Health beat: The benefits of aquatic exercise

Published 3:12 pm Monday, July 26, 2021

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Summer is here and so are the hot temperatures that accompany it. In eastern North Carolina, we often encounter environmental conditions that make exercising outdoors in the summer a challenge.

Extreme heat and humidity can become barriers that prevent individuals from maintaining recommended activity levels. One way people can beat summer’s heat is cooling off in a body of water or pool. Fortunately, the many benefits of aquatic exercise provide a solution to staying consistent with exercise during the summer and even year round.

The properties of water allow unique opportunities to aid or resist our motion. When standing still on land under normal conditions, the primary force our bodies encounter is the downward pull of gravity. For certain populations, gravity’s pull leads to joint compression and pain which shortens the amount of time they can exercise or prevents it altogether. When immersed in water, an upward force we call buoyancy counters the effects of gravity. The amount of buoyancy’s force is equal to the weight of fluid displaced by the submerged body. This explains why you feel lighter and lighter as more of your body is submerged in water.

When standing in waist-deep water, individuals bear roughly 50% of their body weight. A move to chest-deep water decreases the amount of weight individuals bear to roughly 25-30% and can be lower than 10% in neck-deep water. Buoyancy greatly benefits obese individuals or those suffering from degenerative joint disease by reducing load and impact pressure. While buoyancy can make exercising easier if used for that purpose, it can also enhance the intensity of a workout. By using buoyant equipment such as aquatic dumbbells or pool noodles, an individual can work against the upward force of buoyancy to challenge various muscle groups.

Exercise in water can also reduce swelling due to the effects of hydrostatic pressure. When immersed in water, a pressure is exerted on all surfaces of the submerged body. If an individual is vertical in water, this pressure aids the return of blood through our veins to our hearts.

This is beneficial to those with swelling in the lower extremities as it can limit the pooling of blood in the lower legs and feet. Similar to buoyancy, the effects of hydrostatic pressure can be used to make exercise easier or more difficult. When the chest is submerged in water, hydrostatic pressure challenges the muscles used to inhale deeply and forcefully. By increasing the muscular effort required to expand the chest when inhaling, water trains and improves aerobic conditioning.

Another property of water that alters motion is viscosity. Water is more viscous than air, which means water molecules will stick to a submerged body more than air molecules in normal conditions. The adhesion of water molecules to the body causes drag, or the resistance felt when moving in water. Greater muscular effort is required to overcome the additional resistance to movement. This leads to increases in perceived exertion after exercising in water. Walking in water is similar to walking against a strong wind that gusts constantly. On land under normal conditions, once a constant speed is achieved the muscle load decreases. This is not the case in aquatic exercise where drag forces a constant muscle load throughout each range of motion.

If you are finding it tough to get outdoors and stay active, take advantage of the water and its many benefits for exercise. For select populations, the properties of water allow an opportunity to move in ways that may be too painful on land. For all populations, aquatic exercise can provide a healthy and fun way to beat summer’s heat!

Travis Rogerson is the  exercise programming supervisor at Vidant Wellness Center in Washington.