Pressure And Heart Conditions

[boomx5]

It seems like I've read alot about people dying from heart attacks while diving. My question is apart from the physical exertion from diving, could pressure alone cause stress on the heart that could lead to a heart attack?

 

[BillP]

Howdy boomx5:

Good question, and the answer is a qualified, "yes".

Diving puts a lot of stresses on the heart. The primary stresses are generally felt to be due to the physical exertion of diving with lifting heavy gear, swimming (sometimes vigorously), climbing ladders, etc. Immersion in water and being cold trigger reflexes that can affect the heart. The weightless environment of diving causes fluid shifts in the body from the periphery to the heart and lungs giving the heart a little extra work to do. There is also the emotional stress of diving with worry, fear, and/or excitement perhaps leading to an "adrenaline rush".

But just breathing oxygen at increased partial pressures (or maybe even just being at increased pressure without increased partial pressure of oxygen- that part is less clear) seems to stimulate a part of a diver's nervous system called the "parasympathetic" nervous system that helps regulate the cardiovascualar system. Being in a hyperbaric environment (even a dry chamber) has been shown to slow the heart and sometimes even lead to some irregular heartbeats. It is very unlikey that these changes would be noticed by a healthy diver, and they probably take a backseat to the other concerns in the above paragraph in divers with heart disease, but it could be a factor.

HTH,

Bill