Survival Basics

Survival Basics: Rule of 3

During real survival situations it is imperative that you know, and apply, the four levels of the rule of 3. Whether you’re a pro or an amateur the rule of 3 is an essential.

The rule of 3 prioritizes the fundamental needs of the human body in ranking order:

  1. Air
  2. Shelter
  3. Water and Food

Air: You can survive 3 minutes without air (oxygen).
Shelter: You can survive 3 hours without shelter.
Water & Food: You can survive 3 days without water (as long as you have shelter) and 3 weeks without food (as long as you have shelter and water)


It seems pretty obvious that the rule of 3 will help you survive no matter the situation. The first order of business when faced with a true survival situation is to make sure you are getting enough oxygen. Next, be sure to ensure you have somewhere to protect you from the elements. Thirdly, water is your priority. The body can only survive 3 days without it. Food is the last necessity as you are able to live for up to 3 whole weeks without it. The most important part of this rule of 3 is that you need to focus on the most basic necessity first. Oxygen is always your top priority.

You Can Only Survive for Three Minutes Without Air

Anyone who suffers from asthma or has had a severe allergic reaction knows how slow time may feel when you are without oxygen. Any situation where your oxygen supply is threatened is definitely a survival situation. This also applies to choking. If someone is truly choking and their oxygen supply is restricted it is imperative that you regain air flow as soon as possible. Whether this means cracking a rib or performing a tracheotomy, air flow must be restored within 3 minutes. Knowing how to perform CPR or The Heimlich Maneuver could mean saving a life. Both these life saving procedures can be learned by taking a certified course or be self-taught.


You may be thinking that this is a situation you’ll likely never find yourself in, however, nearly 8,000 people die in the U.S. each year from lack of oxygen. These statistics include choking, asthma, and allergic reactions

You Can Only Survive for Three Hours Without Shelter

When we think of this statistic we should be mindful that we are discussing exposure to the elements. Of course if it’s a beautiful day and mild temperatures these numbers will change slightly. However, imagine you are climbing a mountain’s peak and are at 9,000 feet. The wind is blowing and the snow is whipping against your skin. Now imagine you’ve been backpacking through an arid region. The sand and dust beneath your feet are burning your flesh. Your skin is peeling from the sun and the sweat is pouring into your eyes. These are situations when exposure to the elements can, and will, play a huge role in your survival. Often, without shelter to shield you from extreme temperatures, rain, or even wind you will be at a much greater risk. This also includes being able to build a fire. This is why it is a main priority to build some sort of shelter. Having the proper shelter will also impact how much water you will be losing through sweat and elimination. This leads to the following rule.

You Can Only Survive for Three Days Without Water and for Three Weeks Without Food

Dehydration happens fairly quickly, however, individuals can have various tolerance levels. Dehydration starts with feeling thirsty and probably pretty sluggish but by the second day the body begins to feel extreme thirst and fatigue and eventually, by the third day, leads to organ failure. Again, everyone is different and this may happen at a slightly different rate but eventually lack of water will lead to your body shutting down and death. Water is needed for basically every bodily process and this is why it is so important. Regulating body temperature, digestion, lubricating joints, hormone regulation, toxin transfer, eliminating waste, and delivering oxygen are just some of the processes that require water. Without proper hydration the body is completely unable to function properly and will stop working. With proper shelter you will last approximately three days without water, however, it’s important to note that exposure to the elements can impact these timetables. Again, if you are stranded in extreme heat this may be a quicker process than if you were somewhere with more mild temperatures.

There are various factors that can impact the exact length of time you can survive without food (such as age, what shape you’re in, if you are properly hydrated etc.). On average it is three weeks. Carbs are the first thing to be used up once you stop eating. Lack of carbohydrates will in turn make you exhausted, sluggish, and lack energy. Next the fat begins to be used. This helps explain why people who may be overweight might be able to survive a bit longer than someone with less fat on their body. Proteins are the next to go, which are essential for the body itself. Once you start to starve your body you will begin to see quite a few symptoms such as weakness, irritability, confusion, diarrhea, and poor decision making. This is because the body relies on food to help aid its many processes.

The moral of the story is that these statistics – the rule of 3 – is absolutely imperative for your survival. Knowing these simple rules can mean the different between life and death.

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