Physical exercise is the performance of some activity in order to develop or maintain physical fitness and overall health. It is often directed toward also honing athletic ability or skill. Frequent and regular physical exercise is an important component in the prevention of some of the diseases of affluene such as 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, functional training or sprinting increase short-term muscle strength.
Physical exercise is considered 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 at least 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. Hence, it is important to remember not to do the same type of exercise two-days-in-a-row.
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.
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== yoyoyoyoyoyoyoyoyoyoyoyoyoyoyoyoyoyo 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, and depression. Researchers have shown that three 10 minute walks burn as many calories and exercise the heart as well as one 30 minute walk. (Strength training, on the other hand, appears to have continuous energy-burning effects that persist for about 24 hours after the training.) Exercise can also increase energy and raise one's 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 and has been shown to be addictive), positively influence hormone production (i.e., increase testosterone and growth hormone), and help prevent neuromuscular diseases. These benefits are not as fully realized with more moderate exercise.
Both aerobic and anaerobic exercise also work to increase the mechanical efficiency of the heart by increasing cardiac volume, or myocardial thickness.
Many myths have arisen surrounding exercise, some of which have a basis in reality, and some which are completely false. Myths include:
That excessive exercise can cause immediate death. Death by exercise has some small basis in fact. Water intoxication can result from prolific sweating (producing electrolyte losses) combined with consumption of large amounts of water (e.g. when running a marathon).
Weightlifting makes you short or stops growth. One caveat is that heavy weight training in adolescents can damage the epiphyseal plate of long bones.
Targeted fat 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: one 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 for 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
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 different tissues of the same body part. Another element of increased fatty deposits is that of diet, as most trainees will not significantly reduce their diet in order to compensate for the lack of exercise/activity.
Too much exercise
Too much exercise can be harmful. The body part needs at least a day of 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.
Appropriate exercise does more good than harm, with the definition of "appropriate" varying according to the individual. For many activities, especially running, there are 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. Another danger is overtraining in which the intensity or volume of training exceeds the body's capacity to recover between bouts.
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.
Physical exercise releases opioid peptides or endorphins, opiates that exhibit synergetic effects with other neurotransmitters, causing exercise euphoria, also known as "runners high", and causing addiction to physical exercise and possibly decreased sex drive. This usually leads to over-exercising; a person suffering exercise addiction is often described as a "gym rat", "body nazi", "exercise freak", etc.
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