Someone recently told me about the Survival Rule of Threes. It implied that nearly all aspects of survival can be tracked by a degree of time equal to three. But is it trustworthy?
The original rule goes as follows:
You can survive three minutes without oxygen
You can survive three days without water
You can survive three weeks without food
Sometimes, this idea is shared around with a few extra additions, such as “you can survive three hours in any harsh environment,” or three months without any form of companionship. I even found one variation that claimed that you take three seconds to mentally process any emergency.
It’s an interesting idea, this rule of three, but I’m skeptical. A few of these sound inaccurate. So I did some of my own research and here’s what I found.
1. Three Minutes Without Air
The obvious answer is that this is not guaranteed. Trained divers can hold their breath as long as 11 minutes (though that’s expert numbers). Your average person can only willingly hold their breath for about 30 seconds. While it’s not been easy finding reliable numbers online, Michigan University claims that it takes five to ten minutes of no oxygen before serious brain damage will occur. It takes three minutes without oxygen for brain damage to start, and only about 30 seconds without oxygen before you fall unconscious. Mind you, this is when oxygen is gone, meaning all the air in your lungs has been “spent”.
2. Three Hours in Harsh Conditions
This one is too vague, to be honest. The real answer is determined by HOW harsh the weather is. The National Weather Service claims that it only takes 30 minutes to get frostbite in weather under 32 degrees. The risk rises rapidly the colder and windier it gets, especially if you’re wet. If you’re in water under 60 degrees, it’ll take less than three hours to lose consciousness. It will only take 15 minutes to pass out in ice water. If you’re wet but on land, we figure it’ll sit somewhere in between.
What about heat, then? More than 15 minutes in 140 degree heat will lead to loss of consciousness. Survival time will grow longer the colder it gets, how hydrated the person is, and whether there is shade/breeze. As long as the body’s internal temperature stays below 108 degrees, they should survive, but not without damage.
3. Three Days Without Water
Let’s assume you’re not in a desert. Hot, dry climates will without a doubt speed up the dehydration process. The human body needs water to feed to virtually all cells in our body. We lose a lot of it expelling waste, sweating, and breathing. Without water, we can’t do that, leading to, most likely, intoxication when the kidneys cannot expel the toxic build up via the urine.
That said, people can survive a surprisingly long time without water. Generally speaking, a healthy young person can go three or four days without any harm (though it’s not good for them). In more extreme situations, people have been known to go 12 days without any water.
4. Three Weeks Without Food
Like with the water, this one is also a low-ball number. The average human can survive one to two months without any food. When starving, the body will consume itself to survive. It starts with internal carbs, then fat, then muscle. After that it starts breaking down vital organs. That phase generally happens after a month. Things that can affect how long or short this process is depends on metabolism, fat levels, and physical constitution.
5. It takes Three Seconds to Make a Decision in an Emergency
I’m not even sure where this one started. It sounds just silly to me. According to a study in 2013 by Ariel Rubinstein about decision-making, there IS a correlation between quickly deciding something and whether that was the correct choice. However, their research implies that, in most quick-time questionnaires, the results between thinking about it for three seconds and for 30 seconds were essentially the same, yielding low-success results. Taking an additional 30 seconds, totaling to 1 minute, has a 700% more likely chance to be correct. So in short, three seconds is an arbitrary number given to reaction times.
6. Three Months Without Companionship
This is a classic horror story trope. What happens when you put a man in isolation for too long? There’s even a Twilight Zone episode about it, the first episode ever, in fact. In the show, a man was in an isolation chamber for about 20 days before undergoing a hallucinogenic psychosis. But is it based on anything real? Human psychology is a relatively new field and not much is known about it. Is there even an upper limit to social isolation?
In reality, the number will extremely vary by person. Extroverted folks will likely crack under the pressure far sooner than introverts. Some people actually prefer to be alone, choosing cabin lifestyles away from others.
The Rule of Threes for Survival is Still Good
While the actual facts may not agree with it, I think the rules are still a good thing to follow. Some numbers are an undershot of survival (with arguments against the oxygen and environment one). Assuming you can survive shorter than you can is a lot safer than assuming longer.
Additionally, this gives an easy reference for priority. Oxygen, Environment, Food, Water. Each problem should be addressed in that order of importance. If you can only survive for three hours in the heat, it’s much more important to resolve that than starving to death.
The more arbitrary ones, such as reaction time and companionship, are not based on any conclusive evidence, however.
So in conclusion: the Main rule of threes isn’t the most accurate, but might help you consider what to prioritize in a survival scenario.