Making a Profit…Returns on Your Energy Expenditure

May 2007 – Vol. 11, No. 5

Editors: Janet M. Pollard, MPH; and Carol A. Rice, Ph.D., R.N.

A profit can be defined as the excess of returns over expenditure in a series of transactions. So why talk about profit here? Because, the returns on your energy expenditure can be higher than many people realize. When you expend (use) energy in exercise or physical activity of any kind, you make a profit on your health. We often think of physical activity as simply a way to “look” better—appearance being the primary goal. Changes in appearance often do result with physical activity, but there are so many more payoffs to becoming fit.

In this issue of HealthHints, we’ll look at some of these payoffs—why you might want to achieve them and what it takes to get them.

Reducing Disease: The importance of physical activity…at all ages

“Physical inactivity and dietary patterns are second only to tobacco use as a leading cause of preventable death in the United States.¹ The top three lifestyle choices, 1) tobacco use, 2) poor diet and physical inactivity, and 3) alcohol consumption, account for over a third of all deaths each year.”² These three preventable causes of death result in nearly 900,000 premature deaths each year.³ “Physical inactivity is also a leading contributor to morbidity and disability.”¹ “Like tobacco, obesity and inactivity increase the risks for the top three killers in the U.S.: heart disease, cancer, and cerebrovascular ailments including stroke.⁴ Obesity and inactivity also increase the risk of diabetes, the sixth leading cause of death.”⁵ In fact, “poor nutrition and physical inactivity are fueling an epidemic of obesity that is driving diabetes rates up and the age of diabetes onset down.”⁶ Obesity may soon be the leading cause of preventable death in the U.S., with over 60 percent of adults overweight or obese and nearly 13 percent of children.⁷ “The prevalence of excess weight and obesity has nearly doubled among children and adolescents since 1980 and is increasing in both sexes and among all adults.”⁷ “For the first time in our nation’s history, today’s generation of children may have poorer health than their parents—a decline caused by obesity.”⁶ “The trends are already associated with major increases in the prevalence of conditions such as asthma and type 2 diabetes mellitus in children.”⁷

The Payoffs: Changing life quality across the lifespan

For many of us, the question boils down to this—why should I exercise? Why should I schedule exercise into an already busy day when I could be doing something else profitable with my time? Answer: There are big payoffs! These payoffs include:

associated with disease,
improved physical function, and
psychological benefit.

Let’s talk about what you get for your exercise efforts, and I think you’ll see that your health profits outweigh the potential expenditures on your part.

Reduction in risk factors associated with disease

Regular physical activity helps prevent obesity, heart disease, hypertension, diabetes, colon cancer, ischemic stroke, and premature mortality.⁸

Obesity: Physical activity may reduce the incidence of obesity. This is of particular importance in disease reduction since obesity puts us at higher risk for cardiovascular diseases and non-insulin dependent diabetes. Reducing total body fat, particularly abdominal fat (fat carried on the stomach rather than the thighs or buttocks), is crucial. Abdominal fat is a known risk factor for insulin resistance related to diabetes and cardiovascular diseases. “Physical fitness may favorably affect body fat distribution,”⁹ resulting in “more beneficial redistribution of body fat in both sexes.”¹⁰ In fact, “physical activity is inversely associated with obesity and intra-abdominal fat distribution, and recent studies have demonstrated that physical training can reduce these body fat stores.”¹⁰

Heart Disease: “Regular physical activity or cardiorespiratory fitness decreases the risk of cardiovascular mortality in general and coronary heart disease mortality in particular.”⁹ Regular physical activity improves blood pressure, blood circulation, and cholesterol¹¹—all of which can increase our risk if not kept in control. “The benefit derived from physical activity occurs at moderate levels of physical activity or cardiorespiratory fitness and increases with increasing levels of physical activity or higher levels of fitness.”¹⁰

Hypertension: “Regular physical activity prevents or delays the development of high blood pressure, and exercise reduces blood pressure in people with hypertension.”⁹ Hypertension is associated with a markedly increased risk of developing heart disease¹²—the number one killer in the U.S. “Physically active and fit individuals with hypertension have markedly lower rates of mortality than sedentary, unfit hypertensive individuals.”¹²

Diabetes: “Regular physical activity lowers the risk of developing non-insulin dependent diabetes mellitus.”⁹ In patients with non-insulin dependent diabetes mellitus, exercise may improve insulin sensitivity and assist in diminishing elevated blood glucose levels into the normal range.¹⁰ Studies also suggest that “insulin sensitivity and rate of glucose disposal are related to cardiorespiratory fitness even in older persons.”¹⁰ Basically, physical activity just helps insulin work better.¹¹ In fact, “people with pre-diabetes can prevent the development of non-insulin dependent diabetes mellitus by making changes in their diet and increasing their level of physical activity. They may even be able to return their blood glucose levels to the normal range.”¹³

Colon Cancer: “Regular physical activity is associated with decreased risk of colon cancer.”⁹ Research on both occupational and leisure-time physical activity suggests that physical activity has a protective effect against the risk of developing colon cancer.¹⁰ Physical activity may also reduce the risk of several other types of cancer, including breast, endometrium (uterus), and prostate cancer.¹⁴ Research in these areas is ongoing.

Stroke: Some scientific data also indicate that “physical activity, including moderate-intensity exercise such as walking, is associated with substantial reduction in risk of total and ischemic stroke in a dose-response manner,”¹⁵ meaning higher doses (more exercise) resulted in more risk reduction (the body’s response).

Improved physical function

In addition to reducing disease risk, regular physical activity, including endurance, strength, and flexibility training, can help us maintain or improve physical function. “Regular physical activity improves aerobic capacity, muscular strength, body agility and coordination, and metabolic functioning, exemplified by improvements in bone density, lipid profiles, insulin levels, and immune function.”¹⁶

Endurance training: Endurance training (e.g., aerobic activities like walking, bicycling, swimming) can help maintain and improve cardiovascular function¹⁷ (e.g., the workings of your heart, lungs, and blood). This means an improved ability to climb stairs or climb a mountain; keep up with children or grandchildren.

Strength training: Strength training (e.g., weight bearing and resistance exercises) helps offset the loss of muscle mass and strength typically associated with normal aging.¹⁷ This means the ability to carry a box to your neighbor down the street, carry a sack full of groceries, or climb a set of stairs because you have enough leg strength to do so. While “there is promising evidence that strength training and other forms of exercise in older adults preserve the ability to maintain independent living status and reduce the risk of falling,”⁹ “weight-bearing physical activity is [also] essential for normal skeletal development during childhood and adolescents and for achieving and maintaining peak bone mass in young adults.”⁹

Flexibility training: Flexibility training (e.g., range of motion exercises) is also important in maintaining functional capacity, often in the things we think about least, such as being able to button the back of our dress, reach a high shelf, or bend down to pick up something from the floor because our body has its full range of motion.

“Regular physical activity is necessary for maintaining normal muscle strength, joint structure, and joint function.”⁹ It is also important in the reduction of osteoporosis and fall-related injuries. It improves:

bone health (reducing the risk for osteoporosis),
postural stability (reducing the risk for falls and associated injuries and fractures), and
flexibility and posture (increasing functional capacity, such as reaching a high shelf or buttoning the back of a dress).¹⁷

In addition to preserving or maintaining normal muscle and joint function among those who have healthy muscles and joints, regular physical activity of moderate intensity has also been found to raise the pain threshold, improve energy level, and improve self-efficacy among persons who already have joint and muscle problems such as osteoarthritis.¹⁰

Psychological benefit

Evidence suggests that involvement in regular exercise can also help:

preserve cognitive function,
alleviate depression and anxiety, and
improve the concept of personal control and self-efficacy.

Cognitive function: A small number of studies have shown a positive association between regular physical activity and cognitive performance on tasks such as math, acuity, and reaction time.¹⁰

Depression/Anxiety: “Physical activity appears to relieve symptoms of depression and anxiety and improve mood,”⁹ and “may reduce the risk of developing depression….”⁹ (See also “Our Mental Health Status”.)

Personal control/Self-efficacy: Some of the most direct effects of physical activity on health-related quality of life are in the areas of psychological well-being, including perceived abilities to function, as well as perceived symptoms or physical states (e.g., pain, fatigue, etc.).¹⁰ Among people compromised by ill health, physical activity appears to improve their health-related quality of life by enhancing their psychological well-being and by improving their ability to perform activities of daily living.^9,10 In fact, people “who have lower levels of mental or physical health may have the most to gain from physical activity, since they have more room to improve their health status than people already possessing good health.”¹⁰

Physical activity can also relieve stress, increase energy, and help us sleep better¹¹—all of which influence our physical, as well as our psychological, functioning.

The Returns…Worth exercising for

When we look at physical activity from the standpoint of what we can or can’t do, or what we will or won’t be able to do in the future, the cost of being physically active seems far lower than the cost of functional incapacity. All of “the benefits associated with regular exercise and physical activity contribute to a more healthy, independent lifestyle, greatly improving the functional capacity and quality of life”¹⁷ across the lifespan. By simply starting to exercise and sticking with it to expend energy each day, you have the opportunity to reduce diseases like heart disease, cancer, stroke, and diabetes. You also create a better way of life for yourself by helping to maintain your weight, bone structure, and muscle mass. Additionally, exercise helps contribute to healthy mental states, keeping us functioning well cognitively and keeping our moods in check. If you are thinking about putting off exercise for another day, think again about what you are paying in health returns in the long-run. With an investment in physical activity each day (even a small investment—in short bouts), you can make a profit on your health and functional capabilities for a lifetime.

(“Definitions of Terms” used in this newsletter are located at: http://fcs.tamu.edu/health/healthhints/2007may/terms.pdf.)

Our Mental Health Status: The importance of psychological benefits

“The annual prevalence of mental disorders in the United States population is high.”¹⁰ We often think of mental health issues as only the most severe cases—those that keep an individual from functioning in society or requiring individual assistance on a daily basis. In reality, “nearly three out of 10 persons 15–54 years of age who live in households report having had a mental disorder during the previous year,”¹⁰ which come in the form of affective (mood) and anxiety disorders. “More than one out of 10 adults suffers from a depressive disorder in any given year; between 13 and 17 percent suffer from an anxiety disorder.”¹⁰

When we see this picture of our health, the importance of the psychological as well as the physical benefit of exercise is evident. Scientific “literature suggests that physical activity helps improve the mental health of both clinical and non-clinical populations. Physical activity interventions have benefited persons from the general population who report mood disturbance, including symptoms of anxiety and depression, as well as patients who have been diagnosed with nonbipolar, nonpsychotic depression.”¹⁰ Additional evidence suggests that physical activity may contribute to primary prevention of mental health problems—protecting against the development of depression.¹⁰

Definition of Terms

Cardiorespiratory Fitness: Fitness (good health) of the heart and lungs.
Cardiovascular Disease: Diseases that involve the heart and blood vessels (arteries and veins).
Coronary Heart Disease: A narrowing of the small blood vessels that supply blood and oxygen to the heart; the end result of the accumulation of plaques in the walls of the arteries that supply the muscle of the heart.
Hypertension: Also called high blood pressure, hypertension results when your blood pressure is continually elevated. Blood pressure is the force of your blood pushing against the walls of your arteries. High blood pressure usually has no symptoms, but it can cause serious problems such as heart disease, stroke, and kidney failure.
Incidence: Number of new cases of a condition or disease that arise during a specific period of time, such as a year.
Non-Insulin Dependent Diabetes Mellitus: Also called type 2 diabetes or NIDDM, non-insulin dependent diabetes mellitus is a long-term condition where the body is unable to properly regulate the amount of glucose (simple sugar) in the blood.
Morbidity: Total cases of a disease, or the severity or degree of a disease in a population.
Mortality: Death or death rate.
Prevalence: Total number of cases of a disease in the population at a given time.
Sedentary: Inactive.
Self-efficacy: Belief in one’s capability to perform in a certain manner or attain a certain goal.

Sources:
U.S. National Library of Medicine and National Institutes of Health (2007). MedlinePlus. Retrieved May 17, 2007. From http://medlineplus.gov/.
Wikipedia (2007). Retrieved May 17, 2007. From http://en.wikipedia.org/wiki/Main_Page.

This document is meant for educational purposes only and is not intended to replace the advice of your doctor or other health care provider.

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