What Happens to the Body During Exercise?

Exercise provides numerous benefits to your body and mind. A good workout routine can help you lose weight, gain muscle, build endurance and give you a healthy outlook on life as you set goals and maintain an active lifestyle. Many physiological changes take place in your body when you exercise.


Muscle Activation

As your brain sends voluntary messages for your muscles to flex, extend and hold through your exercise routine, the movement creates body heat and expends energy. This energy is stored throughout the body in adenine nucleotide bonds called ATP. The process of breaking these bonds releases potential energy in the muscles so you can keep moving. Metabolic waste is then released from the cells of the muscles into the bloodstream, later to be excreted through your liver and kidneys and through sweat from your skin pores. As the muscles consume oxygen, the blood vessels in your muscles have to tighten to call for more. This triggers the heart to pump harder and stronger.

Heart Pumping

The heart is responsible for distributing oxygen and nutrients to the muscles. The stronger the heart pumps, the more oxygen and nutrients come to the muscles and the more waste is released. During exercise, the heart can expand and contract to accommodate more blood flow, and like any muscle, it becomes stronger through regular, routine activity. Anyone diagnosed with heart disease should consult a doctor before adopting an exercise program, but light to moderate exercise, such as walking and low-impact resistance training, is a good way to build strength in your heart. The American Heart Association states that exercising for as little as 30 minutes a day can reduce the risk of heart disease. A stronger heart will improve your circulation, reduce inflammation in the arteries and keep the blood vessels flexible by preventing the buildup of waste in the bloodstream.

Lung Function

The lungs procure the oxygen necessary to feed your muscles energy. As your muscles work and your heart pumps harder, your breathing rate increases to meet your body's need for oxygen. It is in your lungs that the dark blue, oxygen-deficient blood cells trade carbon dioxide for oxygen between the capillaries and the alveoli of the lungs. Improving cardiorespiratory function through exercise means that the body will be able to efficiently distribute and consume oxygen for future workouts, as well as for day-to-day activities.

Hormone Boost

Exercise has a direct effect on the glands of the body that produce hormones. Some of the glands affected are the thyroid and the adrenal glands and the kidneys, all of which benefit from the increased activity and fresh oxygen circulating in the body due to exercise. Perhaps the most important gland affected by exercise is the pituitary gland. When stimulated, the pituitary releases the human growth hormone (HGH) that initiates the regeneration of bones, muscles and connective tissues throughout your body. The best way to keep your body producing HGH is to stimulate the pituitary gland to produce the hormone through regular exercise.

Endorphin Kick

When your body experiences the painful sensation of lactic acid building up in the muscles from a lack of oxygen, the brain produces polypeptide molecules called endorphins that bind the neural receptors capable of sensing that pain. This analgesic effect reaches a high when your body switches from using oxygen present in the muscles to using oxygen outside the body to make new energy. Known as a "runner's high," the numbing effect of endorphins during exercise can become a healthy addiction, creating a sense of well-being after exercise and making you want to come back for more.


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This article reflects the views of the writer and does not necessarily reflect the views of Jillian Michaels or JillianMichaels.com.