How swimming in cold water could treat depression

The surprisingly simple treatment could prove promising for doctors and patients seeking to treat depression without medication.

  • A new report shows how cold-water swimming was an effective treatment for a 24-year-old mother.
  • The treatment is based on cross-adaptation, a phenomenon where individuals become less sensitive to a stimulus after being exposed to another.
  • Getting used to the shock of cold-water swimming could blunt your body's sensitivity to other stressors.

As antidepressant prescriptions have surged in recent years, some doctors and patients have been diligently searching for safe and effective ways to treat the debilitating condition without drugs.

Now, a recent case report published in the British Medical Journal describes the promising signs of a surprisingly simple non-pharmacological treatment: cold-water swimming.

The report, which served as the basis for an episode of "The Doctors Who Gave Up Drugs"—a BBC One show—described how a 24-year-old mother named Sarah had approached doctors with one goal in mind: to get rid of her depression and the medications she'd been prescribed to treat it. Those drugs put her in a "chemical fog," she said.

Under the supervision of Dr. Chris van Tulleken, who co-authored the new report, Sarah started reducing her dosage of antidepressants and began swimming in water with temperatures near 60 degrees Fahrenheit. Dr. van Tulleken, who himself practices cold-water swimming, described his experience with the treatment to the BBC:

"Underwater, I feel an intense mixture of burning pain and, even after doing this for years, a little panic. But it's the only time the anxious negative chatter in my head is truly silenced. After two minutes, as my skin reaches the same temperature as the water, I start to feel comfortable and my breathing slows. After even a brief swim, I feel elated for hours and calm for days."

After four months of cold-water swimming, Sarah reported that her symptoms had stopped and that she was off all medications.

How does cold-water swimming help depression?

"One theory is that if you adapt to cold water, you also blunt your stress response to other daily stresses such as road rage, exams or getting fired at work," van Tulleken told The Guardian.

This theory is based on an idea called cross-adaptation, which is defined as the temporary loss of sensitivity to a stimulus following exposure to a different stimulus. In other words, cross-adaptation enables you to steel yourself against one kind of stressor by undergoing another.

But until further research is conducted, it remains unclear why exactly cold-water swimming seems to combat depression and also whether effects gained from cross-adaptation could last over the long term.

Depression is one of the leading causes of disability in the U.S., causing an estimated $210 billion of productivity loss every year. Some 13% of Americans are currently prescribed antidepressants, many of whom might be interested in an effective, non-pharmacological treatment for the condition.

How to swim in cold water safely

(Photo by Charlie Crowhurst/Getty Images for IRONMAN)

Although it may help treat depression, swimming in cold water needs to be done safely.

Cold-water swimming can be dangerous because drastic temperature changes can trigger rapid increases in your breathing and heart rate. The Outdoor Swimming Society offers these six tips for doing it safely (though you should consult your doctor if you have pre-existing medical conditions):

1. ACCLIMATIZE

As the temperature drops, just keep swimming, and your body will get used to the cold.

2. BE SAFE

Open water can be dangerous. Only ever swim where it is safe, and make sure you can enter and exit the water quickly and easily. Never swim on your own.

3. WEAR THE RIGHT KIT

Wear a swimming hat, or two, to help preserve body heat. You can also wear neoprene gloves, booties, a balaclava, or a wetsuit—whatever you feel comfortable with.

4. NO DIVING

Do not dive or jump in unless you are used to the cold water. Cold water can cause gasping and cold water shock, which can be dangerous.

5. KNOW YOUR LIMITS

As the temperature drops, decrease the amount of time you spend in the water. In winter, swimmers often only swim for one or two minutes at a time.

6. WARM UP SLOWLY

Don't have a hot shower. Hot water can actually cool your core, which can be dangerous. Instead, make sure you have plenty of warm clothes, wrap up well, and have a hot drink.

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Yale scientists restore brain function to 32 clinically dead pigs

Researchers hope the technology will further our understanding of the brain, but lawmakers may not be ready for the ethical challenges.

Still from John Stephenson's 1999 rendition of Animal Farm.
Surprising Science
  • Researchers at the Yale School of Medicine successfully restored some functions to pig brains that had been dead for hours.
  • They hope the technology will advance our understanding of the brain, potentially developing new treatments for debilitating diseases and disorders.
  • The research raises many ethical questions and puts to the test our current understanding of death.

The image of an undead brain coming back to live again is the stuff of science fiction. Not just any science fiction, specifically B-grade sci fi. What instantly springs to mind is the black-and-white horrors of films like Fiend Without a Face. Bad acting. Plastic monstrosities. Visible strings. And a spinal cord that, for some reason, is also a tentacle?

But like any good science fiction, it's only a matter of time before some manner of it seeps into our reality. This week's Nature published the findings of researchers who managed to restore function to pigs' brains that were clinically dead. At least, what we once thought of as dead.

What's dead may never die, it seems

The researchers did not hail from House Greyjoy — "What is dead may never die" — but came largely from the Yale School of Medicine. They connected 32 pig brains to a system called BrainEx. BrainEx is an artificial perfusion system — that is, a system that takes over the functions normally regulated by the organ. The pigs had been killed four hours earlier at a U.S. Department of Agriculture slaughterhouse; their brains completely removed from the skulls.

BrainEx pumped an experiment solution into the brain that essentially mimic blood flow. It brought oxygen and nutrients to the tissues, giving brain cells the resources to begin many normal functions. The cells began consuming and metabolizing sugars. The brains' immune systems kicked in. Neuron samples could carry an electrical signal. Some brain cells even responded to drugs.

The researchers have managed to keep some brains alive for up to 36 hours, and currently do not know if BrainEx can have sustained the brains longer. "It is conceivable we are just preventing the inevitable, and the brain won't be able to recover," said Nenad Sestan, Yale neuroscientist and the lead researcher.

As a control, other brains received either a fake solution or no solution at all. None revived brain activity and deteriorated as normal.

The researchers hope the technology can enhance our ability to study the brain and its cellular functions. One of the main avenues of such studies would be brain disorders and diseases. This could point the way to developing new of treatments for the likes of brain injuries, Alzheimer's, Huntington's, and neurodegenerative conditions.

"This is an extraordinary and very promising breakthrough for neuroscience. It immediately offers a much better model for studying the human brain, which is extraordinarily important, given the vast amount of human suffering from diseases of the mind [and] brain," Nita Farahany, the bioethicists at the Duke University School of Law who wrote the study's commentary, told National Geographic.

An ethical gray matter

Before anyone gets an Island of Dr. Moreau vibe, it's worth noting that the brains did not approach neural activity anywhere near consciousness.

The BrainEx solution contained chemicals that prevented neurons from firing. To be extra cautious, the researchers also monitored the brains for any such activity and were prepared to administer an anesthetic should they have seen signs of consciousness.

Even so, the research signals a massive debate to come regarding medical ethics and our definition of death.

Most countries define death, clinically speaking, as the irreversible loss of brain or circulatory function. This definition was already at odds with some folk- and value-centric understandings, but where do we go if it becomes possible to reverse clinical death with artificial perfusion?

"This is wild," Jonathan Moreno, a bioethicist at the University of Pennsylvania, told the New York Times. "If ever there was an issue that merited big public deliberation on the ethics of science and medicine, this is one."

One possible consequence involves organ donations. Some European countries require emergency responders to use a process that preserves organs when they cannot resuscitate a person. They continue to pump blood throughout the body, but use a "thoracic aortic occlusion balloon" to prevent that blood from reaching the brain.

The system is already controversial because it raises concerns about what caused the patient's death. But what happens when brain death becomes readily reversible? Stuart Younger, a bioethicist at Case Western Reserve University, told Nature that if BrainEx were to become widely available, it could shrink the pool of eligible donors.

"There's a potential conflict here between the interests of potential donors — who might not even be donors — and people who are waiting for organs," he said.

It will be a while before such experiments go anywhere near human subjects. A more immediate ethical question relates to how such experiments harm animal subjects.

Ethical review boards evaluate research protocols and can reject any that causes undue pain, suffering, or distress. Since dead animals feel no pain, suffer no trauma, they are typically approved as subjects. But how do such boards make a judgement regarding the suffering of a "cellularly active" brain? The distress of a partially alive brain?

The dilemma is unprecedented.

Setting new boundaries

Another science fiction story that comes to mind when discussing this story is, of course, Frankenstein. As Farahany told National Geographic: "It is definitely has [sic] a good science-fiction element to it, and it is restoring cellular function where we previously thought impossible. But to have Frankenstein, you need some degree of consciousness, some 'there' there. [The researchers] did not recover any form of consciousness in this study, and it is still unclear if we ever could. But we are one step closer to that possibility."

She's right. The researchers undertook their research for the betterment of humanity, and we may one day reap some unimaginable medical benefits from it. The ethical questions, however, remain as unsettling as the stories they remind us of.

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