Revisiting the Rule of Threes, by J.M.

If you’ve been involved in prepping for any length of time or even just done some research on the subject, you’ve probably come across some variation of the Rule of 3s. I’ve seen it expressed a lot of different ways, but the most common version goes something like this:

  • You can survive 3 minutes without oxygen or with severe bleeding
  • You can survive 3 hours without a stable core body temperature
  • You can survive 3 days without water
  • You can survive 3 weeks without food

The rule makes a great starting point for planning your preparations, but I’ve found that many people tend to take it too literally without really understanding all of the ramifications. I also believe that there are some additional critical elements that should be included, so over the years I’ve expanded it in several areas. The goal of this article is to evaluate what the rule means, some additional realities that apply, and discuss some enhancements that I find useful.

3 Seconds

One of the first enhancements I made to the rule was to add a consideration for ‘rapidly energetic’ events like explosions, roof collapses, earthquakes, shooting events, plane crashes, fatal auto collisions, etc. I phrased it as:

‘You can survive 3 seconds in an energetic event’

In regards to preparing for a ‘3 Second’ event, you may be thinking that the only thing you can do to prepare is to make your peace with God and keep your fingers crossed that it never happens to you. However, as I discussed in my previous article (‘Surviving the Golden Hour’, 2, 3, 4, 5) there are steps you can take to reduce the risk of ever being subject to such an event in the first place. The most obvious one is to avoid areas and situations where such events are more likely to occur as much as possible. Terrorist bombings and mass shootings tend to occur more often in crowded public places and events, serious earthquakes tend to occur in places like California, and fatal car crashes tend to occur when you’re not paying attention when you’re driving. I’m not suggesting that you lock yourself in a remote cabin and never come out, but you should always consider all of the risks when you’re planning any activity that occurs in a location that you’re not 100% familiar with and don’t control, and pay attention to what’s going on around you at all times.

For example, say you’re attending an outdoor Christmas festival downtown in a large city and all of a sudden you notice an increased law enforcement presence, including tactical vehicles showing up on side streets and dog teams walking around. That’s a good sign that the police are expecting serious trouble and that you should vacate the area quickly. Put away your phone when you’re driving and pay attention to what’s going on around you, and try to temper your aggravation at other drivers with the knowledge you’re a lot more likely to avoid an accident if you remain calm. If you’re in the area when an event like a mass shooting does begin, don’t pull out your stupid phone and start filming it – get under cover (versus concealment) or get prone. If you’re in a commercial building and smell gas, get out as quickly as possible. Always evaluate the current and near-future survival situation around you and where you plan to be and consider the risks of any planned activities.

3 Minutes

The standard 3-minute rule says you can survive 3 minutes without oxygen, which includes severe bleeding (since blood is what carries oxygen around your body). However, the average person can only hold their breath for around 30-90 seconds, so if you’re deprived of oxygen or seriously bleeding for longer than that you’ll most likely start getting dizzy and pass out. There are things you can do to increase your lung capacity and subsequently increase the amount of time you can function in an environment where breathing is hard – stop smoking, undertake cardio exercise, practice holding your breath, etc. You should also take training such as ‘Stop the Bleed’ so you’ll be more prepared to deal with serious bleeding wounds.

In terms of kit, you can carry rescue devices like a pocket smoke mask or a SCUBA pony bottle to provide breathing relief in fires or underwater situations. For the bleeding part you should always have a tourniquet or the components to improvise an effective one. I also recommend carrying some hemostatic gauze, compressed gauze and compressed elastic wrap so you can deal with the majority of sever bleeding wounds, including those on the torso where a tourniquet can’t be applied.

While the oxygen and bleeding components aspects are critical, I believe there are two other aspects of preparedness that are important in terms of minutes – state of mind and the ability to extricate yourself from emergency situations. The first aspect is that you may not survive three minutes in a disaster emergency if you don’t have the right frame of mind, meaning you panic or don’t react at all. Panic is a result of the ‘fight or flight’ reflex that’s hardwired into every human being, and will typically result in people blindly rushing towards whatever appears to be safety and away from what appears to be danger, regardless of the actual situation. While panic affects different people in different ways, there are some common approaches you can take to reduce the chances of panicking during an emergency:

  • Teach yourself to think critically about situations and avoid reacting (or not reacting) emotionally or following a ‘herd’ mentality. For example, if you’re in a large building and the fire alarm goes off, don’t assume it’s just a drill or test just because everyone else does. Evaluate your risk and act appropriately – if you’re on the first floor and next to an emergency exit you can probably afford the time to evaluate the situation further before taking action. However, if you’re on the 15th floor you should probably start heading down the emergency exit stairs pretty quickly.
  • Think about and plan for different emergency scenarios in your head whenever you go somewhere, and participate in emergency drills if they’re available. Studies have shown that you’re a lot less likely to panic if you have thought about and planned for an emergency scenario beforehand.

The opposite end of the emergency reaction spectrum is to do nothing, either because of a ‘freeze’ reflex or engaging in something like normalcy bias. The freeze reflex is a natural reaction to a situation where your subconscious mind quickly determine you can neither successfully fight or flee from danger, so you freeze up as kind of a last-ditch effort to survive, hoping the danger will pass you by. Normalcy bias is a tendency to dismiss a danger as real or significant, and as a result take no action to protect yourself from it. Minimizing the risk of freezing up or engaging in normalcy bias requires the same preparations as addressing panic – get in the habit of critically analyzing everything going on around you, and think about various scenarios in your head so you have at least the starting point of a response plan if something does happen.

Hand-in-hand with having the right mindset is having the knowledge and ability to quickly extricate yourself from emergency or disaster situations. If you enter a building do you know where all of the possible exits (including windows, loading docks, etc.) are and where the closest one is? Do you know where the closest cover is in case someone starts shooting? Are you in good enough physical condition to quickly get to the exit, get down the emergency stairs and get out of the building? Can you move quickly enough and for long enough to escape a moving wildfire? When minutes make the difference between dying and surviving, knowing how to quickly extricate yourself from a dangerous situation can save your life.

3 Hours

The standard 3-hour rule focuses on the need for a stable core body temperature in order for you to continue to function effectively. Most people tend to focus on staying warm in cold situations, but staying cool in hotter environments is just as critical. The average core body temperature is around 98.6F – if that drops below around 95F you’ll start shivering and your skin will start turning pale, which is the beginning of hypothermia. At a core temperature of around 86F most people become unconscious, and if you hit 77F a cardiac arrest is likely. (Hypothermia.) On the other end of the spectrum, if your core temperature starts rising above 104F you’ll start experiencing dizziness, fatigue, heatstroke, organ failure and eventually death. (Hyperthermia.) The common ways to address the 3-hour rule are to make sure you’re always dressed appropriately, you’re in good health, and have some kit like emergency mylar blankets and fire-starting capabilities with you in colder weather. In hotter weather the same appropriate clothing rule applies, you should plan for frequent breaks in the shade and take steps to make sure you’re equipped to move around at night when it’s cooler.

Extending the 3-hour rule, I would add that it’s the time period where having a plan starts to become critical. In many slower-evolving disaster scenarios such as the beginning of major civil unrest, societal breakdown, declaration or martial law, rising flood waters, spreading fires, developing severe weather, etc., how you react in the first few hours may ultimately determine if you survive. If you don’t know how to respond or where to go and your approach is: “I’ll wait for the government to tell me what to do”, then you pretty much deserve whatever you get. Whereas ‘3-minute’ situational awareness involves knowing where things like the closest exits and cover are, ‘3-hour’ planning involves knowing where you are, both in terms of immediate surroundings as well as in terms of broader geography, what’s going on and what your best options are for ensuring your survival. This might be identifying nearby secure locations to hunker down and ride out the immediate event, or having multiple possible travel routes mapped out to start your journey home. Kit for supporting a plan might include documented get-home plans, maps, digital maps and GPS on your mobile device, etc.

Hand in hand with having a plan is having the information necessary to make appropriate decisions on executing or adapting that plan. For example, say you’re visiting some friends at a location that’s several days walk from your house and there’s a massive broad-based cyberattack that takes down a large part of the nation’s infrastructure, resulting in major chaos across the country. You have a plan and maps for getting home, but the most direct route takes you near a large manufacturing plant that produces chemicals. If the attack caused an explosion at the plant and released huge clouds of toxic chemicals you probably want to take a different route, but how can you determine that?

Or say you’re visiting a customer site near a large city when massive ‘mostly peaceful’ riots break out and you need to get home to protect your family – what routes are safe for you to take, and when is the safest time to travel? Having some kit like a handheld scanner radio to listen to weather reports, police and emergency activity, etc. can provide critical information, some good maps with potential hazards marked out can allow you to plan alternate routes, a decent monocular or set of binoculars can allow you to check out your line of march for potential problems before they can impact you, and having a small mirror can allow you to peek around corners and out of windows without exposing yourself to danger. Having current information can be critical to surviving the first few hours following any disaster.

3 Days

The standard rule says you can survive 3 days without water, but depending on your condition, level of activity and the environment you’ll probably start experiencing the symptoms of dehydration after only a day or so without anything to drink. These symptoms can include fatigue, dizziness, confusion, headaches, disorientation and cramps – conditions that are not conducive to survival. Unless you’re operating in an area where clear, pure, disinfected water is readily available for your entire trip, you’ll need some kit to ensure you can obtain and transport what you need. Common pieces of a water kit include a filter, one or more soft water bottles for transport, and potentially a sillcock key for obtaining water from building stand pipes or faucets. You could also use techniques such as boiling, water purification tablets or solar disinfection to purify drinking water.

Besides needing water, another requirement that will kick in after a day or so is the need for sleep. While people can typically function for several days without sleep, your ability to function effectively will start dropping off after around 24 hours, and you’ll start experiencing symptoms like inability to focus, reduced decision-making ability and reduced physical coordination.

In a recent article on SurvivalBlog I discussed sleep planning in detail, but it still remains one area that many people tend to not plan for. The need for sleep has a unique aspect – it’s the one bodily condition your body can actually force you to provide. If you’re tired enough and you sit down for even a minute, there’s a good chance you’ll fall asleep right where you are, which may not be the best location in terms of survival. Plan on stopping for at least 6-8 hours every day and make sure you have the necessary kit and a safe location for getting a good night’s sleep in current environmental conditions.

3 Weeks

The standard rule says you can survive 3 weeks without food, but once again, depending on your physical condition, level of activity and environment, you’ll start experiencing symptoms after only a few days. These symptoms may initially manifest as fatigue and dizziness, and will escalate to reduced physical capability, reduced cold tolerance, and fainting. If you’re planning on surviving any sort of physical activity such as walking for more than 1-2 days you need to include some provision for either packing or acquiring food.

A week or so after an event is also when mental health may start becoming an issue, especially if you’re traveling to get home. Continued exposure to various hardships will begin to wear on you, and your sense of urgency will probably begin to dull after days of trying to get home. This is when you’ll need to dig deep to find the strength to carry on and overcome the mental roadblocks that will start to appear. Regular activities such as reading the Bible, meditation, and reflecting on your family and friends can help you keep your focus in the face of adversity. The critical thing to keep in mind is that as long as you’re alive, there’s always hope.


To summarize, here is my expanded Rule of 3s:

You can survive…

3 Seconds

  • Caught in an energetic event

3 Minutes

  • Without oxygen or with severe bleeding
  • Without the right mindset
  • Without the knowledge and ability to extricate

3 Hours

  • Without a stable core body temperature
  • Without a plan
  • Without relevant information

3 Days

  • Without water
  • Without sleep

3 Weeks

  • Without food
  • Without the right mental attitude

My goal here was to expand the standard rule of 3’s to include additional areas I felt were important to survival. Not every factor will be relevant for every type of disaster or emergency scenario, but understanding and planning for all of them can significantly increase your overall odds of survival.