Exercise

The word exercise can mean the following:
 * An activity that is done with a specific motive to improve some component of physical fitness.
 * A setting in action or practicing.
 * Any activity designed to develop or hone a skill or ability.
 * Physical exercise

Physical exercise
Physical exercise is the performance of some activity in order to develop or maintain physical fitness and overall health. Frequent and regular physical exercise is an important component in the prevention of some of the diseases of affluence such as cancer, heart disease, cardiovascular disease, Type 2 diabetes and obesity.

Exercises are generally grouped into three types depending on the overall effect they have on the human body:


 * Flexibility exercises such as stretching improve the range of motion of muscles and joints.
 * Aerobic exercises such as walking and running focus on increasing cardiovascular endurance.
 * Anaerobic exercises such as weight training or sprinting increase short-term muscle strength.

Physical exercise is extremely important for maintaining physical fitness including healthy weight; building and maintaining healthy bones, muscles, and joints; promoting physiological well-being; reducing surgical risks; and strengthening the immune system.

Proper nutrition is as important to health as exercise. When exercising it becomes even more important to have good diet to ensure the body has the correct ratio of macronutrients whilst providing ample micronutrients, this is to aid the body with the recovery process following strenuous exercise.

Proper rest and recovery is also as important to health as exercise, otherwise the body exists in a permanently injured state and will not improve or adapt adequately to the exercise.

The above two factors can be compromised by psychological compulsions (eating disorders such as exercise bulimia, anorexia, and other bulimias), misinformation, a lack of organization, or a lack of motivation. These all lead to a decreased state of health.

It should be noted that Delayed Onset Muscle Soreness can occur after any kind of exercise, particularly if the body is in an unconditioned state relative to that exercise.

Exercise benefits
Frequent and regular exercise has been shown to help prevent or to cure major illnesses such as high blood pressure, obesity, heart disease, Type 2 diabetes, insomnia, cancer and depression, and many more diseases. Researchers have shown that three 10 minute walks burn as many calories and exercise your heart as well as one 30 minute walk. Exercise can also increase energy and raise your threshold for pain. There is conflicting evidence as to whether vigorous exercise (more than 70% of VO2 max) is more or less beneficial than moderate exercise (40 to 70% of VO2 max). However studies have shown that vigorous exercise executed by healthy individuals can effectively increase opioid peptides (aka endorphins, a naturally occurring opiate that in conjunction with other neurotransmitters is responsible for exercise induced euphoria), positively influence hormone production (i.e., increase testosterone and growth hormone), and help prevent neuromuscular diseases. Some of these benefits can be realized by moderate exercise but to a much lesser degree.

Common myths
Many common myths have arisen surrounding exercise, some of which have a basis in reality, and some which are completely false.

Spot reduction
It is a common belief that training a particular body part will preferentially shed the fat on that part; for example, that doing sit-ups is the most direct way to reduce subcutaneous belly fat. This is false: you cannot reduce fat from one area of the body to the exclusion of others. Most of the energy derived from fat gets to the muscle through the bloodstream and reduces stored fat in the entire body. Sit-ups may improve the size and shape of abdominal muscles but will not specifically target belly fat loss. Instead, such exercise may help reduce overall body fat, affecting all parts of the body as determined by genetics. In fact, belly fat will often be the last fat removed from the body.

Physician consultation
It is recommended that a physician be consulted before beginning an exercise program. Despite a common belief that only overweight people need a physical before beginning an exercise program, apparently healthy people can still have unknown medical conditions, such as a heart murmur, that can cause severe injury or death not only to themselves, but also to others that are dependent upon them, such as someone they are spotting.

Muscle and fat tissue
Some people incorrectly believe that muscle tissue will turn into fat once a person stops exercising. In reality, fat tissue and muscle tissue are fundamentally different. However, the more common expression of this myth "muscle will turn to fat" has a grain of truth. Although a muscle cell will not become a fat cell, the material that makes up muscle can in fact turn to fat. The catabolism of muscle fibers releases protein, which can be converted to glucose that can be burned as fuel, and excesses of which can be stored as fat. Moreover, the composition of a body part can change toward less muscle and more fat, so that a cross-section of the upper-arm for example, will have a greater area corresponding to fat and a smaller area corresponding to muscle. This is not muscle "turning to fat" however, it is simply a combination of muscle atrophy and increased fat storage in a given body part.

Abdominal muscles
Abdominal muscles are like any other muscle tissue; they don’t necessarily respond to hundreds of repetitions. If an individual can easily do 15 reps of any ab exercise, they should consider switching exercises or adding resistance. Abdominal muscles can be over-trained like any other muscle. It is important that abdominal muscles have enough rest to recover from a bout of exercise. Over-training will result in diminished gains. Futhermore, men and women all have the same anatomy that responds the same way to exercise. Men and women must follow the same rules regarding diet, exercise and life-style to achieve esthetic and health related goals.

Too much exercise
Too much exercise can be harmful. The body needs sufficient rest, which is why most health experts say one should exercise every other day or 3 times a week. Without proper rest, the chance of stroke or other circulation problems increases, and muscle tissue may develop slowly.

Over-exercising does more harm than good. For many activities, especially running, there are also significant injuries that occur with poorly regimented exercise schedules. In extreme instances, over-exercising induces serious performance loss. Unaccustomed overexertion of muscles leads to rhabdomyolysis (damage to muscle) most often seen in new army recruits.

Stopping excessive exercise suddenly can also create a change in mood. Feelings of depression and agitation can occur when withdrawal from the natural endorphins produced by exercise occurs.

Excess is unhealthy. Exercise should be controlled by each body's inherent limitations. While one set of joints and muscles may have the tolerance to withstand mutiple marathons, another body may be damaged by 20 minutes of light jogging. This must be determined by each exerciser.

Exercise helps brain function
In the long-term, exercise helps the brain by:
 * increasing the blood and oxygen flow to the brain
 * increasing growth factors that help create new nerve cells
 * increasing chemicals in the brain that help cognition

Categories of physical exercise
Some activities can fall into more than one category of exercise. For instance: cycling can be used for endurance or high-intensity interval training; weightlifting is resistance training and can be high-density exercise with certain workout designs.

Sometimes the terms 'dynamic' and 'static' are used. 'Dynamic' exercises such as steady running, tend to produce a lowering of the diastolic blood pressure during exercise, due to the improved blood flow. Conversely, static exercise (such as weight-lifting) can cause the systolic pressure to rise significantly.

Breathing
Active exhalation during physical exercise helps the body to increase its maximum lung capacity, and oxygen uptake. This results in greater cardiac efficiency, since the heart has to do less work to oxygenate the muscles, and there is also increased muscular efficiency through greater blood flow. Consciously breathing deeply during aerobic exercise helps this development of the heart lung efficiency.