The four basic necessities of life refer to the items that are required for an individual to survive and sustain life. You may feel mere discomfort with the temporary lack of one or more of these necessities, but prolonged deficiency can drastically affect life to the point where the body ceases to function properly and dies.
Air is a necessity for all living things. Animals, humans and plants all need oxygen to sustain life. Without it, your body cannot function; it will shut down and eventually die. Air quality should be considered as well. Fresh mountain air will be cleaner and have fewer pollutants than the air near a freeway that is filled with vehicle emissions and other airborne toxins.
Our bodies are mostly made up of water. If you do not take in enough water, your cells cannot function properly. It is recommended that humans consume eight to 10 glasses of water daily to maintain optimal health. More water may be needed if you have suffered moderate to severe bleeding, are sick, have been exercising or live in very hot climates. You need water to digest your food and absorb the nutrients.
If you get dehydrated, your bodily functions will be negatively affected. It puts a strain on your heart as it tries to pump cells that are inadequately hydrated through the heart chambers. Signs of dehydration are irrational behavior, delusions and visual hallucinations. If you are in an emergency situation, you should seek water before food.
The food you eat breaks down to be used as fuel for your body. If you do not consume calories to be converted into energy, your cells will start to shut down. You can live several days without food, as long as you have water. If you are not getting an adequate food intake, you may experience irritability, fatigue, depression, lack of concentration and apathy.
Shelter can mean a couple of things. Shelter in general means protection from the elements, but it usually is a structure, such as a house, building or tent. If you go without shelter, you can suffer hypothermia, dehydration or heat stroke in extreme weather conditions. Clothing is considered a personal shelter that helps regulate and sustain body temperature.