obesity risk factor. Both the short and long-term goals will require time beyond the given phase II time frame. A phase II program should begin with education, instruction and development of strategies necessary to reach these goals. Upon completing phase II, the patient must have adequate knowledge and a firm grasp of the concepts related to nutrition and exercise for any weight loss program to be successful.

Many patients would be successful with weight loss if they practiced two simple concepts – eat less and exercise more. Just be more physically active each day. Quite simple in theory, but like many other modifications we ask our patients to undertake, a bit more difficult to pull off. Nevertheless, inactivity is only half of the energy balance equation. The total number of calories consumed count! The most successful strategies for weight loss include the following: calorie restriction, increased physical activity and behavior modification designed to improve eating and exercise habits.

Being fitter is likely more important than carrying some extra weight. Remember, the problem is the excess body fat and not necessarily the absolute body weight itself. By becoming fitter in most cases, body weight will tend to normalize and body fat will decrease. This happens because being fitter requires a considerable change in exercise habits with a concurrent change in nutritional habits.

The Body Mass Index (BMI) is often used to obtain a simple estimate of a person’s body composition and body weight classification. A BMI of 25-29.9 is considered overweight, and a BMI of 30 or > is considered obese. Therefore, those patients with a BMI >25 would benefit from appropriate weight (fat) loss. In addition, we feel that using a skinfold caliper to document changes in skinfold thickness is a very useful tool in the hands of an experienced tester. It is much easier for the patient to relate to a simple measurement being taken of a skinfold rather than a calculated number taken from a mathematical equation. A decrease in skinfold thickness indicates decreased body fatness.

Usually if an individual’s body weight has been stable for several weeks, it is safe to assume they are in caloric balance. Caloric balance refers to the relationship between caloric intake and caloric expenditure. Body weight is lost when caloric expenditure exceeds caloric intake and body weight is gained when caloric intake exceeds caloric expenditure. To lose body weight, this previous balance must be upset in a fashion where a negative caloric balance is created or where caloric expenditure exceeds caloric intake. Change in body weight is closely related to specific behaviors that lead to caloric imbalance. Starvation diets (diets <800 kcal/day) cause a loss of body weight by marked losses of water and fat-free (lean tissue) body mass. Exercise-induced caloric imbalance leads to a greater loss of body fat mass. Resistance training may help preserve fat-free body mass, and more fat-free mass generally increases the basal metabolic rate (BMR).¹ An increased BMR results in an additional caloric expenditure over a given day’s time. A combination of cardiovascular (aerobic) training and resistance training contributes to the loss of body weight and fat stores, thus maximizing the potential to maintain these changes over time.

It is important to understand that one pound of body fat is equivalent to approximately 3,500 kcal of energy.1 In order to lose one pound of body weight, a negative caloric balance of 3,500 calories must be created. The individual must acknowledge that this caloric deficit is nearly impossible to attain by exercise alone, and certainly not by doing a mere 10-15 minutes of physical activity per day. For most individuals, the optimal approach to weight loss combines a mild caloric restriction (300-500 kcal/day - not to exceed 1,000 kcal/day) along with regular endurance exercise. For example, add an exercise program that promotes daily caloric expenditure of 300-500 kcal/day and approximately 1,000-2,000 kcal/wk.¹ For most individuals, this is best accomplished with moderate intensity, long-duration exercise such as walking. The number of calories expended is a product of exercise intensity and duration. An individual who is fit may be able to exercise at a vigorous level for a shorter duration. The emphasis must be on the total calories expended. An initial goal might be to reduce body weight by 10% from baseline with a weight loss goal of 1-2 lbs/wk over a six-month period.2 It is important to inform our patients that rapid weight loss is never healthy or safe. A healthy approach to weight loss might include putting together a plan that lays out the caloric intake restriction with exercise expenditure that equals 3,500-7,000 kcal/wk (1-2 lbs/wk weight loss). For example, a caloric restriction of 300 kcal/day with an increased exercise expenditure of 300 kcal/day for a total deficit of 4,200 kcal/wk.

During phase II exercise sessions, patients learn to develop a regular exercise habit. At this time, it is also important to educate them about caloric expenditure. How many calories are expended in 50-60 minutes of exercise? Are patients working at a level where at least 300 kcal are expended? What you will find is that if patients are working on average at a 2.0 MET level, they are expending approximately 140 kcal (assuming a weight of 81kg average) in 50 minutes and in 60 minutes, 170 kcal. At 3.0 MET level, they are expending approximately 215 kcal in 50 minutes and in 60 minutes, 255 kcal. At a 4.0 MET level, they are expending approximately 285 Kcal in 50 minutes and in 60 minutes, 340 kcal.

If one is walking outdoors on essentially a level surface at 2.0 MPH, the caloric expenditure is approximately 200 kcal/hr. (2.0 miles walked). If walking 3.0 MPH, the caloric expenditure is approximately 280 kcal/hr. (3.0 miles walked). On average, walking burns around 90-100 kcal/mile regardless of the walking speed. This actual number varies depending on extremes of body weight differences. Assuming a stride length of two feet, the 10,000 steps/day suggestion for health and fitness would equate to a distance covered of 3.7 miles (approximately 340-370 kcal expended).

In some individual cases, modification may be necessary in terms of weight bearing versus non- weight bearing exercise. Non-weight bearing exercise may be useful for the obese patient. Remember, that an exercise prescription for weight loss may differ from a prescription designed for cardiovascular improvements. A weight loss prescription often focuses on less intense activity for a longer duration, and on a daily basis. The importance of resistance training to increase muscle strength and endurance should also be stressed.

In summary, in order to achieve success, patients must make reasonable lifestyle changes to improve health and fitness that can be maintained over the long-term. It is worth reiterating – if weight loss is a primary goal, the patient must understand that one pound of stored body fat is equal to 3,500 kcal, and in order to lose just this one pound of fat, a 3,500 caloric deficit must be created through caloric restriction and exercise. A continued physical activity program appears to be the best predictor of long-term weight loss and its maintenance thereafter.¹ The question remains, how do we motivate our patients to continue exercising once they’ve completed phase II cardiac rehabilitation?

References
1. ACSM’s Guidelines for Exercise Testing and Prescription. 6th ed. Baltimore: Lippincott Williams and Wilkins, 2000: Chap 10 & 12.
2. Expert panel on the identification, evaluation, and treatment of overweight and obesity in adults. Executive summary of the clinical guidelines on the identification, evaluation, and treatment of overweight and obesity in adults. Arch Intern Med 1998; 158:1855-1867.

Write your answers on a piece of paper. Open your e-mail and send an e-mail message to Jane Hedgpeth CSCR Education Chairperson.jhedgpet_at_pacbell_dot_net Give her your name, title, e-mail address, license #, and phone #. Make a list 1-6 and indicate your answer to each question. Jane will e-mail your CEU certificate. This offer is free to CSCR members.

1. The most successful strategies for weight loss include calorie restriction, increased physical activity
and behavior modification designed to improve eating and exercise habits.
TRUE OR FALSE

2. The Body Mass Index (BMI) is often used to obtain a simple estimate of a person’s body composition and body weight classification.
TRUE OR FALSE

3. Caloric balance refers to the relationship between caloric intake and caloric expenditure.
TRUE OR FALSE

4. Increasing fat-free mass generally increases the basal metabolic rate (BMR).
TRUE OR FALSE

5. One pound of body fat is equivalent to approximately 3,500 kcal of energy.
TRUE OR FALSE

6. A weight loss prescription often focuses on less intense activity for a longer duration.
TRUE OR FALSE