Chapter 10


Physical exercise can be defined as deliberate muscular activity (work) performed regularly and of sufficient intensity and duration to maintain or improve health. Not coincidentally, exercise almost always improves rate, total amount and long-term success of weight loss (more specifically of body composition). Along with dietary change, exercise is one of the two major facets of every sensible weight loss plan.

Given the extreme importance of exercise, I will devote a lot of attention to it here. I'll try to tackle most of the issues that I have encountered over twenty years in bariatric medicine.

Exercise is the MAIN control we have over calorie output:

We can modify calorie intake through dietary change, and we can slightly increase the thermic effect of food (TEF) through macronutrient choices, but our primary control over how many calories we burn lies with exercise. This means, of course, that with enough exercise we could eat anything and still lose weight. This is rarely practical however since it often requires upwards of 2 hours of exercise daily. More appropriately, exercise can allow us to enjoy a wider variety of foods with less concern for strict control. In other words, reasonable dietary change combined with moderate regular exercise makes weight loss a whole lot easier. Obviously it can also make weight loss happen faster, but where exercise REALLY makes all the difference is with weight maintenance.

Exercise, more than anything else you do, will determine long-term success in weight loss:

I often tell patients "you can lose weight even if you don't exercise, but unless you start doing it, you won't keep it off". It's generally about that simple. Time and again, people who exercise live thinner and healthier lives than people who do not. We'll explore why this is true as we progress through this chapter.

Exercise and Calories

Exercise involves muscular contraction used to perform physical work. To put it another way, exercise requires energy. The energy required for exercise comes from breaking the chemical bonds of substances stored in the body. Generally these substances are either glucose (sugar) or fat, but in any case, breaking these substances down involves "burning" energy or calories. Exercise is work and work requires energy. Exercise burns calories.

Direct Burn, Afterburn, Metabolism and the Thermic Effect of Food

Exercise helps us burn calories in three basic distinct ways:

1.     Direct Burn: The largest source of calorie-burn from exercise happens WHILE the exercise is being performed. We can call this the "direct burn" of exercise. To put it another way, if you run ten miles, most of the calories that you will burn are burned DURING the run.

2.     After-Burn: Also called EPOC (Excess Post-Exercise Oxygen Consumption) is calorie burning caused by intense exercise that happens AFTER the exercise has stopped and usually continues for several hours. This is a subject of great interest today among exercise physiologists and authors of weight loss books. We'll talk more about it later.

3.     Metabolism: Exercise also increases resting metabolic rate or "Basal Metabolism". It does this because, over time, exercise tends to increase lean body mass, specifically muscle mass. Since muscle, pound per pound, burns more calories AT REST than fat burns at rest, an increase in muscle means increased resting metabolism. Because resistance training (weight training) is the most efficient way to increase muscle mass, it is also the most efficient way to increase resting metabolism. Still, the magnitude of this effect is small as compared with direct burn and after-burn.

4.     Thermic Effect of Food: This is a subject that is covered more in the diet sections of this book, but it also has relevance to exercise because exercise appears to slightly increase the thermic effect of food. In other words, regular exercise causes your digestive system to burn more calories after a meal. The effect however, is very small.

Aerobic and Anaerobic Exercise:

Exercise can be done three ways:

1.     Aerobically: In aerobic exercise, large numbers of big muscles are contracting slowly enough that they never outpace their ability to use oxygen. Aerobic exercise therefore tends to be sustainable; people can keep going for more than a few seconds or minutes without a break.

2.     Anaerobically: Anaerobic exercise occurs when we isolate individual muscle groups and work them so hard that they "out-work" their ability to absorb and use oxygen. This is weight training. When a muscle can't get enough oxygen to keep-up with work load, it can continue contracting, but not for long. What happens is that without oxygen, the muscle can still get energy from glucose (sugar) stored in the muscle, but as the glucose is used, without oxygen, it leads to a build-up of lactic acid in the muscle. Lactic acid is what accounts for the "burn" of weight training. Excess lactic acid in muscle hurts and the more acid, the greater the pain so that as it builds up, even the most powerful athletes must stop.

3.     High Intensity Circuit Training: Circuit training is aerobic and anaerobic. This is possible because the exerciser isolates muscle groups, works them anaerobically until lactic acid builds up in that muscle group and then quickly changes to anaerobically working a whole different muscle group that is lactic-acid free. The switch from one muscle group to the next is done so rapidly that the exerciser's heart rate doesn't begin to fall very much. When you see someone in a gym racing from machine to machine during a workout, THAT is high intensity circuit training.



Aerobic Exercise Intensity: Heart Rate:

The simplest way to judge the intensity of an aerobic exercise like walking or running by is one's heart rate during the exercise. Heart rate is nothing more than the number of times the heart beats in one minute. Aerobic exercise increases heart rate (and breathing rate) because aerobic exercise uses oxygen which comes from the air. In order to satisfy the increased oxygen demands of aerobic exercise, we have to breathe in more air and the heart has to pump faster to carry oxygen from the lungs to the muscles where it is needed.

Aerobic Exercise: Physical Condition:

Heart rate during exercise is dramatically affected by one's physical condition. Athletes like marathon runners can sustain a tremendously fast run at a fairly low heart rate while a sedentary middle aged man might achieve the same rate during a very slow walk.

Physical Condition Improves With Training

Physical conditioning through regular aerobic exercise whose intensity (speed) is gradually increased over many months leads to improved aerobic capacity. In other words, the marathoner will burn more calories in ten minutes than the middle aged man will even though they both have the same heart rate during that time. So, regular aerobic exercise causes our exercise to become more efficient so that we can burn more calories during the time that we are exercising.

Heart Rate and "Easiness"

Generally, the lower our heart rate is during an exercise, the easier it is to do. The less "miserable" we feel. Obviously a slow walk is easier than a fast run. This is why exercise feels so painful to people who are not physically fit.

Fitness and Easiness:

The fitter we are, the easier it is to burn a lot of calories through exercise. What used to feel like torture becomes enjoyable. This is why fitness and not just calorie burning is a major goal and benefit of regular exercise.

What IS Physical Fitness?

Regular exercise induces fitness in several ways.

1.     Stronger heart muscle

2.     Stronger breathing muscles

3.     Larger muscles

4.     More "slow-twitch" aerobic muscle

5.     Lower body fat

All these changes make aerobic exercise easier and more efficient (more gain for less pain).

How to Measure Your Heart Rate:

As noted earlier, heart rate is simply the number of times the heart beats in one minute. But how can you tell when your heart beats? Easy…. You feel for an arterial "pulse". Each time the heart beats, it squeezes blood out of the heart and into the circulation. This pushes the blood along and also creates a pressure wave or pulse that we you can feel with your fingertips. And you can feel it anywhere there is a large or medium-sized artery: the neck, the wrist, the ankle, etc. Generally the two best places to feel your pulse are the neck or the wrist. The trick is feeling in exactly the right place. Fortunately, the right place is easy to find as shown in the pictures below.


Once you have found the pulse you can count it. The time-consuming way to measure your heart rate is to count the number of pulses in a whole minute by looking at your watch while you count each pulse. When a minute has passed, voila!, the number of pulses you just counted is your heart rate. But, as I said, that takes a whole minute. A quicker way to check your heart rate is to count the pulses in fifteen seconds or a quarter of a minute. All you need to do then is multiply the number of pulses you counted over that fifteen seconds by four (fifteen seconds is a fourth of a minute) to get you heart rate.

There IS an even easier way to check heart rate: buy a heart rate monitor. Such devices are now sold in most sporting goods stores and they work by essentially "feeling" your pulse for you. The only downside to a heart rate monitor is that they cost money, but most sell for less than $50, some less than $20.

Exercising Safely

Performed properly exercise improves physical condition and health. Done poorly is can cause injury and harm health.

Acute (Sudden) Injuries:

These are injuries that you know about right away because they hurt or harm you right away. A good example is an ankle sprain. A list of common acute injuries is given below:

1.     Muscle soreness: In order to build-up muscle, to increase the amount of muscle we have, we have to injure it slightly through exercise. This leads to muscle soreness and especially to delayed muscle soreness (it hurts more the day AFTER than the day OF the exercise).

a.     Muscle soreness and delayed muscle soreness result from resistance training.

b.    The best way to minimize these problems is to start your resistance training program with light weights and then build-up the weight slowly over many weeks and months

2.     Blisters: Hardly a medical emergency, blisters are painful and commonly result from skin irritation caused by actions like gripping a bicycle handlebar on a long ride or walking (or running) too far in new or poorly-fitted shoes or boots.

3.     Ligament strain: Perhaps the most common exercise-caused injury, ligament strains occur when a tendon becomes overstretched but does not tear. This sort of injury commonly occurs in the ankles, sometimes in the wrists or arms but ultimately can occur anywhere a tendon is overstretched.

4.     Ligament Sprain: This is a step worse than strain. In a sprain, a ligament becomes partially or completely torn.

5.     Tendon Rupture: Worse still is the sudden rupture of tendon. This is where a tendon is torn completely so that there is no longer any connection between a muscle and a bone.

6.     Bone Fracture: A bone will fracture if it is stressed too much. This rarely happens in exercise except when people have accidents like skiing into a tree or dropping a weight on a foot. However, people with osteoporosis (bone thinning and loss) can sometimes fracture a bone performing ordinary tasks.

a.     Ligament strain, sprain, tendon rupture and bone fracture all generally result from exercise related accidents or from trying to perform feats far inexcess of one's physical condition.

b.    The best way to avoid these injuries is to exercise carefully and quit when you are tired. Most exercise accidents occur when people are exhausted.

7.     Heat Injury: Exercising outdoors in hot weather carries special risks. Sometimes we can heat-up faster than the body can manage. This is called "heat-stroke" and it can be deadly. Signs of heat stroke are dizziness, confusion, trouble walking. This is an emergency that requires immediate cooling by getting out of the sun, into shade or a cool building, lying down and splashing cold water on the body.

a.     Heat injury can occur with any exercise if performed in hot weather and especially when people are not "heat-acclimatized".

b.    Summertime exercise should be performed early in the morning or near sunset. Warm-up slowly and carefully monitor your own condition being especially observant of mental-status changes like dizziness, confusion, cloudy or muddled thinking or trouble walking. Stop exercising immediately and seek shade and help if you begin to show these symptoms.

8.     Dehydration: Like heat injury, dehydration tends to happen more often in hot weather, but unlike heat injury, it can also happen in very cold weather. Dehydration is the condition of having too little water in the body and occurs when we lose more water than we replace. In hot weather, we lose water by sweating but we also lose water through breathing and, of course, urinating. In any event, when we lose more than a few pounds (less than half of a gallon) of water, we become mentally and physically impaired. The way to prevent dehydration is to drink ample fluids before, during and after exercise. Sometimes drinking water is fine, other times, weight issues be damned, Gatorade or a similar sports drink is a wiser choice.

a.     Dehydration is a potential risk from any exercise any season, hot or cold.

b.    Drink plenty of fluid before, during and after exercise. Warning signs of dehydration include absent urination or urine that is highly concentrated and dark in color, dizziness, headache, nausea and vomiting. The only treatment for dehydration is rehydration with water or sports drinks like Gatorade.

9.     Hyponatremia (Low Sodium): If people drink too much water, they can dangerously lower their blood-sodium level. This can happen when marathon runners load up on water and keep drinking only water during a hot run. It can happen even absent exercise if people drink huge amounts of water. You may recall that a few years ago a woman died from drinking too much water in order to win a  radio station-sponsored contest in Sacramento, California.

a.     Hyponatremia happens when people over-consume water without salt. This happens when people exercise for a long time and only drink water.

b.    When performing any exercise for longer than about one hour you should consume electrolyte-replacement drinks like gatorade or balanced salt solution and not just pure water.

c.     You can make a pretty good and very cheap electrolyte replacement drink using one teaspoon salt, and two tablespoons sugar mixed into a quart of water. This will be faintly sweet and distinctly salty but it really works.

10.  Acute Asthma (Asthma Attack): Intense aerobic exercise causes rapid and deep breathing in order to keep-up with oxygen demand. This can irritate the airways of the lungs and, in some people, can trigger an "attack" of asthma. Patients who have a history of exercise-induced asthma may need to use an "inhaler" immediately before exercise

11.  Cardiovascular Accidents: In the long-term, exercise helps prevent the sort of heart disease that causes "myocardial infarction" or heart attack, but, in the short term, and in the case of people with existing heart disease, sudden intense exercise can work a sick or damaged heart so hard that

12.  Other injuries: Unless you exercise in a rubber room, there is always a chance of becoming seriously injured from traffic, crime, insects and many other "environmental" factors

Slow (Chronic) Injuries:

These are injuries that gradually get worse each time one exercises. An example is inflammation of the Achilles tendon caused (sometimes) by running. At first there is only vague pain. After a week or two the pain is worse and unless the sufferer stops running, a few weeks later, the pain is unbearable.

1.     Tendonitis

2.     Plantar fasciitis

3.     Sun damage

4.     Bone Spurs

Heart Safety:

Exercise works the heart muscle. Over time, this causes the heart muscle to become stronger and healthier, but in the beginning, especially in the case of someone with existing heart disease, sudden intense exercise can harm the heart by depriving the muscle of needed oxygen or by causing an irregular heart beat (arrhythmia).

Anaerobic Exercise Intensity: Time to Pain

The best way to judge the intensity of weight training is by how long it takes, by seconds or by "reps" to reach unbearable pain.


Neighborhood Walking

One of the simplest exercises involves walking out your front door and around your neighborhood. It is free, it is convenient and because it's walking, there is very low risk of injury. Let's look at the pluses and minuses of neighborhood walking:


1.     Convenient

2.     Free

3.     No commute

4.     Get to know your neighbors

5.     Get's you outside

6.     Low impact-low risk of injury



1.     Can be dangerous in a high-crime neighborhood

2.     Dogs can be a problem if neighbors leave them to roam

3.     Traffic can be dangerous if you walk along a busy street

4.     Some neighbors can be jerks

5.     Wintertime cold and darkness can make it very unpleasant


Trail Hiking:

One of the truly great things about life in New Mexico and especially in Albuquerque is that we have easy access to world-class hiking trails. The City of Albuquerque operates a number of "Open Space Parks" on our town's west-side, in the Rio Grande Bosque and throughout the foothills of the Sandia Mountains. Just beyond the City's "Open Space" in the Sandias lies the "Sandia Mountain Wilderness". This is land owned by the US Department of Agriculture's "National Forest Service". The Sandia Mountain Wilderness is vast and encompasses essentially all of the mountains' high peaks. It is one of the most beautiful and untouched wilderness areas on Earth and it's right in our own backyard. Most people who live here have never experienced this wilderness, but to look down on the city from the Sandia Crest is one of the great experiences in life.

Equipment Needed for Trail Hiking:

Depending on time of year and how far you plan to hike, you may need to invest in some basic outdoor equipment. Among the things you may need are:

1.     Good-fitting and comfortable footwear. Regardless of type of footwear you elect to use, make sure that the soles are good at gripping rough surfaces.

a.     Walking shoes: You can easily hike in decent walking shoes. I routinely hike to the Sandia Crest in $14 Costco shoes. Keep in mind though that shoes like this do not provide the same ankle support, protection from abrasion and snakebite that boots offer.

b.    Boots: Hiking boots are heavier than shoes but the offer more ankle support and better protection against abrasion and against snakebite. Boots are also better for very steep trails where they bend less and offer a better toe-hold.

2.     Water Carrying Equipment: It's not safe to be in the summer heat without lots of water. It's insane to hike in the wilderness without it. There are several ways to carry water:

a.     Bottle in your hand: The simplest way to bring water is to hold it in your hands. It's simple but annoying.

b.    Bottles in a backpack: Far better is to toss some bottles of water into a small backpack

c.     "Hydration Systems": These are backpacks that hold specially-made water-holding bags. The water bags (bladders) have a plastic tube attached to them that runs out of the backpack and over your shoulder to a mouthpiece that usually hangs at chest-level. The mouthpiece is designed to be water-tight until you gently bite on it at which point you can suck water out of the bladder and take a drink. This allows you to drink any time you like without the hassle of stopping, taking-off a backpack and pulling out a water bottle.

3.     Food: If you plan on hiking longer than about two hours, you should bring food with you.

4.     Hat: Choose one with a wide brim to keep your face out of the sun

5.     Sunscreen: Especially in summer, especially on your nose, ears, cheeks, lips and hands.

6.     Sunglasses

7.     Cell-Phone: For emergencies

8.     Warm Clothing: In winter

9.     Flashlight: Just in case you get caught in darkness.

10.  Map: A decent map of the trails you plan to hike is essential.


Swimming is a nearly perfect exercise because it provide a whole-body and low impact workout. It has the added effect, at least in cold water, of forcing the body to burn fat in order to stay warm. The only problem with swimming is that you have to know how. And you have to have access to a pool.

Water Aerobics:

Water aerobics offer at least the same exercise quality as swimming without the need to know how to swim. The downside here is that you still have to find a pool and find a class.


Biking offers a great aerobic workout and, if pedaling uphill, a very good anaerobic workout of most of the major leg muscles. Here is a list of the pros and the cons of bicycling regularly:

1.     Pro

a.     Excellent aerobic workout

b.    Builds leg muscles

c.     Fun

d.    Can be social or solitary

e.     Great scenery

f.     Can be used as transportation

2.     Con:

a.     Dangerous in traffic

b.    Requires a bike which costs money and needs maintenance

c.     Requires a helmet

d.    Can cause painful bruising of inner thigh in newcomers

e.     Not so fun in rain or during winter

Competitive Athletics:

Competitive sports fall into two categories: one-on-one (teamless) sports like tennis or racquetball and team sports like soccer or softball. There are similarities and differences between the two:

1.     One-on-One Sports: These sport require a single opponent and a venue. Sometimes it can be hard to find both.

2.     Team Sports: These activities require two teams who size depends upon the sport, a venue and often a referee.

Both approaches to competition CAN burn a lot of calories, but it depends heavily upon the sport in question. Here are some competative sports ranked, roughly, by number of calories burned (per hour).

1.     High Calorie Burn

a.     Tennis

b.    Racquetball

c.     Basketball

d.    Soccer

e.     Rugby

f.     Water polo

2.     Moderate Calorie Burn

a.     Volleyball

b.    American football

3.     Low Calorie Burn

a.     Baseball/softball

b.    Golf

c.     Table tennis

d.    Bowling