Exercise plays a key role in health maintenance and disease prevention, physical and mental. Regularly practice any physical activity, improves and enhances general health and physical fitness and psychological. With these two statements are highlighted the consequences of exercising in the body.



All in all, exercise can be distinguished:

aerobics, in which we placed the running, swimming or aerobics, with which increased the heart rate and respiratory

anaerobic, such as those in the ground or fixed resistance machines gym. With the first, it promotes cardiovascular fitness and lose weight, and the second is improved muscular fitness and strength.

In this article we discuss the gym and more specifically, weight training, which as physical exercise, go of course, in the western disciplines.

The gym

Among the options, therefore, for physical exercise, we can choose to attend a specialized sports center, fitness center, which offers a wide variety of activities, among which we select those that satisfy us with regard to individual needs and possibilities of physical activity and fitness.

In recent times, the motivation of the person who goes to a gym is not only an improvement in body image and physical performance, but has turned to improving and maintaining good health. To this add that the gym also has now become a rehabilitation center where they treat mild and moderate disorders of the musculoskeletal system, especially back pain . In the gym, and through specific exercise programs, can improve pain in the vast majority of patients and even those are better when treated in healthy people. The exercise, in these cases, you must practice for life, to maintain continuous improvement of the condition, always individually adapted.

Returning to a general, exercise training in a gym is recommended for people who need discipline and motivation to keep fit, allowing you to work with its own rhythm, with the help of a trainer to advise on the maintenance program. But always bearing in mind that a gym class is beneficial if it can continue to completion, learning how to dispense the pace to it.

It is important to consider the coach's motivational skills and personal values if the class level is appropriate and in doing so, it is advisable to test various offers.

Each activity must consider the benefits and possible risks, and the frequency and the training is advised. And so we have circuit training, aerobics, step, ballroom dancing, ballet and weight training. On the latter we will stop in this chapter with more detail.

Weights

Weight-bearing exercise is repeated movements that strengthen the muscles, enhancing their strength and making it more resistant, thus shaping the body. Its basic principle is to overload the muscles to develop when it supports and increases the weight over time. The muscles are prepared by fixed resistance machines, free weights and exercises in soil. Combining this with aerobic anaerobic activity as well as stretching, driving the body to general fitness.

The weights are recommended from age 18 to older, more often two to three times weekly, with the possibility of training days in a row if you train upper body one day and lower the next day.

Its benefits have been described, highlighting the general increase in muscular strength and endurance, working multiple muscle groups simultaneously. But not only used the weights for this purpose, but also is a good method of rehabilitation muscle and joint injury in which muscles and joints have been subjected to long periods of immobilization or rest. But keep in mind that weightlifting and bodybuilding exercises generally do not offer all the benefits of sport. It is therefore recommended to coordinate with other exercise.

The exercise machines must be adjusted individually, as appropriate, to avoid possible injury production. At the beginning of each session in the gym, warm up exercises should be performed for each muscle group along with gentle stretching exercises to prevent stiffness and other injuries.

You should go slowly ...

It is certainly advisable to start this exercise with light weights, working every major muscle group, legs, arms, anterior chest (chest), back, buttocks and abdomen, with two sets of fifteen to twenty, later moving to a weight that is heavy enough to fatigue the muscle exercised within a maximum of ten repetitions, and practicing as two series. Thus, we will work both endurance and strength training. You should not forget the cool-down exercises and relaxation after exercise, stretching the muscles slowly and gradually.

... And gradually increase

Finally, it should be noted that progress, we lift weights that are increasingly kilos. If we are prepared for more strenuous exercise, it is advisable to have a coach who can guide us on the proper progression for the program to follow.

But beware:

It is important to remember that poor technique can lead to serious injury and that besides the usual sportswear, we can help optionally with lumbar sash and gloves.

The chief functions of the colon are the collection, dehydration, transit and temporary storage of stool. The colon is not absolutely essential to life, since people can survive without it after removal--but the study of people who have had to have their large bowels removed for medical reasons reveals deficiencies which shed light on its very important functions. Lack of a colon leads to the following conditions: 1) excessive loss of sodium and chloride ions and water; 2) chronic dehydration and hyponatremia (low sodium levels in the blood); 3) decreased production of urine by the kidneys in an attempt to conserve water. The latter situation may lead to increased production of kidney stones.

The colon has a remarkable efficiency and capacity to reabsorb water and sodium and plays a vital role in protecting the human body against hyponatremia, even when oral intake of sodium is low. Up to ninety percent of the water which reaches the colon is reabsorbed. The volume of stool which reaches the colon averages about one and a half liters per day, but can amount to as much as five liters daily. Although colon function is primarily to absorb water and is exquisitely designed to reduce back diffusion of water and fluid, it is also capable of producing or secreting fluid, particularly in disease. Thus, diarrhea is not simply an absorption failure phenomenon, but may be an active process brought on by illness. Most absorption of water and electrolytes is accomplished in the proximal (upstream) portion of the colon, while comparatively little or none is absorbed in the rectum.

Lymphoid cells are interspersed throughout the tissues of the colon while lymph nodes are found in networks adjacent to or just outside of the bowel walls. Lymph nodes are part of the body immune system and are very important in the defense against infections from viruses and bacteria and in the containment of cancer cells. Hundreds of lymph nodes are present in all parts of the body, and like a microscopic FBI, they provide a form of biological surveillance against the anarchy that can result from infection and malignancy. Lymphatics are milky vessels that drain the milky fluid known as lymph from tissues to the lymph nodes.

Draining the colon are three main groups of lymph nodes: the paracolic nodes that essentially border the outside surface of the colon; the intermediate nodes that skirt along the major arteries supplying the colon; and the central nodes that are rooted near the aorta. The lymph fluid drains through this network of nodes and eventually finds its way into a large sac (or reservoir) of fluid known as the cysterna chyli which then drains into another large vessel known as the thoracic duct. The thoracic duct flows into the left subclavian vein that carries blood and lymph into the vena cava from whence they are recycled into the arterial side of circulation through the heart.

The lymphatic network of the colon is important with respect to the role they play in both inflammatory bowel disorders and with respect to that which is played in cancer.

The blood supply of the colon includes arteries which deliver blood rich in oxygen and other nutrients to the bowel tissues and veins which return deoxygenated (oxygen poor) blood to the lungs and heart. Surgical decisions regarding resection of colon cancers are heavily dependent on the anatomic location in the colon and on the blood supply to that particular segment. The chief arterial sources are the superior mesenteric artery and the inferior mesenteric artery, which branch off the aorta, the very large artery that comes directly from the heart. The superior mesenteric artery through its branches provides blood to the small bowel, right colon and transverse colon. These branches are the ileocolic artery that supplies the cecum, appendix and final portion of the ileum; the right colic artery that supplies the right colon and the middle colic artery that feeds the transverse colon. The inferior mesenteric artery through the left colic artery branch feeds the left colon and through the sigmoidal arteries and the hemorrhoidal arteries supplies the rectum. Each artery has a complementary vein by the same name.

The columnar absorptive cells are tall, and as their name implies, have highly refined internal architecture which suits them for the purpose of water and electrolyte absorption. The goblet cells, on the other hand, are primarily perfected as mucin producing elements. There are at least a dozen and a half or more different types of enteroendocrine cells, which secrete (discharge) hormone-like peptides into the adjacent lamina propria and into the lumen of the bowel. These peptides have a variety of functions important to digestion and the motility or propulsive action of the colon.

The lamina propria is a mesh of tissue, primarily containing collagen, which is a connective type of tissue and occupies the space between crypts in the epithelium and the muscularis mucosa. Interestingly, it also contains lymphocytes and other cells of the immune system (called mast cells, plasma cells, macrophages, eosinophils and fibroblasts). The exact role and function of these cells here is not clear. Blood and lymph vessels, as well as nerve fibers, are found here.

The thin muscularis mucosa is situated at the base of the lamina propria and is spread like a sheet of fine filo dough.

It is the epithelium of the colon which is perhaps most important to the understanding of colon cancer, for it is here where the vast majority of colon cancers begin. Colon epithelium has a flat appearing surface, but it is glandular tissue, primarily, and is characterized anatomically by long, thin microscopic pits known as crypts. (They are sometimes also called the glands of Lieberkuhn after the eighteenth century German anatomist who first described them.) These crypts measure about half a centimeter in depth. They contain three types of cells, known as the columnar absorptive cell, mucous-secreting goblet cells, and enteroendocrine cells.

There is an amazing turnover of epithelial cells, with the columnar absorptive and goblet cells having a lifetime of only a few days. These cells begin as undifferentiated (meaning without any recognizable distinguishing characteristics) cells in the deeper zones of the crypts and they move up to the surface where they take on their recognizable features. When cells reach the flat surface of the epithelium they begin to degenerate and eventually slough off into the lumen and become part of waste eliminated. The life cycle of a cell in this process is four to six days. The enteroendocrine cells probably survive a little longer than their columnar absorptive and goblet cell counterparts and probably migrate up the crypt (independently of them) as well. The epithelium lining the colon is thus replaced completely every four to six days and because of the constant renewal process that goes on in the bowel, the epithelium is particularly sensitive to noxious substances. [It is because of this constant turnover and sensitivity in the gastrointestinal tract that nausea, vomiting and diarrhea are common features of chemotherapy drug and radiation therapy toxicity.

The colon contains four layers (or coats) of tissue. The outermost tissue layer, much like a membrane, is the serosa. Attached to the outside of the serosa are fatty fragments known as the appendices epiploicae. Deeper tissue layers include the outer muscular layer called the muscularis propria which provides the muscular contractions to propel feces, a submucosal layer containing nervous tissue, blood and lymph vessels and connective tissue, and the innermost mucosa, which has three components, the epithelium, the lamina propria and the muscularis mucosae.

The muscularis propria has two distinct groups: the longitudinal taenia coli that run on the outside as three separate bands from the cecum to the rectum, and the circular inside layer of muscle. Interspersed between these two layers of muscle are plexuses, or networks, of nerve tissue known as the myenteric plexus of Auerbach. These nerve fibers are part of the autonomic (which essentially means self-controlling) nervous system and help bowel function to proceed (for the most part) effortlessly. The taenia are about one-half to one centimeter in width. The muscular tissues separate outpouchings of the bowel known as haustra which give the colon a characteristic segmented appearance. On plain x-rays of the abdomen, the colon often is seen to contain air while the small intestine usually has little or no gas in it. The colon can usually be further identified on x-rays by the characteristic appearance of the haustra.