Swimming for fun, exercise, and competition is popular among people of all ages and physical conditions.

A mother and daughter use a kickboard to help the young girl learn how to swim.

A mother and daughter use a kickboard to help the young girl learn how to swim. Swimming is an excellent aerobic exercise that prevents impact on and straining of muscles, bones, and joints, while the resistance of the water forces the muscles to work hard, building strength.



Born June 30, 1985, in Baltimore, Maryland, Michael Phelps, is the youngest man to break a swimming world record. Phelps took to swimming when he was seven years old, finding that some of his normal awkwardness, caused by being hyperflexible, vanished in the water. At 11, Phelps began training with Bob Bowman, who saw immediately that Phelps had Olympic potential. Bowman encouraged Phelps to train to a degree where he could watch the 2000 Olympics, but Phelps pushed himself harder. At 15, Phelps placed in the Olympic trials and became the youngest member of the American team for the Sydney Olympics. Then at 16, Phelps became the youngest American male swimmer to become a professional.


(Leonard Zhukovsky/ Shutterstock.com )

In the 2004 Olympic trials, Phelps became the first swimmer to qualify in six individual Olympic events. Given the intensity of the scheduling, Phelps chose to participate in only five events, racing 17 different times, creating the opportunity for him to challenge Mark Spitz's record of seven gold medals in one Olympics. At his first event, the results were promising: Phelps won the 400-meter individual medley by a full 3.5 seconds, setting a world record. But breaking the gold-medal record at the 2004 Olympics was not to be. The American team placed third in the 4x100 freestyle relay, and Phelps took a bronze in the 200-meter freestyle, losing to Australian Ian Thorpe, who had beaten him in the 100-meter butterfly at the 2003 World Championships. When Bowman took the head coach position for the University of Michigan's swimming team after the 2004 Olympics, Phelps went with him, enrolling for classes and continuing to train with him in Ann Arbor. Due to his status as a professional, he was unable to race for the university, and instead served as a volunteer assistant coach under Bowman. Phelps continued to train all 365 days of the year—including Christmas morning— typically swimming between 7 and 12 miles per day.

At the 2008 Games in Beijing, Phelps raced 17 times in nine days, taking the gold medal in all eight of the events he raced and succeeding in his goal of breaking Spitz's record as well as tying the record of gymnast Aleksander Dityatin for eight medals at a single Olympics. The games brought Phelps's career totals of world records to four individual world records and two team world records. In 2012, at the London games, he won four more gold medals; six medals in total, and in 2016 in Rio, he won another five gold medals and a silver in the 100m butterfly.

To enhance the visibility of swimming, Phelps founded a social networking site, SwimRoom.com, and is the founder of the Michael Phelps Foundation that promotes health and activity, primarily for children, through the sport of swimming.


Swimming is the second most popular exercise activity and the third most popular sport among Americans. There are nearly nine million residential and public-use swimming pools in the United States:


Swimming is the most popular exercise activity of American children:


Humans have been swimming throughout recorded history. Swimming associations, clubs, and competitions appeared in the nineteenth century. In the twenty-first century most towns in the United States have public pools and many have indoor pools for year-round swimming.


Swimming is low-impact, non-weight-bearing exercise that can be enjoyed by the entire family and continued throughout life. U.S. Masters Swimming has competitions for all age groups, including those aged 100–104. People can swim in pools, ponds, rivers, lakes, and oceans. Most public pools, fitness centers, and private clubs offer swimming lessons.

The crawl, also called freestyle, is the most popular swimming stroke and the easiest to learn. Breaststroke and butterfly are less popular since they are more difficult and require precise timing. The butterfly also requires strength.

Adapted aquatics modifies swimming techniques to accommodate individual abilities. People with almost any physical disability can exercise by swimming with an appropriate flotation device. Flotation devices also are used for learning to swim, practicing specific strokes, and adding resistance for building muscle strength and tone. These devices include:


A general exercise program that strengthens the shoulder and upper back muscles can help prevent shoulder pain from the repetitive motion of swimming. Swimming should be preceded by a three- to five-minute warm-up of jumping jacks, stationary biking, or walking or running in place, followed by slow and gentle stretching, holding each stretch for 30 seconds.


No special equipment is needed for swimming. Optional equipment includes bathing caps to keep hair dry, goggles for eye protection, and swim fins to increase motion in the water. Face masks and snorkels are often used when swimming in lakes or oceans to view underwater aquatic life.

Swimmers should dry off or shower immediately after swimming, so a towel or place to shower is beneficial.

Training and conditioning

Swimming may be a relatively high-intensity activity and lap swimming or swimming fast can be very vigorous exercise. Swimming for cardiovascular fitness should raise the heart rate to its target level for at least 20 minutes. Workout schedules for improving cardiorespiratory endurance recommend at least 20–30 minutes of swimming three to five days per week. Interval training involves swimming 50 yards followed by a 10-second rest, then swimming 100 yards and resting 10 seconds, and so on up to 300 yards of swimming, and then reversing the pattern. Varying strokes can help prevent boredom. An after-swim cool-down can involve slowing down the stroke or switching to a more leisurely stroke. Water that is warmer than body temperature relaxes muscles, whereas cooler water prevents overheating during a strenuous workout.

Swimming may also be enjoyed for leisure and fun with family and friends, whether at the beach or in a pool. Many people choose to enjoy a calm and restful swim as a means of relaxation after work or a stressful day.


Since water cushions the joints, it greatly reduces the incidence of athletic injury. Nevertheless, according to the U.S. Consumer Product Safety Commission, there were almost 172,000 swimming-related injuries treated in emergency rooms, physicians' offices, and clinics in 2007. The most common swimming injury is shoulder pain from repetitive motion. Other swimming risks include:

Two of the biggest swimming dangers are panicking and becoming too tired to swim. Jumping into cold water can raise blood pressure and heart rate and slow down muscles. Swimmers should:

Ocean swimming requires special precautions, including:

Various measures can make swimming more pleasurable:

Swimmer's ear or otitis externa, an infection of the outer and/or inner ear canal often caused by Pseudo-monas aeruginosa, may be prevented by:

Strenuous physical exercise that results in a significant increase in respiration and heart rate.
A unit of energy supplied by food.
A diarrheal disease caused by a protozoa and contracted by swallowing water contaminated with sewage or human or animal feces.
Personal flotation device (PFD)—
A device such as lifejacket or belt that is designed to keep people afloat with their nose and mouth above the water.
Recreational water illness (RWI)—
Illnesses that are spread by swallowing, breathing, or contacting contaminated water from pools, lakes, rivers, or oceans; diarrhea is the most common RWI.
The muscle of the back of the arm.

Precautions for preventing RWIs include:


Drowning is the second most common cause of death from unintentional injury among children and teens:

The American Academy of Pediatrics (AAP) suggests that children be taught to swim between the ages of five and eight and cautions that children younger than four may not be developmentally ready to learn to swim. However, a recent study suggests that swimming lessons may help prevent drowning in one to four-year-olds. In addition:


Many people swim as one component of a weightloss program. Swimming can also speed up metabolism that may contribute to weight loss. The number of calories burned by swimming depends on stroke efficiency and buoyancy:

There are numerous health benefits associated with swimming. Swimming at a comfortable pace is a good way for a sedentary person to begin exercising because it is less strenuous than many other types of exercise and increases one's fitness without causing strain.

Swimming helps to improve cardiovascular fitness, breathing, the heart muscle, and circulation. The rhythmic motion of swim strokes promotes controlled, deep breathing, utilizing the diaphragm, and increases lung volume. The heart is strengthened and increases its efficiency. People with hypertension benefit from swimming because the blood vessels expand and increase blood volume, which can lower blood pressure. Circulation in general improves because water pressure on the legs and feet moves blood upward through the veins.


Endurance, muscle strength, joint flexibility, and balance are enhanced with swimming. Almost all the major muscle groups, especially the arm, shoulder, and chest muscles, are used during the exercise. Men who completed an eight-week swimming program had a 23.8% increase in triceps strength.

Studies have shown that many chronic illnesses can be decreased with 150 minutes of swimming each week. Swimming can also reduce risk of death by about onehalf compared to sedentary people. It is a beneficial form of exercise for people with heart disease and diabetes and can maintain or improve bone density in post-menopausal women. The intensity and frequency of migraine headaches has also been shown to decrease with swimming. Older adults may shown a decrease in disability and improved quality of life. It can even improve the physical and mental health of pregnant women and the health of their unborn babies.

Mental health benefits of swimming include improving mood in both women and men and providing an opportunity for quiet contemplation. Children with developmental disabilities often find swimming very therapeutic as well.

Swimming has been found to increase sustained cardiorespiratory endurance—the delivery of oxygen and nutrients to tissues and removal of waste products. Twelve weeks of swim training improved maximal oxygen consumption by 10% in a group of sedentary middle-aged men and women. It increased their stroke volume—the amount of blood pumped per beat, a measure of heart strength—by up to 18%.

See also Prenatal exercise ; Sunburn .



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Jendrick, Megan Quann, and Nathan Jendrick. Get Wet, Get Fit: A Complete Guide to a Swimmer's Body. New York: Fireside, 2008.

Montgomery, Jim, and Mo Chambers. Mastering Swimming. Champaign, IL: Human Kinetics, 2009.

Salo, Dale, and Scott A. Riewald. Complete Conditioning for Swimming. Champaign, IL: Human Kinetics, 2008.


“A Sport for All Seasons.” Harvard Health Letter 35, no. 1 (November 2009): 4.

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Peterson, Judy. “Get in the Swim!” Current Health 2 52, no. 4A (July/August 2009): 18.

Redford, Gabrielle DeGroot. “Lap It Up.” AARP The Magazine 35, no. 8 (April/May 2009): 8–11.


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“Swimming Injury Prevention.” OrthoInfo. August 2016. http://orthoinfo.aaos.org/topic.cfm?topic=A00116 (accessed January 19, 2017).

“Water Safety.” KidsHealth. June 2014. http://kidshealth.org/en/parents/water-safety.html?WT.ac=ctg# (accessed January 19, 2017).

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Arthritis Foundation, 1355 Peachtree St. NE, Ste. 600, Atlanta, GA, 30309, (404) 872-7100, (844) 571-4357, http://www.arthritis.org .

American Academy of Orthopaedic Surgeons, 9400 W Higgins Rd., Rosemont, IL, 60018, (847) 823-7186, (800) 626-6726, Fax: (847) 823-8125, customerservice@aaos.org, http://www.aaos.org .

American Academy of Pediatrics, 141 Northwest Point Blvd., Elk Grove Village, IL, 60007-1098, (874) 434-4000, Fax: (874) 434-8000, http://www.aap.org .

Centers for Disease Control and Prevention, 1600 Clifton Rd., Atlanta, GA, 30333, (800) CDC-INFO (232-4636), cdcinfo@cdc.gov, http://www.cdc.gov .

U.S. Masters Swimming, 1751 Mound St., Ste. 201, Sarasota, FL, 34236, (800) 550-SWIM, Fax: (941) 556-SWIM, http://www.usms.org .

USA Swimming, 1 Olympic Plaza, Colorado Springs, CO, 80909, (719) 866-4578, Fax: (719) 866-4669, http://www.usaswimming.org .

Margaret Alic, PhD
Revised by Laura Jean Cataldo, RN, EdD

  This information is not a tool for self-diagnosis or a substitute for professional care.