Rule Of Three – Survival Priorities And Decision Making

Knowing and adapting to the rule of three for survival. It could make the difference between life and death when making critical decisions in an environment of potential or actual disaster.

The Rule Of Threes is a way to help remember a set of priorities to sustain life.

Here’s what I mean, and these are accepted generalities. However they are close enough to get the point across…

Likely and generally, at most you can only survive for:

  • 3 Minutes without air 
  • 3 Hours without shelter in a harsh environment
  • Three Days without water 
  • Three Weeks without food 

The reason for the Rule of threes? It’s to help focus on the most immediate problem first. And to simply understand the realities. Keep reading…

Rule of Three’s – For Survival

The survival rule of 3’s are commonly referenced in the context of outdoor/wilderness survival. However it really doesn’t matter the situation, or where it happens… The priorities are relevant, regardless.

Example: If your immediate threat to survival is hypothermia, there’s no need to think about how you’re going to get food or water. Because if you’re wet, cold, and shivering, you are going to be out of commission in several (~3) hours or less without mitigation. Maybe even dead…

Generally speaking, you can only survive for…

3 MINUTES Without Air

Someone who is not breathing has only minutes… So, logically, it is priority #1. (Although I mention another priority below, which could supersede this one, depending on circumstances. Security.)

I’ve read that most people can hold their breath approximately 30 seconds, up to 2 minutes if you are in excellent health.

You have to breathe for survival. Your body needs air / oxygen. Additionally, breathing clears the carbon dioxide (CO₂) that’s building up in your blood.

How Long Can the Brain Go Without Oxygen? A Timeline

  • Between 30-180 seconds of oxygen deprivation, you may lose consciousness.
  • At the one-minute mark, brain cells begin dying.
  • At three minutes, neurons suffer more extensive damage, and lasting brain damage becomes more likely.
  • Five minutes, death becomes imminent.
  • At 10 minutes, even if the brain remains alive, a coma and lasting brain damage are almost inevitable.
  • At 15 minutes, survival becomes nearly impossible.

Any situation that impedes breathing (or the blood’s ability to circulate Oxygen) is an immediate threat to survival.

An example of this risk are those who may have severe asthma, or allergic reactions. This could be life threatening without an inhaler or epinephrine. Consider a near-drowning incident. Do you know how to attempt clearing the lungs of a victim who has swallowed water so that they can breath? Another example may be someone choking on food. This is another life threatening situation with only minutes to survive.

[ Read: How-to do Adnominal Thrusts ]

3 HOURS Without Shelter (Body Core Temperature)

Shelter. Protection from the elements. Your clothes count too.

This rule of three gives you about 3 hours if your body core temperature is unsafe beyond thresholds to regulate. Too cold, or too hot. When analyzing deaths of persons lost in the wilderness, most lose their life due to hypothermia (cold).

The human body has a normal core temperature between 97˚F and 99˚F, but on average, a normal body temperature is 98.6˚F (37˚C).

To maintain this temperature without the help of warming or cooling devices, the surrounding environment needs to be at about 82˚F (28˚C).

Clothes aren’t just for looks — they’re necessary to keep warm. You can usually bundle up in more layers during colder months, and you can use fans or air conditioners in warmer months to maintain a healthy core temperature.

Wet and Cold. Those are two very bad things together. Quite potentially becoming deadly. Seeking shelter / protection from the cold, wind, and wet, can become extremely important in a survival situation.

When your body core temperature drops, your heart, nervous system and other organs can’t work normally. Left untreated, hypothermia can lead to complete failure of your heart and respiratory system and eventually to death.

Signs and symptoms of hypothermia include:

  • Shivering
  • Slurred speech or mumbling
  • Slow, shallow breathing
  • Weak pulse
  • Clumsiness or lack of coordination
  • Drowsiness or very low energy
  • Confusion or memory loss
  • Loss of consciousness

Plan for changing environmental conditions on any excursion. Pack for it. I live in the mountains. I can attest to the potential radical differences in temperature and changing weather conditions simply based on elevation and location. Experienced hikers ‘get this’. However, many others do not.

Staying dry is so very important. Do you have the right clothing with you or on you? Got enough layers? What about rain gear? Got an extra pair of dry socks? (for example). Do you have the ability and gear to make a temporary shelter? A way to make a fire?

[ Read: Hypothermia – How To Prevent It ]

[ Read: Fire Starting Kit List ]

3 DAYS Without Water

Another really important rule of three! Generally, you might only survive for about three days without any water whatsoever. Maybe a few more if you’re lucky.

Without enough water, the kidneys use more energy and wear on tissue. Your kidneys need to function adequately to flush out waste from your blood. Eventually, your kidneys will cease to function without adequate water intake.

Some of the side effects without enough water:

  • a lack of energy
  • tiredness
  • injury, like heat cramps or heatstroke
  • brain swelling
  • seizures
  • hypovolemic shock (description)
  • kidney or other organ failure
  • death

You must stay hydrated. The second leading cause of lost persons death in the wilderness is dehydration. No water to drink. Not being prepared with enough water.

Water is a valuable survival commodity! Always treat suspect water before drinking it. And treat all water as suspect! Got a drinking water filter?

Being dehydrated hinders the ability of your body to maintain core temperature.

Tip: Don’t eat snow. Only do this as a last resort. The cold snow will lower your body core temperature.

[ Read: How-to Tell If You’re Dehydrated ]

[ Read: Dehydration Symptoms, Prevention ]

3 WEEKS Without Food

Few short term survival situations require food. Why? Because the human body can survive for weeks without food. We are somewhat inherently adapted to short periods of fasting (starvation). The rule of threes here is approximately 3 weeks.

There’s a lack of scientific research on starvation because it’s considered unethical to study starvation in human subjects. However, there are some studies that explore old research on starvation, as well as examine more recent occurrences of starvation in the real world. Survival without food ranges from a few weeks, to three weeks, to sometimes longer – depending on variables.

A “rule of thumb” appears to be (generally) three weeks.

Some of the side effects of starvation include:

  • faintness
  • dizziness
  • blood pressure drop
  • slowing heart rate
  • hypotension
  • weakness
  • dehydration
  • thyroid malfunction
  • abdominal pain
  • low potassium
  • body temperature fluctuation
  • post-traumatic stress or depression
  • heart attack
  • organ failure

Given that we can survive for a time without food, consider your other priorities first, as well as efforts to get out of the situation (and/or rescue).

On the other hand, if your situation appears to be long-term, then yes you will need to somehow acquire food.

One thing though… Without enough calories you will quickly become increasingly unable to help yourself out of the situation. Energy stores will deplete. Try going without food for a day… It’s not fun. Now imagine days, and days… desperation will set in for sure.

[ Read: Food Storage List For 1 Year ]

Other Considerations

With that said, you might say that AIR, SHELTER, WATER, FOOD, is the proper priority order for survivability.

Depending on the situation, circumstance, or environment, you might also insert SECURITY as #1 (before AIR) when there is an immediate threat to life. You might say the rule of three for security is 3 seconds…depending…

You might also add the concept of ATTITUDE. A positive attitude to help overcome a stressful situation, and making the right decisions.

Here’s another rule of three… Someone on the blog said “3 people cannot keep a secret”. Another said “3 seconds without common sense or thinking.”


  1. People need to think about this before they bug out to parts unknown. Make sure you have a good plan before leaving the safety of your home. Unless you have the money to own a well stock retreat plan to stay put. I like to think that I am that mean, lean, marine I once was but common sense tells me that this 66 year old marine and his wife would not make it very long trying to live on the road. I have all the things I need right here at home. Just my two cents input.

      I personally would agree with you 1000%, unfortunately every situation is different, and some should very much research the need to “Bug-Out” (if I live in a 50 story apartment complex in the middle of NYC for instance), as much as those that have decided to “Bug-In”, need to remember there always may be a need to Bug-Out (fire, Nuke fallout, overrun with ISIS, etc.) having an alternate location (retreat) is very important.
      Being flexible is very important, and the ability to gather information (communications) to make the best decision.

      1. Very true and I agree. Some people will have no choice but to bug out. I also have a bug out plan if I have to leave. Most of the people from the big cities will not be welcome in the rural areas and most do not have the skills to survive.

        1. @ RUNNING BEAR
          Hence if you do live in the cities and are planning on using your Groups of three, you have better have a location and have talked to those there about “what if”. AND bring your skills and everything you can. Also stockpile some goods if possible.

          Did not mean to get into Bugging-Out, but I think this ties into the 3’s as maybe “3 days” to find a place to hold up, as the “family” is not going to be able to walk (whatever) longer than that, could you imagine young children in a situation like that, 3 days is all you’re going to get I would bet..

    2. @ RUNNING BEAR,

      I agree. Running is a young man’s game. Not only is it a young man’s game, it’s a young man/woman who actually knows what the hell they are doing, game. I see on some sites folks describing their bug out bags that must weigh well in excess of a hundred pounds. I respectfully submit they are living in fantasy. I’ve lived a long, full life. I will live, or die, in familiar surroundings.

  2. Great reminder Ken, I do it a little differently than yours but the idea is the same;

    1) Three seconds without protection, think Situational Awareness, Firearm Protection
    2) Three minutes without Air, which is pushing the limit for most people?
    3) Three hours without Shelter, less in severe conditions, IE falling into iced lake or river.
    4) Three days without water, unfortunately at 2 days you’re already becoming delusional.
    5) Three weeks without food, again after about two weeks you’re beginning to lose your ability to think correctly
    6) Three months without companionship or outside contact with other people. Loneliness will drive most crazy and delusional quite quickly, think solitary confinement here.
    7) Three years without rebuilding “life as we know it”.

    But those are just my thinking.

    1. I would would like to think we would have three more years, but with things starting to happen so fast, SHTF in three hours, three days or three months!! One thing is certain, daylight is burning, we can’t afford to waste any of if. Every hour of prepping and every dollar spent on preps now will be multiplied many times when compared to those that have choosen other priorities.

      1. @ Being Watched
        I was meaning 3 more decades of HORABLE politicians. Heck I KNOW for a FACT, 3 more years is a definite…

        1. Good for you!!! I’m not going to be the one to wake you up from your dream!!

  3. About 3 minutes without air. When the pumper starts to fail, you might want a bottle of cayenne pepper stored in the kitchen. One doctor stated he never lost someone having a heart attack when giving them a cup of warm water mixed with a tablespoon of cayenne pepper. Administer while they are still having the attack. Takes only a few minutes to start working. You can google this. Another doctor stated he actually revived someone who heart stopped all together with a cup and warm water and cayenne pepper. Some fishy but research seems to verify this works. The pepper balances the blood pressure and feeds the heart. Also the other day my son had a cut he could not get to stop bleeding and he tried cayenne pepper. Stopped right away. Soldiers in WW II all had cayenne pepper to stop bleeding wounds.

    1. Its great, but darn the sting/burning when you put it on the wound lol

    2. CEEBEE, the romans also carried ground pepper with them when they went into battle. They used it to stop the bleeding.

    3. Being Watched, be very careful with celox, it has a tendency to burn the skin around the wound site. Talked to a couple of doc’s, they don’t like celox b/c it is hard to get out of the wound after it sets up.

    4. Yes, I found information about using cayenne pepper for heart issues based on Dr Christoper’s information at a web site with information on his theories and practices of herbal healing and wellness.

      Www (dot) herballegacy (dot) com (slash) Heart.html

      Our household has been researching herbal and other natural therapies in the past two years due to a lack of being able to get appointments and treatment for non-Covid medical issues. Some of the information presented here has been useful and effective for our ailments.

      As with any info, your mileage will vary.

  4. Every situation can be differant! When suffering from hyperthermia seconds count! Building a fire and removing wet clothing would be more important, or hypothermia, cooling off with a water soaked towel and drinking water would be more important.

    It all depends on the circumstances and the immenate threats that have to be overcome or elimenated.

      1. You might consider practicing with your skills using your supplies if you haven’t already done so. The placement of a fire big enough to deal with Hyperthermia would depend on if you are alone or with a group, the size and materials of construction of the shelter and whether the shelter is temporary or permenate.

        Good Luck!

        1. most weekends find me doing just that, my only point was that shelter and fire should be your first priority, once that is established you can begin to process water…this refers to a wilderness survival situation, not a shtf bug out…although the priorities are basically the same, saving the need for security and remaining covert.

        2. Beingwatched,

          Hyperthermia is “excessive body temperature”. Hypothermia is “low body temperature.


        3. Yep, I sometimes get them mixed, but the point was made that circumstances will dictate the priorities, example a fire that would generate smoke would not be good for trying to be covert and not being discovered when they start rounding up people to put in FEMA camps. A few cans of sterno when burning won’t generate smoke or odor.

          Being prepared when the bad stuff starts by having a plan A B C and D and having a descent recognition and reaction time of when to change to an alternate plan will be very important. Acting like a deer in headlights may get you killed or put those that are depending on you in danger.

          Different elements of time in different circumstances, well here’s one,
          the commondity of time to prepare is more valuable because we hare getting closer than most realize to the day when the short fuse will be lite!!!

  5. The Bible Sayeth: ‘A threefold cord is not quickly broken.’
    As far as grouping goes, we learned in the Military that small groups of three worked out pretty well. Can take care of themselves a lot better than two.

    1. And unfortunately when you have more than four you start getting into power games.

  6. Rule of 3 also applies to items and strategies.

    For example:
    – 3 ways to make fire, to purify water, cut something, shoot, etc.
    – always have at least three plans: A, B and C. Routes to BOL,


  7. And than there’s this rule of three. Three is two and two is one leaving one as none.

  8. People think three minutes without air means drowning or asthma attacks. However, there are others. Smoke from fire, either forest or home is a grave danger. Radiation, too, is a problem. Do you want to breathe radioactive air. In a part of Sweden which received winds from Chernobyl now have a huge cancer increase. Then, volcanic release of ash which is actually fine and sharp rock will cut your lungs. Chemical accidents will also release toxic fumes which you inhale.

    As a Prepper I have a full face swimming mask with the breathing hole covered in G95 ( Bioscarf) fabric. It sits on my night table. Should a chimney fire start during the night, I will be able to see and breathe as I exit.

    Stay frosty.

  9. 3hrs without a smoke and/or a stiff drink, …..
    in this messed up world?

    Now, your talking casualties.

  10. Hypothermia is a big one, out here people dont think about it but in reality is quite a common danger, anything that lowers your core temperature enough will kill you, there are many rescues in the crater or on ocean where people ended up exposed for an extended period and their bodies started shutting down, in the crater is most common, folks start out, looks like a beautiful warm hike then the clouds and fog roll in, its amazing how cold it gets and how fast at the 8,00-10,000 foot elevation. Same thing with the ocean, yea sure, its warm and sunny out, but get dunked in the ocean after losing a kayak or SUP board and 3 hours later they are doing a recovery in many cases.

  11. Wow !
    Mentioning ‘Hypothermia’ reminds me of what happened to several highly trained Army Special Forces guys, not too many years ago, in the swamps of northwestern Florida. Spending a 3-day survival camp-out, the temperature dropped below freezing during the night. Cold and wet, hypothermia set in and killed 3 of them. One was a fresh West Point top-of-his-class graduate, and the others were Sergeants.

    1. lol stupid officers and west point means nothing..

      The poor NCO’s should called it instead of getting themselves killed.

      1. That’s easy to say when someone spends all of their time in the rear with the gear or in the brig

  12. – Someone once commented that for a military (or any) small group the number should be four. The three that are the actual group and the extra one along as the trainee, who should be learning from the others.

    – Papa S.

  13. i have a deep well with a non electrical way of drawing it. many people here did not have electricity until the early 50’s until the REA’s came through and did just fine. we have a 100ft well and buckets, rope and pulley’s.
    water is everything IMO.
    what would water be worth in barter or for goods or services in 3-7 days?
    it cost me 2K to put down the a well and have it cased in 10yrs ago, no pumps, just a 6″ hole drilled, cased in and capped with a fernco. it’s great insurance for possible hard times ahead. i draw water from it every so often to check it.
    i may go hungry, but not thirsty, or die with a nasty ass.

    1. Concerning air: breathing in radiation or a poison gas also applies.

  14. Lauren, Want to address your question in a way that preserves it so using this article. Adding to the list of threes I would note that right now we’ve got three more decades of the Modern Grand Solar Minimum left. Many of us, myself included, will not see its conclusion, but you younger folks will. And you will age and become frail in the meantime, as will the family members of those of us who pass on in the meantime. And given this administration’s proclivity for engendering both inflation and shortages, we can only afford to do something once. Do the heavy lifting while you’re young – buildings, permanent fencing, etc. For me that includes rocking, graveling, or deeply wood chipping paths to outbuildings. They’re above the water when it rains hard. When I can no longer walk and carry stuff, I plan to have a small motorized something to help with that. I’ve got hand rails in the bathrooms. I plan on putting them in the hallway, too. Safety first!

  15. Handrails are a good idea. Paths will have to wait until I have a finished plan, but at the moment I intend raised woodchip paths with alternating handrails. Rock would be nice, but the material depends on availability and cost when I really start working on this place.

    Looks like the time-line for some of this has been accelerated, as a friend of mine will be moving in with me. She’s entirely wheelchair bound, so widening the doors and building a wheelchair ramp takes precedence.

    As far as the small motorized something, if you have a small wheeled cart and a straight shot from here to there, attach your cart to an electric pully. If your path is downhill it can carry itself and its load, building up the “momentum” to carry the unloaded cart back up the hill without electricity. Something to think about, anyway.

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