SWIMMING IS GREAT, BUT... - with MUDr. Martin Záhorec, PhD.

It's been a week since we came to our usual summer destination. True to her pattern of needing between five to seven days to adjust, our "blue kid" made peace with the Adriatic Sea being colder than her bath.

Swimming is a great activity for Fontan patients. It is a type of sport with positive effects on cardiorespiratory function and health. During swimming, by laying down in the water, in theory, the passive venous return to the lungs is easier than against the gravity during running around.
(MUDr. Martin Záhorec, PhD., pediatric cardiologist, Bratislava, Slovakia)

Vedenie kardiocentra

NÚSCH, a.s.Embex - www.embex.sk

So, this year, on top of our daily family beach time, we enrolled her in a morning kids' swimming school. While in general, I tend to let her set her own limits, I have to admit that these days I am struggling with letting go of my parental control.

Clean breathing

She has a new snorkeling set and a whole range of other stuff she loads me with when we are hitting the beach. I see her a lot below the surface - jumping, snorkeling, diving, playing... Sometimes it seems as if she is testing her limits. So, more than I'd like, I catch myself making her take a rest, to breathe, to warm up.

But, the thing that made me dive into research was - snorkel and the importance of "clean breathing" (as I named it).

As a scuba diver myself, I know that it is not a sport for anyone less than fit. I grieved and then let go of the idea that my daughter will ever go to a big fish dive with me. But I haven't given up looking into what she can do. And I want to let her do it as much as she feels she can.

Any LONGER BREATH-HOLDING activity is not very advisable for Fontans. They are more vulnerable even to mild changes of resistance in pulmonary flow, since there is no ventricle - a pump to balance it. Although the data are sparse, and we lack evidence about it, in theory, with holding breath, our Fontan kids may end up with increased pulmonary artery pressure and less passive blood flow through the lungs. That will make them feel more tired and more out of breath. Ultimately, there will be less oxygen delivered to their organs. Having said that, let them try it under close parental observation. But just for fun, not rigorously - not too much and too regularly. Rather swim regularly then dive regularly.
(MUDr. Martin Záhorec, PhD., pediatric cardiologist, Bratislava, Slovakia)

One thing that helps is - snorkel. Children can keep breathing, while enjoying the underwater world.

Being cold vs. hypothermia

By solving a snorkel challenge, I burdened myself with another one - when (and how) to get her out of the water. She persists convincing me she is not cold, and does not need rest, even though her lips turn purple, her forehead and nose change to a certain shade of grey, and a deep blue paints her fingers. On top of her changing colours with the speed a mature chameleon would envy, her body tends to shiver and her teeth chatter.

In colder water, peripheral vessels in the body constrict which increases the workload on the single ventricle. However, a forced interruption of a child's activity is psychologically harmful and there is no evidence of long term physical benefit. Swimming is different from diving. Both continuous breathing and a horizontal position make a difference.
(MUDr. Martin Záhorec, PhD., pediatric cardiologist, Bratislava, Slovakia)

So, a child with a single ventricle heart (and a Fontan circulation) will get cold quicker, and tired easier. And if making a child get out of the water to rest, dry and warm up might do more harm than good... when to sound an alarm.

People with a single ventricle may be more at risk to develop hypothermia because of their impaired thermoregulation and circulation. But, before a thermometer becomes a permanent part of the beach bag, it is worth emphasizing that there is a clear, instinctive and tangible difference between being cold and having hypothermia.

What we do know is that shivering is a sign of getting cold, while violent shivering and shaking which you cannot stop – in or out of water – is a symptom of moderate hypothermia.
(Outdoor Swimming Society)

Bottom line, developing hypothermia is actually not so easy. If a child does not plan to swim accross the English Channel or dip into an ice cold water, it is safe to conclude that summer holiday activities are safe. And advisable.

Physical activity is important for children with congenital heart defects (CHD), not only for somatic health, but also for neurologic, emotional, and psychosocial development. (...) one in five patients with complex CHD are non-swimmers, a situation that is concerning in regard to motoric development, inclusion and integration, as well as prevention of drowning accidents.
(Apitz, C.; Tobias, D.; Helm, P.; Bauer, U.M.; Niessner, C.; Siaplaouras, J. Nationwide Survey Reveals High Prevalence of Non-Swimmers among Children with Congenital Heart Defects. Children 2023, 10, 988.)
Nationwide_Survey_Reveals_High_Prevalence_of_Non-S.pdf