Cold water exposure, along with many other seemingly unrelated stressors like aerobic exercise, hypoxia, even some types of psychological stress make a person resilient through so-called cross adaptation discovered by Soviet scientists decades ago.

What do the following items have in common?

• Aging
• Excessive exercise loads
• Psycho-emotional trauma
• Lack of physical activity
• Vitamin deficiency
• Smoking, narcotic drugs, alcohol
• Acute and chronic infections
• Extreme climate and weather conditions
• Ionizing radiation, electromagnetic fields
• Irrational nutrition, including excess of carbohydrates and animal fats
• Food with excess of heavy metal salts, nitrates, radionuclides

You are likely to answer, “bad choices.” 

Correct—even aging is a choice, up to a point—but it is not what the scientist who has compiled this list had in mind.

All of the above factors cause free radicals overproduction—obviously, bad news for health and longevity.

Most of the damage caused by free radicals—and defenses against them—take place within your mitochondria, the aerobic power houses of the cell. (Our online course SECOND WIND express explains how it works.) This is why Dr. Lane stated: “If we ever succeed in extending our lifespan to a healthy 130, I would be surprised if the big strides forward had not begun in mitochondrial medicine.”

The results of the following experiment by Prof. Meerson highlight the generality of cross adaptation’s protective effects—while validating most stupid things military recruits have had to endure since the beginning of time.

An experimental group of rats was put under “moderate restraint stress”—they were immobilized on their backs for 30min every other day for 24 days. The control group did not receive this “training.”

Then both groups were exposed to severe acute hypoxia. Almost half of the controls died in the first 10-20min. All of the rats from the experimental group made it to a least 30min, thanks to adaptations like a blunted stress reaction and thicker cell membranes fortified against free radicals.

Thus, doing something unpleasant and uncomfortable will improve your health and your odds of survival—provided you go about it like an adult.

If you have never squatted heavy, would you walk up to a barbell loaded with two times your bodyweight and try to lift it?

If you have not run in ages, would you enter a race?

Of course, not. Then why would you venture into icy water if the only cold exposure you have had lately was from ice cream?

Entering cold water unprepared could have a bad ending, such as a cardiac arrest. So, start by getting a medical clearance, then build up to freezing temps in a progressive manner, as you would training for strength and endurance.

The Soviets developed guidelines for cold water exposure that they called “tempering” many decades ago. Here is a summary.

Start outdoor swimming in the summer, August at the latest in places with cold climates. Let the change of seasons gradually adapt you to cold.

Temper at least twice a week, but no more than once a day. When the water finally gets noticeably cold—e.g., in October in the Midwest and the Northeast of the United States—limit your exposure to a maximum of: