Before you head out into the wilderness, I have one question for you: How are your survival skills? While you need not be a Bear Grylls to get out and enjoy the great wild wonders, it helps to have a basic understanding of the Survival Rule of Threes.

Most of us don’t get the chance to get out into nature very often, so it is important to get a heads up on the basics of surviving outdoors. The Survival Rule of Threes is an easy guideline to keep a clear head in the event you are required to think in terms of what to do first. You could say these items are listed as the hierarchy of danger levels, and they reveal how long a human can survive as follows:

The Rule of Three, Wilderness Survival

  • 3 minutes without air to breathe
  • 3 hours without shelter from the elements
  • 3 days without water
  • 3 weeks without food
These are not hard and fast rules meaning any given situation could present variables depending on the circumstances. We even see how on Anderson Cooper's blog that the Rule of 3's reflect the critical nature of reacting appropriately rather than becoming distracted by fear or the sensations that can distract us from the crucial prioritizing of these survival aspects.

In essence, you are treating the potential scenarios as triage, the same way medical emergency crews will respond to an emergency or a crisis. In the immediacy, the worst cases need the first attention, including evaluation to determine the severity of the threat to life. The most important of all is making sure the subject can breathe.

Rule of Threes: Surviving 3 Minutes Without Air

You can survive for three minutes without oxygen or in icy cold water. Even finding the smallest way of getting more air could be a life saver. Certain risks such as high altitudes, being caught in a fire, the potential for getting trapped under snowfall or any situation that could lead to being trapped under water or in icy cold water are some examples of life-threatening circumstances.

According to the Cleveland Clinic, without enough oxygen to the blood, the organs and tissues suffer. Hypoxia is a condition of severity that can be fatal in the short term. If it persist in the long term, it can affect the brain or the heart.

The symptoms of hypoxia can include any of the following:
  • Changes in skin color
  • Rapid or slow heart rate
  • Rapid or shallow breathing
  • Confusion
  • Cough or wheezing
  • Sweating
It is useful to be up on your first-aid and CPR procedures. Should you or someone in your party be choking, the Heimlich Maneuver can be used or self-applied by bending over a log or a rock. Even resorting to a crude tracheotomy in the worst-case scenario is better than watching someone simply expire.

Certain physical conditions can bring on these symptoms. Anyone who goes out that has asthma, anemia or allergies should take extra care to be aware of the challenges. Those who use life-saving tools such as an inhaler or an epi-pen should make sure to bring them along.

Rule of Threes: Surviving 3 Hours Without Shelter

It might seem like common sense to seek a food source when faced with surviving in the wild. There is a reason it is the last item in terms of priority. Shelter is more critical to protect you from the elements, specifically the extremes of being too hot, too cold or too wet.

Until you have faced the extremes of weather without shelter, it is often hard to conceive of how devastating it can be. If you have packed a survival tent, you are in fairly good shape. If you don’t have one, you must improvise.

There are many opportunities you can take advantage of for natural shelters, such as caves, stumps or logs. Otherwise, you can build a shelter, lean-to or debris hut by gathering the materials close at hand. You must consider a location away from any hazards that can be insulated from the ground, rain, wind or the air.

You can easily carry extra tarp and para-cord that are useful in setting up a simple shelter that can be accommodated for more than one person. You may need to have a source of heat, whether body-heat or a fire. Survival kits typically have a variety of methods included so that you can start a fire.

Remember: You are building a shelter, not erecting a mansion.

According to the J R Army Medical Corp., hypothermia is a potentially deadly environmental hazard. The nights get chilly fast, and hypothermia can set in within a few hours if you do not have sufficient clothing or perhaps you got stuck wearing wet clothes. It is dangerous to think this is no big deal when you consider the fact that water is 25 times more conductive than air.

The body does more to release heat than retain it. Typically, you only gain heat through infections or disease. Physical activity may produce heat in a warm atmosphere, but the body works just as quickly to purposely alleviate the heat before it becomes a danger.

Rule of Threes: Surviving 3 Days Without Water

Water is fundamental to our survival. It could take volumes to elucidate all the ways our bodies utilize water. When you find yourself stranded out in the open without water, you must seek a safe source. It is just as important to drink water in sub-freezing temperatures as it is in extreme heat.

Dehydration manifests in innumerable ways, and by the time you find you are thirsty, the damage to the body has already been done.

You can gauge if you are adequately hydrated by checking the color of your pee. The clearer it is, the more hydrated you are. In extreme heat, you can sweat so much out that you will not be able to eliminate any water in your pee.

Treat all water sources you find in the wilderness as suspect due to the potential for the presence of microscopic pathogens. You can filter water, although not all filters will reduce the pathogens to a satisfactory level. Your best results are with at least a 0.2-micron filter.

While it is not possible to completely eliminate pathogens, you can prevent them from having a negative effect on your system by purifying the water. There are chemical methods for this. You can also boil “wild water” to make it safer to drink.

Avoid water that has obvious indications of toxicity such as an absence of vegetation or the presence of dead animals. Use your common sense. Consider your need for water paramount despite your activity level or how hot the environment is.

Rule of Threes: Surviving 3 Weeks Without Food

Human life on earth started in the feast or famine existence of foraging before we reached the industrial age of plenty. Our biology is such that we are designed to survive in times of lean. We can survive without food because our bodies will live off stored energy.

According to medical doctor Alan D. Lieberson, the body will conserve energy by moderating the metabolism. This economical use of energy varies from one person to another, which is why some people can live for longer periods without food. However, our ability to function grows far less efficient the longer we go without sustenance.

Three Essential Macronutrients:


The body intrinsically breaks carbs down into the simple sugars needed both for the brain to function and for energy.


While we say the body can live off itself, without the building blocks for new cell growth, it will be tantamount to cannibalism.


Despite our own fat reserves in the body, it takes much longer to use these. Metabolically, the body tries to save these knowing the critical nature of starvation. Any fats you can consume in the wild will be used for long-term energy.

With just these three macronutrients, the body can continue to function. It is possible to find micronutrients such as Vitamins, calcium and potassium like those found in fruits and vegetables. There is useful information about the edibles you can find and identify easily in an emergency situation.

Bottom Line

Unless we live in the wilderness or are avid trekkers, facing the wild can take us off our guard. Before you find yourself in survival mode, take heed of the Survival Rule of Threes to be prepared for the quick thinking that is needed. Finally, make sure someone is aware of your adventures and your planned return, so they can alert the authorities if you end up among the missing.

Frequently Asked Questions About The Survival Rule Of 3

Q: I can barely hold my breath for three minutes, so how can I survive without air for three minutes?

Technically, your brain can survive for as much as three minutes without air before cell damage occurs. People can hold their breath for three minutes with practice, but it is not likely most people find themselves working on that unless that are swimmers or divers.

The important point is to be aware that being oxygen starved is the most critical rule because without air, you will die.

Q: If there are only three hours a person can live without shelter, what happens when you can’t make one in that time?

The main idea with this rule is to focus on the importance of gaining adequate protection from the elements. All too often, people are surprised by sudden inclement weather. Invariably, they are not wearing the clothing that would provide the warmth they need, or vice versa, the shade in the hot climate that can wipe you out fast.

The point here is to focus on the importance of gaining some barrier to the extremes before the prevailing conditions will harm you physically and prevent you from obtaining sufficient protection.

Q: If we need two quarts of water each day for our health, how can we go three days without water?

Of all the rules, this one about water can be the most confusing probably due to the mistaken precept that we only need water when we are thirsty. I have seen fit and trained people succumb to dehydration rapidly. If you plan to pack or be prepared for anything for the duration, make it your water supply.

It can be hard to lug around gallons, and access to water can be scarce. This makes it important to make water is a priority in your plans for an outing. The location you choose, the condition of your health and your body mass all can have an impact.