Air Air is our most fundamental need. About three minutes is how long the average person can survive without air.
Water Most people can’t survive more than 4 days without water. Levels of activity as well as heat can shorten survival time.
Food Although there are people who have gone without food for longer periods of time, three weeks without food seems to be the survivable limit for most people.
Temperature Control—clothing and shelter Too much heat or too much cold (or drastic swings in temperature) can be deadly. Aside from cultural values and fashion expectations for being clothed, clothes help us regulate body temperature. I can’t imagine going outside when temperatures are below freezing without a heavy coat and several layers. In a similar “fashion,” shelter helps regulate temperature by providing a buffer to climate outside.
Sleep It is not clear how long a person can survive without sleep. The documented record is eleven consecutive days without sleep. However after 24-36 hours of sleep deprivation, bodily functions begin to alter and people may experience everything from memory problems to hallucinations.
