The summer months are almost upon us and as children and adults head to swimming pools, lakes and the ocean, officials with the U.S. Centers for Disease Control and Prevention are warning of the dangers of underwater breath-holding games and exercises.

Underwater breath-holding games can be fatal to swimmers, according to the CDC. (JaySi, ThinkStock)

According to a new report from the CDC, dangerous underwater breath-holding behaviors can lead to otherwise strong, healthy swimmers losing consciousness underwater and drowning. Breath-holding contests are a common cause, but training drills for swimmers aimed at improving their lung capacity can also cause accidental drowning.

"Holding your breath underwater, challenging others and making a game of it is not safe.  It's also not safe when coaches give sets that require swimmers to stay underwater for specific periods of time. Coaches need to know the limits," said Tom Gill, spokesperson for the United States Lifesaving Association. "When people go under water and hold their breath for too long, carbon dioxide builds up and forces them to pass out under the water.  At that point, they can't do anything to save themselves and get themselves above the water to a safe location."

"Breath-holding for a few seconds at a time is one thing, but there is always that one who tries to push the limit," Gill said. "The key is that in any swimming situation, there should be constant supervision and no one should swim alone. If parents take their children to the pool, they shouldn't only rely on lifeguards.  They should be there watching as well."

It is also important for swim coaches to be aware of the issue and to not push a child beyond a reasonable level when underwater.

"Parents aren't always there when their children are at swim practice. They should just make sure that their child's coach is exercising the children safely," Gill said.