The Survival Rule of Threes: An In-Depth Explanation

Most people don’t think about how quickly a situation can turn deadly in the wilderness and many people struggle with what to prioritize when it comes to stockpiling for an emergency or SHTF situation.

When you first begin to read about prepping, one of the things you see referenced often is the “survival rule of threes”. Preppers adapted the rule of threes from wilderness and survivalists but it can be used to help you prioritize in just about any type of emergency.

The Survival Rule of Threes:

You can live up to…

  • 3 Minutes Without Air
  • 3 Hours Without Shelter
  • 3 Days Without Water
  • 3 Weeks Without Food

While not hard and fast, the rule refers to the amount of time an average adult can go without certain resources before it becomes fatal.

If you look at these guidelines, what would you determine is the most important thing to secure first? It’s clean or fresh air, right?

Since you can only survive 3 minutes without air to breath that would be your priority if you felt your supply of air was in danger.

Instead of wasting time trying to determine which tasks should be done first, you can use the survival rule of threes to guide your next steps.

There are always exceptions to the rule of course, and it should be treated more like a guideline than a set-in-stone rule. Sometimes you will have a logical reason to disregard it.

Let’s imagine for a moment that you and some friends decide to get together for a day of hiking up a mountain in your local area.

You’ve hiked before, you and your four friends get together every year for the day just not on this specific mountain.

You usually hike in the summer time, but this year some of your friends weren’t available until mid-fall. For the sake of our example, let’s say it’s late September.

You arrive with your friends at the parking area below the trail which will take you up the mountain where you’ve decided to hike. Everyone clamors out with their day packs and you all head up the trail.

After about an hour you pass a sign on the trail that indicates cell service beyond this point is sporadic, and you tease each other about which one of you will go into texting withdrawal first.

It’s great to see old friends, and you spend a good part of the morning pointing out nature’s wonders as you hike up the trail.

About halfway up the mountain, John complains of a mild headache and admits he skipped breakfast and probably just needs to eat.

Everyone is “starving” from the morning’s hike by now anyway, and the group stops for lunch and quickly devours the food they brought.

Someone points out that the map shows a stream not far off the trail and since it’s a warm day for September, the group decides to head that way and cool off by wading.

After about forty-five minutes in the stream, the group heads back to the trail and continues up the mountain.

Finally, the group arrives at the top of the mountain trail, nearly 8,000 feet in elevation. The view from here is breathtaking and time flies by as you wander around the summit snapping photos of the valley below and the view of nearby mountains.

John who has just been sitting on a nearby boulder, complains that he is short of breath, dizzy, and feeling very fatigued and wants to head back.

You pull out your cell phone and wireless hot spot and consult your American Red Cross First Aid App. From John’s symptoms, it appears he could be suffering from early stages of altitude sickness.

The instructions suggest rest as a first step but since John was just sitting while others were taking photos the group decides to take the next step and proceed to a lower altitude to see if that helps.

Since wi-fi is working but cell service is not, you send a quick message to John’s wife back home to let her know what’s going on and tell her you are heading back down the mountain.

John seems to be moving okay and is showing no signs of confusion, but he is complaining about being fatigued, so frequent stops are needed to let him rest for several minutes at a time.

By the time you reach the spot where the group ate lunch, it’s already very late in the afternoon.

It’s obvious you won’t make it back down the mountain before dark, and it looks like you’re going to have to spend the night somewhere along the trail. It will be dark in several hours.

John seems to be breathing easier but the temperature has dropped significantly as the sun goes down and it’s getting cold fast.

Now what?

A quick inventory of the supplies that everyone brought along with them for this day hike reveals that between the five of you there is less than a liter of water left.

Disclosure: This post has links to 3rd party websites, so I may get a commission if you buy through those links. Survival Sullivan is a participant in the Amazon Services LLC Associates Program. As an Amazon Associate, I earn from qualifying purchases. See my full disclosure for more.

Supplies also include a couple of granola bars, some peanut butter crackers, a lighter, a LifeStraw, two canteens, two Mylar emergency blankets, a set of walkie-talkies, and a paracord bracelet.

Your first instinct may be to find more water or to look for wood to start a fire or to find more food or even figure out a way to get help to the mountain since your cell phone is still out of range.

Think Again About the Rule of Threes

  • 3 minutes without Air (John’s breathing is better and he’s on the mend)
  • 3 hours without Shelter (definitely a need)
  • 3 days without water if you have shelter from extreme weather (you have less than a liter but there’s a stream nearby)
  • 3 weeks without food if you have shelter and water

When you climbed too high on the mountain for example and John experienced trouble breathing. Your first order of business was to move lower down the mountain to make breathing easier for John.

In your home or during a bug out, you’d want to have something on hand that would quickly help you to protect the quality of the air you breathe or to filter it such as a bandana or an N95 mask if air quality was compromised.

Immediate symptoms from lack of or inadequate air can be: shortness of breath, headaches, coughing, gasping, chest pain, and your nail beds changing color.

Longer term effects of lack of air or inadequate air are weakness and fatigue, confusion, disorientation, lack of consciousness, and even brain damage.

The next critical resource, believe it or not, is a shelter. This one trips people up sometimes because their instinct is to secure food, water, or fire first.

But shelter, especially in extreme weather conditions, is a very critical resource. The average adult can only survive three hours without protection from the elements whether it be extreme cold, extreme heat, or extreme rain/the wind.

Good manual dexterity (tying shoes, working a button or tying knots begins to suffer in temperatures below 50 degrees Fahrenheit.

Therefore, as long as the air you are breathing is not in danger, the first thing to secure is shelter to protect you from the elements.

If it is cold weather, then yes, you would include building a fire under this category for added warmth.

You’d be surprised how long you can survive in temperatures below zero if you have adequate shelter that blocks out wind and rain.

The immediate effects of not having shelter in extreme weather can be: sunburn, shivering, cold or numb extremities and face, cold diuresis or “the need to pee,” red cheeks and nose, or extremities, “goose” bumps due to horripilation, and chapped lips or skin.

Long-term effects of not having adequate shelter in extreme weather are frost nip and/or the more serious frostbite, sunstroke, heatstroke, and sun poisoning.

Once you have your shelter in place, the next thing to think about is water. The average healthy adult can only survive approximately three days without water.

You may be 100% certain that you can get back down the mountain once it’s daylight. But you will be exerting yourself and so will others in your group.

The sun will come out, and it will be warm which will cause you to sweat and expel water. Having enough water for the trip back down the mountain will be important to your success.

Immediate symptoms of not having water are thirst, dry throat, chapped lips, nausea, and more.

Long-term effects of not having adequate water are: disoriented, hallucinations, and more depending on the length of time and health of the person.

Even though not having food to eat might cause you more immediate discomfort than not having water or shelter, it is entirely possible for an average adult to survive up to 3 weeks and sometimes longer without food.

Immediate symptoms of not having food are: a headache, stomach rumbling, stomach pain, feeling dizzy or weak.

Long-term effects of not having food are: muscle weakness or lethargy, melancholy or panic, weight loss, low pulse rate and lowered blood pressure, slowed speech, and even organ damage.

Exceptions to the Survival Rule of Threes

As we mentioned earlier the survival rule of threes was built around the premise that the person in danger is an average healthy, physically fit adult.

There are of course certain people who are the exception to this rule and therefore are at risk of serious health problems or death much sooner than the time frames indicated by the rule of threes. These people are:

  • The elderly
  • Young children
  • Diabetics
  • Severely underweight or overweight people
  • Anyone with chronic or pre-existing health problems

Now let’s get our group of friends settled in for the night so they can hopefully get down off the mountain in the morning.

You and your group know you need water since it looks like you may have to spend the night and John isn’t feeling well.

The Survival Rules of Threes guideline indicates that shelter should take priority over water and the group realizes that everyone, especially John, needs shelter from the wind and falling temperatures before it gets too dark.

Since are still four able members of the group left, the decision is that Bob and Sue will go for water from the creek everyone waded in earlier, and on the way back from getting the water, they will collect firewood for a fire.

You and Jack will stay with John on the trail near where the group ate lunch and collect some pine needles, branches, and other materials from the nearby woods to form a barrier against the cold ground.

Jack will also use the paracord bracelet and one of the Mylar blankets to erect a lean-to with the open side facing the trail where the fire will be built. John is wrapped in the second Mylar blanket.

Jack hands one walkie-talkie to Sue and gives Bob the mini-flashlight from his own keychain in case it gets darker before they get back to the trail. Bob and Sue set off for the stream with the LifeStraw and the two canteens.

You and Jack start collecting materials first and then proceed to work with the paracord to get it long enough to string between two trees.

About an hour or so later, your group is huddled under the lean-to with a fire built and two canteens of filtered water. The natural materials Jack found are a good barrier from the cold ground.

You use your hotspot and phone to communicate with a local ranger station and let them know where you are and what’s going on.

They tell you they are sending a guide and EMTs to get you down the mountain safely tonight rather than wait till morning because a storm is predicted overnight.

Thanks to the Survival Rule of Threes and some calm decision-making, you’ll be home in a couple of hours no worse for wear. The group decides to divvy up the granola bars for “supper” and settle in till help arrives.

From just this one example, hopefully, you can see how the Survival Rule of Threes can help guide your survival decisions but not dictate them. There will always be exceptions.

But if you understand the basic concept, it will help you to make informed decisions about when to break the rules and when to stick to them.

rule of threes Pinterest

1 thought on “The Survival Rule of Threes: An In-Depth Explanation”

  1. Good article. My quick reaction would have been to go for water. But can see why shelter is even more important! And if someone was feeling funky, would have just stopped and turned around! But lots of people don’t so good scenario.

Leave a Comment

Your email address will not be published. Required fields are marked *