Attention instructors out there teaching diver’s over 40! Here’s a study you showed be aware of:
Underwater Scan Finds Significant Heart Changes in Divers
Test May Identify Undetected Abnormalities That Might Prove Fatal in a Dive
An underwater ultrasound scan of scuba divers’ hearts found significant changes
in cardiac function during and after a dive, according to a study.
An underwater ultrasound scan of scuba divers’ hearts found significant changes
in cardiac function during and after a dive, according to a small study in the
journal Acta Physiologica. The test could be used to identify novice scuba divers
with undetected heart disease or cardiac abnormalities that might prove fatal
during a dive, researchers said.
Scuba diving is growing in popularity among older Americans and heart attacks
and unknown heart rhythms are the most common cause of diving-related deaths
after age 40, according to the Divers Alert Network, a nonprofit research group.
The study, conducted in Italy, involved 18 scuba divers, including 16 men and
two women. The participants were about 42 years old and each had made at least
100 dives. None smoked or had hypertension, heart or lung disease.
Cardiac-ultrasound tests were conducted on land before and after diving, and
underwater at two depths. The divers wore suits with access for an ultrasound
probe and maintained a kneeling position for 10 minutes at a depth of about
33 feet, then five minutes at 16.4 feet.
Among the heart changes recorded during and after the dive: The volume of the
left ventricle, a lower heart chamber that pumps newly oxygenated blood to the
body, increased significantly, while the flow of blood into the ventricles
decreased. These changes may be due to a diving-related shift of blood from
the lower extremities to the upper body, exerting a constrictive effect on
the chest, the researchers said.
Bradycardia, the term for a slow resting heart rate, a condition that can
cause dizziness and weakness if the rate falls below 50 beats per minute,
was documented after but not during the scuba diving. The cardiovascular
changes that occur during immersion may increase the risk of cardiac problems
in divers who are unfit, overweight or have underlying heart disease,
researchers said.
Caveat: Heart rate may have been higher underwater because divers were
disturbed or stressed by the ultrasound tests, researchers said. |