Unveiling SIPE: Your Essential Guide to Cold Water Swimming Adventures!

When considering the possible adverse effects of swimming in chilly water, our initial thoughts frequently revolve around cold water shock, hypothermia, or hazardous aquatic conditions. However, another swimming-related hazard to recognize is SIPE – swimming-induced pulmonary edema.

Though SIPE remains a relatively uncommon incident, the rise in individuals engaging in open water swimming and the trend towards year-round outdoor swimming has led research from the National Institutes of Health to indicate a growing number of cases. We will explore what SIPE entails, its indicators and risk factors, and the appropriate actions to take if you or a training partner displays symptoms. This way, you can safely embrace all the advantages of your cold water swims.

What is SIPE?

SIPE signifies swimming-induced pulmonary edema. It is an uncommon yet potentially grave condition affecting the respiratory system, which results in sudden and intense breathlessness that is disproportionate to perceived effort levels either while swimming or immediately afterward, often in otherwise healthy individuals. This severe breathlessness may also be accompanied by coughing up blood-streaked sputum (frothy fluid) and a sensation of constriction in the chest.

Although the exact origin of SIPE is unclear, studies imply it is linked to a rapid increase in blood pressure resulting from strenuous exertion while submerged in water. An examination of SIPE published by the American College of Cardiology clarifies that immersion in water places compressive pressures on the body, heightening pressure on blood vessels. This can be further aggravated by snugly-fitting wetsuits. Such pressure leads to a redistribution of blood volume to the thoracic cavity (i.e., the chest area) and elevates blood pressure. In particular, cold water immersion has been discovered to further boost blood pressure.

It is believed that this escalation in pulmonary vascular pressure can result in microscopic ruptures in the barriers of the alveoli – the minute blood vessels located in the lungs – prompting blood to ‘leak’ from the vessels into the lungs, resulting in fluid accumulation.

Why is SIPE dangerous?

Symptoms of SIPE often diminish once the individual exits the water and rests; however, it is crucial for anyone experiencing suspected SIPE to receive medical assistance to assess oxygen levels and, if needed, remove fluid from the lungs.

The sensation of breathlessness and coughing up blood-streaked fluids can be distressing in and of itself. Moreover, if unchecked, SIPE may result in further complications such as increased pressure on the right side of the heart, leading to ventricle failure. Hence, it’s critical to recognize the symptoms and seek medical evaluation. This is especially relevant in the realm of triathlon and endurance sports, where the urge to push through and continue with the race or training can increase the chance of more substantial complications.

Signs & symptoms

Occurrences of SIPE remain relatively rare – studies project a 1.4% prevalence rate among triathletes. Nonetheless, given that much about the condition is still unclear, its true prevalence has not been documented. Amidst the growing popularity of cold water swimming and ‘extreme’ triathlon events, it is vital to be aware of SIPE’s signs and symptoms, especially since it can arise ‘out of the blue’ in otherwise healthy individuals without prior symptoms before entering the water.

Signs and symptoms of SIPE may consist of some or all of the following:

• Breathlessness disproportionate to effort levels
• Unexplained and/or uncontrollable coughing not linked to water inhalation
• Coughing up frothy, pink-tinged fluid or phlegm (blood-streaked sputum)
• Tightness in the chest
• Crackling/whistling/wheezing sounds from the chest

Risk factors

Current studies have identified several potential risk factors that may elevate the chances of SIPE occurring – although it is vital to note that one could meet all these criteria and not experience SIPE, given that the exact cause remains unidentified. Potential risk factors include:

• Excessive hydration prior to swimming – it is suggested that significant fluid intake, particularly with salt tablets, before entering the water may contribute to the overall increase in hydrostatic pressure.
• Wearing a snug wetsuit – further adding to the increase in pressure, which in turn escalates the pressure on blood vessels.
• Cold water
• Pre-existing high blood pressure and/or underlying cardiovascular conditions
• Overexertion and/or inadequate warm-up
• A previous history of SIPE – research indicates recurrence rates ranging from 13-75%

What to do if you experience SIPE symptoms while cold water swimming

If you or a companion in the water begin to display symptoms of SIPE, exiting the water immediately is crucial. This action will relieve the elevated pressure induced by immersion and lessen exertion levels. Symptoms generally worsen the longer you swim and exert, so resist the urge to push through and hope it resolves. Struggling for breath and coughing uncontrollably is hardly a pleasant swimming experience!

Once you are back on dry ground, it is advisable to take a seat and rest but remain upright for fluid drainage. Many individuals report that symptoms resolve on their own within 48 hours. However, if you face a suspected SIPE episode – even if you feel better quickly – it is still advised to consult a doctor/health professional to verify the fluid has drained, your oxygen levels are normal, and no underlying causes are present. And don’t hesitate to seek urgent medical attention if symptoms persist upon returning to dry land.

Remember SIPE and other adverse effects of cold water swimming are rare

All of this may sound somewhat alarming. While it’s important to be thoroughly informed about all the possible risks associated with swimming in cold water so you can mitigate them and act before anything develops into a severe issue, it’s equally important to remember that cold water swimming offers a plethora of benefits. When done safely, wild swimming experiences can be enjoyable throughout the year! Check out our cold water swimming gear guide to ensure you have everything necessary to relish the water this winter.