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In survival, the rule of threes involves the priorities in order to survive. [1] [2] [3] The rule, depending on the place where one lives, may allow people to effectively prepare for emergencies [4] and determine decision-making in case of injury or danger posed by the environment. [1]
Normally, the rule of threes contains the following:
Each line assumes that the one(s) before it are met. For example, if you have a large quantity of food and water yet are exposed to the environment, then the harsh conditions rule applies. The rule may sometimes be useful in determining the order of priority when in a life-threatening situation, and is a generalization (or rule of thumb), not scientifically accurate. [5]
Additional generalizations may be presented with the rule, though they are not considered part of the "Rule of threes" and are also usually not scientifically accurate. For example, it might be said that it takes a three-second psychological reaction time to make a decision during an emergency, [1] that you can survive 3 minutes in icy water, [5] or that an individual can last three months without hope (or companionship). [6] [5] [7]
The amount of time a person can survive without a source of water (including food which contains water) depends on the individual and the temperature. As temperature increases, so does water loss, decreasing the amount of time a person can survive without water. The longest anyone has ever survived without water was 18 days. [8] The source of the "3 days" number likely comes from an experiment two scientists did in 1944 where they ate only dry food for a period of time; one ended the experiment at 3 days in, and the other at 4 days in. However since they stopped the experiment before being in any real danger, the actual survival time at room temperature likely exceeds 3-4 days. [8] However, at temperatures greater than room temperature, dehydration can occur very quickly, and death can occur in a matter of hours rather than days. In these cases people typically die of heat stroke first, not terminal dehydration. [8] One person was purported to survive 7 days in the desert, 6 of these without water, without suffering heat stroke as the temperature reached no higher than 103.2 °F (39.6 °C) during his ordeal. [9] However, he had reached the third stage of dehydration, which is 80-90% fatal; this likely represents an upper limit of survival at high temperatures. [9]
Hypothermia is defined as a body core temperature below 35.0 °C (95.0 °F) in humans. Symptoms depend on the temperature. In mild hypothermia, there is shivering and mental confusion. In moderate hypothermia, shivering stops and confusion increases. In severe hypothermia, there may be hallucinations and paradoxical undressing, in which a person removes their clothing, as well as an increased risk of the heart stopping.
Survivalism is a social movement of individuals or groups who proactively prepare for emergencies, such as natural disasters, and other disasters causing disruption to social order caused by political or economic crises. Preparations may anticipate short-term scenarios or long-term, on scales ranging from personal adversity, to local disruption of services, to international or global catastrophe. There is no bright line dividing general emergency preparedness from prepping in the form of survivalism, but a qualitative distinction is often recognized whereby preppers/survivalists prepare especially extensively because they have higher estimations of the risk of catastrophes happening. Nonetheless, prepping can be as limited as preparing for a personal emergency, or it can be as extensive as a personal identity or collective identity with a devoted lifestyle.
Supercooling, also known as undercooling, is the process of lowering the temperature of a liquid below its freezing point without it becoming a solid. Per the established international definition, supercooling means ‘cooling a substance below the normal freezing point without solidification’ While it can be achieved by different physical means, the postponed solidification is most often due to the absence of seed crystals or nuclei around which a crystal structure can form. The supercooling of water can be achieved without any special techniques other than chemical demineralization, down to −48.3 °C (−54.9 °F). Supercooled water can occur naturally, for example in the atmosphere, animals or plants.
Food storage is a way of decreasing the variability of the food supply in the face of natural, inevitable variability. It allows food to be eaten for some time after harvest rather than solely immediately. It is both a traditional domestic skill and, in the form of food logistics, an important industrial and commercial activity. Food preservation, storage, and transport, including timely delivery to consumers, are important to food security, especially for the majority of people throughout the world who rely on others to produce their food.
Survival skills are techniques used to sustain life in any type of natural environment or built environment. These techniques are meant to provide basic necessities for human life, including water, food, and shelter. Survival skills also support proper knowledge and interactions with animals and plants to promote the sustaining of life over time.
Desert warfare is warfare in deserts or similar arid or semi-arid environments. The term encompasses military operations affected by the terrain, climate, and resource availability of these areas, as well as the strategies and tactics used by military forces in these situations and environments.
Desert ecology is the study of interactions between both biotic and abiotic components of desert environments. A desert ecosystem is defined by interactions between organisms, the climate in which they live, and any other non-living influences on the habitat. Deserts are arid regions that are generally associated with warm temperatures; however, cold deserts also exist. Deserts can be found in every continent, with the largest deserts located in Antarctica, the Arctic, Northern Africa, and the Middle East.
A survival kit is a package of basic tools and supplies prepared as an aid to survival in an emergency. Civil and military aircraft, lifeboats, and spacecraft are equipped with survival kits.
Heat syncope is fainting or dizziness as a result of overheating. It is a type of heat illness. The basic symptom of heat syncope is fainting, with or without mental confusion. Heat syncope is caused by peripheral vessel dilation, resulting in diminished blood flow to the brain and dehydration.
Emergency rations are items of food and drink that a person stores and relies on in case of an emergency. Emergency food supplies can be purchased for camping trips or wilderness adventures. These supplies are meant to last for several days. Many people also purchase long shelf life emergency food in case of natural disasters or other emergency situations. The food can come in the form of a powder, freeze dried, smoked or salted. The rations are to help people survive until help arrives and are often carried while hill walking or mountaineering, because of the risk of being stranded by an accident. In some organised events, such as Ten Tors, it is obligatory to carry emergency rations.
Outdoor recreation, such as hiking, camping, canoeing, cycling, or skiing, entails risks, even if participants do not recklessly place themselves in harm's way. In some circumstances, such as being in remote locations or in extreme weather conditions, even a minor accident may create a dangerous situation that requires survival skills. However, with correct precautions, even fairly adventurous outdoor recreation can be enjoyable and safe.
Hiking equipment is the equipment taken on outdoor walking trips. The duration, distance, planned activities, and environment impacts equipment selection. For example, a short day hike across flat farmland versus trekking in the Himalayas would call for different types of equipment.
A food dehydrator is a device that removes moisture from food to aid in its preservation. Food drying is a method of preserving fruit, vegetables and meats that has been practiced since antiquity.
An extreme environment is a habitat that is considered very hard to survive in due to its considerably extreme conditions such as temperature, accessibility to different energy sources or under high pressure. For an area to be considered an extreme environment, it must contain certain conditions and aspects that are considered very hard for other life forms to survive. Pressure conditions may be extremely high or low; high or low content of oxygen or carbon dioxide in the atmosphere; high levels of radiation, acidity, or alkalinity; absence of water; water containing a high concentration of salt; the presence of sulphur, petroleum, and other toxic substances.
Desiccation tolerance refers to the ability of an organism to withstand or endure extreme dryness, or drought-like conditions. Plants and animals living in arid or periodically arid environments such as temporary streams or ponds may face the challenge of desiccation, therefore physiological or behavioral adaptations to withstand these periods are necessary to ensure survival. In particular, insects occupy a wide range of ecologically diverse niches and, so, exhibit a variety of strategies to avoid desiccation.
Camping food is food brought on or designed for camping, hiking, and backpacking trips. The term also encompasses ingredients that can be used to make said foods. The primary differences relate to campers' and backpackers' special needs for foods that have appropriate cooking time, perishability, weight, and nutritional content. To address these needs, camping food is often made up of freeze-dried, dehydrated, pre-cooked, pre-prepared, or otherwise preserved foods that can last extended periods.
Breeding for drought resistance is the process of breeding plants with the goal of reducing the impact of dehydration on plant growth.
BIOPAN is a multi-user research program by the European Space Agency (ESA) designed to investigate the effect of the space environment on biological material. The experiments in BIOPAN are exposed to solar and cosmic radiation, the space vacuum and weightlessness, or a selection thereof. Optionally, the experiment temperature can be stabilized. BIOPAN hosts astrobiology, radiobiology and materials science experiments.
Occupational heat stress is the net load to which a worker is exposed from the combined contributions of metabolic heat, environmental factors, and clothing worn, which results in an increase in heat storage in the body. Heat stress can result in heat-related illnesses, such as heat stroke, hyperthermia, heat exhaustion, heat cramps, heat rashes, and chronic kidney disease (CKD). Although heat exhaustion is less severe, heat stroke is a medical emergency and requires emergency treatment, which if not provided, can lead to death.
Cold and heat adaptations in humans are a part of the broad adaptability of Homo sapiens. Adaptations in humans can be physiological, genetic, or cultural, which allow people to live in a wide variety of climates. There has been a great deal of research done on developmental adjustment, acclimatization, and cultural practices, but less research on genetic adaptations to colder and hotter temperatures.