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Why Exercise?

Physical Health for Chronic Disease


​There is a rapidly growing body of research and evidence linking increasing physical inactivity with the rising incidence of chronic disease, with height and weight ratios beginning to increase progressively during the industrial revolution of the 19th and into the 20th centuries to the present 1. Early human ancestors were hunter-gatherers, and with the advent of the fire, they would become more social, increase cognitive capacity, and eventually evolve into larger communities, which led to farming and the agricultural evolution 2. This would eventually make way for the industrial revolution, and a steady growth of consumerism developed in the 19th century 3. Then adding in the technological advances making food increasingly easy to acquire and consume led to high consumption rates, but industrialization and technology has also brought many conveniences that increased rates of inactivity and low energy expenditure 1. ​Physical inactivity, especially when coupled with over-consumption of food, contributes to the rising incidence of chronic diseases such as musculoskeletal disease, diabetes and obesity, and atherosclerosis and heart disease within the United States 4. Maintaining healthy levels of physical activity improves the health of muscles, bones, joints, and metabolic health by maintaining macro-nutrients at healthy levels in the body, decreasing oxidative stress and inflammation, as well as maintaining healthy joints, bone strength, and muscle quality 5.

​Physical inactivity is important not only in individual health, but chronic disease places a heavy burden on the health care system. In the United States, about 80% of Americans fall short of the federal recommendations for physical activity 6. Physical inactivity increases the risks of chronic disease such as arthritis, osteopenia, sarcopenia, and heart disease. This places a heavy burden on the health-care system, contributing to the statistics showing that the United States has some of the most expensive health care costs and high rates of chronic disease, even with the leaps and bounds that the country has made in technological advances 7.


​So why increase physical activity?

It is also important to understand basic physiological principles behind physical health and fitness. Each individual will be at different stages along the continuum of health, and there will be a number among that population that will have special needs due to underlying disease or other medical condition that must be addressed, managed, or monitored. These include heart disease, osteoporosis, arthritis, cancer, diabetes, or any number of different pathological conditions that can prevent or limit different types of physical activity 8. It is advised to have regular physical exams and screenings to minimize risks of disease, and also to mention to the primary care physician of any intention to increase physical activity, and what type, in order to have medical guidance to also help minimize any other risks to health, such as fractures, sprains, strains, dislocations, heart attacks, or strokes 4, 8.


The physical health of the bones, joints, and muscles in the human body generally develop on a bell curve, growing and getting stronger through the first quarter of life, plateauing, then gradually declining beginning around the 4th and 5th decades of life 4. In the absence of any other pathology, the development and decline of the human body’s physical health is directly affected by the physical stress placed upon it through the lifetime 4. As defined by Wolff’s Law, bones adapt based on the stress placed upon them 5, meaning that they can get stronger with increased bone formation with increased physical demand, such as weight lifting. The joints in the human body are meant for movement, and one key factor in maintaining their health is imbibition, where movement of the joints pulls in fluids and nutrients 5. Muscles in the body play a very important role. Not only do muscles produce movement, they also help maintain metabolism, burning calories when in use and when at rest 5. This is important to understand, as the energetics of the body can play a critical role in chronic metabolic disease. In simple terms, the primary source of fuel for exercising muscles are carbohydrates, which are plentiful in the American diet, but any excess will be put into storage as fat, and increased body fat increases risks of inflammation and arterial plaque building up, which would increase the risks of atherosclerosis, heart attack, and stroke 8.


At the beginning of any physical activity program, it is important to start with stabilization phase, which focuses on teaching the body to engage important muscles that support the movement of the body. An example of this is being able to balance on one foot, by teaching the brain to engage these stabilizing muscles, there is a decreased risk of loss of balance 4. An important risk to older adults is a hip fracture from losing balance and falling 9, 10. By increasing stability and the quick psycho-motor response to the stabilizing muscles in the hips, the risk of falling and subsequently the risk of hip fracture would decrease. By combining the basic principles of body mechanics and physiology and personal training philosophies, increased physical fitness and decreased risks of chronic disease can be easily achieved.


​When most people hear about physical fitness, they may automatically think about going out and joining a gym with monthly dues. They may even join the gym with expectations of commitment to fitness and taking control of their health, but evidence shows that a large number will gradually taper off of their gym attendance and eventually quit or pay for their memberships without utilizing it 11. It is not absolutely necessary to join a fitness club or to seek professional instruction, but it is important to understand that inexperience or lack of guidance can potentially lead to injury or undesirable results. A quick search on the internet or perusing the health and fitness section at the local bookstore will reveal numerous sources available to explain and demonstrate different ways to exercise at home.


With professional fitness and personal training, instruction generally utilizes foundational principles and progressions, starting with a stabilization stage of training, followed by the strength phase, and finally the power phase. The stabilization principles describe exercises which utilize more compound movements that recruit not only the primary moving muscles, but also the secondary support muscles 5, 12. An example of this will be the basic push-up, but on rather than on a hard and stable surface, the exercise can be performed yoga mat, which increases the activation of the secondary muscles that stabilize the wrist and elbow 12. This phase focuses on muscle firing patterns from the brain, or teaching muscles to turn on, as well as teaching more muscle fibers to engage 4. Exercises during this phase are low intensity but performed with a higher volume of repetitions. By the end of this phase, muscle activation and the volume of muscle fiber recruitment allows for the advancement to the strength phase, which not only increases the volume of muscle fibers activated learned during the stabilization phase, but also increases their endurance, size, and strength 4. By the end of this phase of training, there will be noticeable increases in strength and endurance, as well as some evidence of increased tone and definition. While strength and endurance results will be consistent for everyone, the visual results can vary from person to person, and will depend on what their fitness levels were and body composition prior to starting their training. ​Following the stabilization and the strength phases is the power phase. The power phase is designed to increase explosive force of muscle activation, and the high intensity exercises are important in the performance of many athletes, as well as contributing to healthy metabolism and the reduction of inflammation within the body 13. With these phases complete, an undulating phase is utilized, where the first 3 phases can be repeated indefinitely to maintain healthy fitness levels and habits. There are many muscles in the body, the and an even greater number of ways to exercise and engage them. This means that workouts can be customized to fit the needs and goals of each individual, making them more personalized and fun. At the end of the day, for most people, they will only maintain their workout programs if they enjoy them. Studies have also shown that motivation and adherence to a physical activity program is strongly influenced by the level of fun perceived while participating in the activity 14. It is important for each individual to understand the importance of physical activity and the implications of inactivity, and to then determine which options are best for their needs, whether it is home exercise, hiring a trainer, or joining a gym or fitness studio.


1. Caballero B. The Global Epidemic of Obesity: An Overview. Epidemiologic Reviews. January 2007;1:1-5.

2. Myhrvold N, Young C, Bilet M. Modernist Cuisine: The Art and Science of Cooking: Volume 1 - History and Fundamentals. Bellevue: The Cooking Lab; 2011.

3. Corbett PS, Janssen V, Lund JM, Pfannestiel T, Vickery P. U.S. History. Houston: OpenStax; 2017.

4. Clark MA, Lucett SC, Sutton BG. NASM Essentials of Personal Fitness Training 4th Edition. Baltimore: Wolters Kluwer | Lippincott Williams & Wilkins; 2012.

5. Exercise Physiology: Nutrition, Energy, and Human Performance. 7th ed. Baltimore: Lippincott Williams & Wilkins; 2010.

6. Robert Wood Johnson Foundation. Physical Inactivity in the United States. August 2017:1-108.

7. Schneider EC, Squires D. From Last to First — Could the U.S. Health Care System Become the Best in the World? The New England Journal of Medicine. September 2017:901-904.

8. Kumar V, Abbas AK, Aster JC. Robbins Basic Pathology. 9th ed. Philadelphia: Elsevier Saunders; 2013.

9. Wehren LE, Magaziner J. Hip fracture: risk factors and outcomes. Current Osteoporosis Reports. September 2003:78-85.

10. Marks R. Hip fracture epidemiological trends, outcomes, and risk factors, 1970–2009. International Journal of General Medicine. April 2010;3:1-17.

11. DellaVigna S, Malmendier U. Paying Not to Go to the Gym. The American Economic Review. April 2015;3:694-719.

12. Lauren M. You Are Your Own Gym: The Bible of Bodyweight Exercises. New York: Ballantine Books; 2011.

13. Teta J. Exercise is Medicine: The Anti-Inflammatory Effects of High-Intensity Exercise. Townsend Letter. November 2006:82-86.

14. Ryan RM, Frederick CM, Lepes D, Rubio N, Sheldon KM. Intrinsic Motivation and Exercise Adherence. International Journal of Sports Psychology. 1997:335-354.

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