Women and older sea swimmers are more likely to suffer from a condition called pulmonary oedema which causes fluid on the lungs, according to authors of a new study, which revealed that the condition has been reported in 1 to 2% of open-water swimmers.
The report details risk factors including older age, swimming long distances, cold water, being a woman, high blood pressure and pre-existing heart disease. They say it can also occur in those who are otherwise fit and healthy.
Swimming-induced pulmonary oedema (SIPE for short ) leaves swimmers struggling to draw breath and depletes their blood of vital oxygen. Doctors are unclear as to exactly what causes SIPE.
Dr Bob Rutherford, Galway-based Respiratory Physician, has never seen a case of swimming-induced pulmonary oedema, but he knows the risks.
“It’s not that common, however I know that some people can get it recurrently. While we don’t know exactly what causes it, when we’re swimming, our body is flat and each part of our bodies are equally exposed to gravity.
“So more blood is returning to the heart than when you’re walking or jogging or cycling. There are certain risk factors too of course.
“If you are over 50, or if you have had anything wrong with your heart at all, they are risk factors. It is generally more common in women too, which we are unsure of as to why. It could be that women are generally smaller than men, so a proportionately higher volume of blood is returned to the heart quicker than in men.”
What you wear in the water can also have an impact, Dr Rutherford said.
“Tight wet suits will make it worse, as they will constrict the blood vessels, and blood vessels are constricted anyway in the cold water.”
Does length of time in the water make a difference?
“Yes, absolutely. If you’re doing more than a dip, if you’re doing a proper swim, you’re generally only breathing every four strokes. You also tend to take bigger breaths in than a jogger, let’s say. That could contribute to it as well,” says Dr Rutherford.
Moving on, what other (generally uncommon ) conditions can be caused by sea swimming?
Dr Rutherford mentions Transient Global Amnesia, which is known to be triggered by cold water immersion. It happens to about 1 in 10,000 people, and the main risk factor is a history of migraines.
“What can happen to someone experiencing Transient Global Amnesia is the blood vessels in their head can suddenly sort of spasm and they lose their memory for three or four hours afterwards. Then they’re back to normal, and they don’t tend to get it again. We could see about one case a week come into casualty during the summer.”
Dr Rutherford describes an even more unusual condition that has been documented — cases in which people can experience delirium while watching the waves. “It’s bizarre, but people can experience some sort of hypnotism while they’re watching waves, it can send them into a strange state. I’ve never seen a case of it, but there have been cases that have come in to casualty.”
While exercising in water is said to be beneficial for people with Parkinson’s, they should also be mindful of the risks while swimming in the sea and open cold water. Dr Rutherford mentions a survey that showed 49% of people who developed Parkinson’s had a near-drowning experience after developing the disease. “People with Parkinson’s can’t swim as fast as other people, and also their leg and arm movements are not as coordinated.”
While it is very important to be aware of these potential conditions, it is also just as important to put them into context and not lose sight of the endless benefits a dip in the sea can provide.
Sea water, which is rich in magnesium, can help to treat skin conditions like psoriasis and eczema. It can also help to lower cortisol and calm your nervous system. Indeed the act of plunging into cold water and focusing on your breath can mirror meditation, as there is not much room left in your head for focusing on much else during those few minutes.
Do not lose sight of what the sea can offer you, but be smart and respect its power.