Should you take the plunge?
Many advocate for cold water immersion, but questions remain
Many winters ago, some friends and I decided to jump into a cold lake as part of a dare that grew out of control. With snow on the ground, we jumped in. I remember my heart skipping a few beats and feeling short of breath as I immediately crawled out of the water. Recently, some people have been advocating cold water immersion as a step toward healthy living, but is it healthy, dangerous or just bragging rights?
For more than 100 years, the Coney Island Polar Bear Club has been swimming in the Atlantic Ocean throughout the winter. The New Year's Day plunge has become a tourist event, an adventurer's destination and even a charity fundraiser. Bernarr Macfadden, a health advocate, founded the group in 1903 with the belief that cold water plunges were healthy.
Macfadden had a colorful, prosperous life. He grew his health magazine into a small publishing empire, promoted fasting, was seen as indecent for claiming that intercourse was healthy, was anti-white bread, considered doctors charlatans and promoted ampelotherapy, the belief that eating a large amount of grapes cured cancer. Macfadden's claims were like coin flips, he was right about half the time. So what about cold water immersion?
First, let's acknowledge a cold water plunge can cause near sudden death. A 2017 paper concluded that the evidence base for cold water swimming killing someone is more developed than the evidence it would “cure” someone.
The criticism of any study trying to draw conclusions on cold water swimmers is that it might not be the cold water.
How death happens
Death occurs by two different mechanisms. First, many of us are equipped with a “reflex” to uncontrollably gasp and even hyperventilate upon jumping into cold water. It does not take much water to aspirate to begin the drowning process. Jumping into deep, cold water is not recommended. And by cold, it isn't even freezing that is dangerous. Some people have this reflex initiate in 75-degree water. The second way a plunge can kill people is by causing an arrhythmia. The cold water stimulates both sides of our autonomic nervous system. Our heart receives signals to both slow down and speed up at the same time. This is particular dangerous in people with pre-existing heart disease.
Let's look at the other side. It's been known for decades that pre-cooling the body before exercising in hot weather improves performance. Athletes take advantage of the fact that the thermal conductivity of water is 24 times greater than that of air. Getting into cool water before short-duration exercise improves performance. At some point, the cooled person reaches the same temperature as the uncooled person and there is no further benefit.
Longer life?
Some people chose to do cooling unrelated to exercise. The theory is that cold water immersion decreases inflammation.
It has been shown that people with long life spans — those who are older than 85 — have low levels of inflammatory markers. Conversely, a high inflammatory score is associated with atherosclerosis, Alzheimer's, inflammatory bowel disease and depression.
Studies are relatively small and focus on frequent swimmers. It appears cold water exposure has metabolic effects that increase fat metabolism (more so in men) and decrease insulin resistance. There are also some studies that show immune mediators and antioxidants are increased. These all have theoretical health benefits but hard evidence is lacking.
The criticism of any study trying to draw conclusions on cold water swimmers is that it might not be the cold water. It might be that cold water swimmers are healthier, more active, better at breathing and reducing stress than people who wouldn't consider swimming in cold water.
But maybe that's the secret, get yourself in the mindset and shape to be a cold water swimmer and you will be a healthier person — even if you don't take the plunge.
Dr. Sal Iaquinta is the author of “The Year They Tried To Kill Me.” He takes you on the Highway to Health every fourth Monday.