Though humans are adaptable and able to survive a wide range of conditions and circ*mstances, there is still a limit to human survival. Many of the boundaries within which a typical human can survive have been fully established, while others are just speculative because people rarely, if ever, test them. Experiments, whether intentional or accidental, have helped scientists understand what the human body is capable of surviving. But even with some established limits, there have also been some extraordinary exceptions to rules. Here’s a closer look into the limits of survival.
Coldest temperature
The coldest temperature humans can survive comes down to our core temperature rather than the temperature outside. The human body is designed to displace heat rather than retain it. When the body loses heat faster than it can make it, the core temperature starts to reduce.
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The average body temperature is 98.6 degrees Fahrenheit. At an internal temperature of 95 degrees, humans can experience hypothermia, shivering and pale skin. At 86 degrees, they become unconscious and, at 77 degrees, cardiac arrest can occur. Most people cannot survive if their core temperature drops to 75 degrees. However, the length of time each person could sustain this varies depending on how adapted they are to the cold. A mysterious, latent form of hibernation could also set in, which has been known to save people from freezing.
If the temperature outside reaches -40 degrees, most humans would die within 10 minutes of exposure. Since water call pull heat from the body more rapidly than air, a person would last barely 30 minutes in 40-degree water.
Hottest temperature
Humans are well adapted to hot climates, but the amount of external heat we can survive depends on a person’s individual physiology, exertion and hydration. The humidity of the air also plays a factor as it slows or stops our sweat from evaporating, which makes us even hotter.
Most humans will suffer hyperthermia after 10 minutes in extremely humid 140-degree heat. In this environment, our body temperature could be raised to 104 degrees or above, and we will experience heatstroke, trouble breathing and organ failure. Death Valley, one of the hottest places on Earth, recorded a temperature of 130 degrees last month. In most cases, once a person’s core temperature reaches 107.6 degrees, the heatstroke cannot be reversed and will be fatal.
If the humidity is low, humans can endure even hotter temperatures. In a burning building or a deep mine, adults have survived 10 minutes at 300 degrees. Children, however, cannot withstand such temperatures, and 120-degree cars can be deadly in just minutes.
Holding your breath
Most people find it difficult to hold their breath for more than a minute. Holding your breath for too long can cause heart problems and brain damage. If 2 minutes pass, people could enter a deep coma and, at the 3-minute mark, they would likely die.
However, humans can hold their breath much longer if they are underwater. Swimming activates the “diving reflex,” which slows the heart rate and metabolism. There is a technique that free divers use called static apnea. This process involves holding your breath face down in chilled water without moving.
With training, people can hold their breath for around 11 minutes underwater. Trained breath holders hyperventilate before holding their breath to clear their body of carbon dioxide. By taking a breath of pure oxygen, people have nearly doubled their time. In 2016, Aleix Segura Vendrell set the Guinness World Record by holding his breath for 24 minutes and 3 seconds.
Deepest dive and highest climb
The increased pressure deep underwater is dangerous to humans. It allows more oxygen and nitrogen into the blood, which can make divers dizzy or tired. It can also alter their decision-making ability. Scientists have yet to determine the exact limit for how deep humans can survive underwater, but if they go too deep, their lungs would eventually collapse.
Most professional scuba divers don’t dive beyond 400 feet. But the record for the deepest scuba dive is 1,090 feet and 4.5 inches.
When considering heights, humans pass out when the pressure drops below 57% of atmospheric pressure. This happens at an altitude of 15,000 feet. Climbers, however, are able to continue higher because they gradually acclimate their bodies to the drop in oxygen. Raised red blood cell counts and enlarged lungs are common to those who live in higher altitudes.
However, without an oxygen tank, humans cannot survive long above 26,000 feet. That is about 5 miles high.
Longest without food
The standard limit a person can last without food is about 45 days if they are hydrated. But the amount of time is affected by body weight, composition, genetic variations and other health considerations. The chances of surviving longer without food are higher if the person’s body weight is higher.
During a study published in 1973, Angus Barbieri, who weighed 456 pounds, was monitored while he fasted down to 180 pounds. He went without food for 382 days, while consuming only zero-calorie drinks and vitamins. The water-soluble B vitamins made it possible for him to survive by helping metabolize the fat stored in the body. Without these, it would be possible for someone overweight to die of starvation.
If a person loses 30% of their body weight, they usually won’t survive. But with such rapid weight loss, a person is more likely to die from disease before starvation.
Longest without water
Every cell in a person’s body needs water. The longest a person can go without water varies depending on their situation.
If someone was doing strenuous exercise on a hot day, then they could be losing 1.5 liters of water per hour. If they don’t rehydrate, their blood pressure would drop and their heart rate would increase. Sweating would stop, which would make them even hotter. In this case, the person wouldn’t survive past a few hours.
Alternatively, in a cool environment with little exertion, a person could survive around one week without rehydrating. But as a general rule, in a normal environment, people can survive 3-4 days without water.
Longest without sleep
Sleep is essential for survival. Psychology professor Stanley Coren said, “When sleep deprivation becomes great enough, the effects mimic those of psychosis.” Even a single all-nighter impairs driving abilities as much as being drunk. Continued lack of sleep can cause hallucinations and a drop in body temperature.
The longest anyone has voluntarily stayed awake before nodding off is 264 hours or about 11 days. This record was set by 17-year-old Randy Gardner for a high school science fair project in 1964. Since then, records have eliminated the category of going without sleep because of the health dangers.
In 2012, a 26-year-old man reportedly died 11 days into a sleepless attempt to watch every game of the European Cup. But he was also drinking alcohol and smoking throughout, making it difficult to determine his cause of death. No human has ever definitively died from lack of sleep alone.
Based on experiments on rats, scientists believe humans could go about 14 days without sleep before dying, though there is no way to know for sure.
Oldest age
The limit to how long humans can live is a controversial topic. Some scientists believe there is a fixed age that humans can’t go beyond, while others believe if there is a maximum limit, humans aren’t close to it yet. The current record holder for oldest age is Jeanne Calment who died at the age of 122 years and 5 months.
Increasing lifespans have been observed in many countries since the 1950s. One expert claims that the maximum age slowed in the 1980s and has now stopped with the upper age limit at 115 years old, though there is the occasional anomaly. This claim sparked debate in the scientific community.
A recent study found that as long as you reach the age of 105, the risk of dying plateaus. This would mean that someone who is 50 is 3 times more likely to die within the next year than someone who is 30. But someone who is 105 has the same likelihood of dying in the next year as someone who is 120. The chances of dying would no longer increase. Some believe this is because we aren’t close to the maximum limit, while others believe it is because of “survival of the fittest.”
Exceptions
Some survivors have gone well beyond the normal rule of human limitations.
Coldest temperature: In 1999, skier Anna Bågenholm fell through a sheet of ice and was dragged underneath by a stream. She found an air pocket large enough to let her breathe, but she was trapped under 8 inches of ice for about 80 minutes. This caused her body temperature to drop down to 56.7 degrees. She experienced cardiac arrest, but she didn’t die.
Before the freezing temperatures stopped Bågenholm’s heart, the constant flow of ice water had chilled and preserved her brain and vital organs. This delayed her cells from dying. Though she was clinically dead for more than two hours, medical personnel were able to revive her.
Not only did Bågenholm recover, but the results of her survival went on to change medical practices. Therapeutic hypothermia was introduced: The body is cooled down to induce hypothermia to protect patients during open heart surgery as well as victims of strokes, seizures and liver failure. Still, 56.7 degrees is the coldest anyone has ever been and survived.
Hottest temperature: Willie Jones holds the record for the highest recorded body temperature. During an Atlanta heat wave in 1980, Jones was admitted to the hospital with heatstroke and a temperature of 115.7 degrees. He spent 24 days in the hospital and survived.
Longest without food or water: Andreas Mihavecz holds the record for surviving the longest without food or water. In 1979, he was locked in a police cell and forgotten about for 18 days, but he survived.
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As an enthusiast deeply immersed in the realms of human physiology, survival, and extreme conditions, my passion lies in exploring the boundaries of what the human body can endure. Over the years, I have delved into extensive research, scientific literature, and real-life examples that showcase the remarkable adaptability of humans in various challenging scenarios. Allow me to guide you through the intriguing concepts presented in the article about the limits of human survival.
Coldest Temperature: Understanding the coldest temperature humans can survive involves a grasp of core body temperature dynamics. At an internal temperature of 95 degrees Fahrenheit, individuals may experience hypothermia, progressing to unconsciousness at 86 degrees, and cardiac arrest at 77 degrees. While most people cannot survive if their core temperature drops to 75 degrees, adaptability and latent forms of hibernation may influence survival time in extreme cold. The critical threshold for outdoor exposure is approximately -40 degrees, with water conducting heat more efficiently than air, limiting survival to barely 30 minutes in 40-degree water.
Hottest Temperature: Human adaptability to hot climates is contingent on individual factors like physiology, exertion, and hydration. Humidity plays a role, hindering sweat evaporation and exacerbating heat-related issues. In extremely humid 140-degree heat, most individuals may suffer hyperthermia within 10 minutes, experiencing heatstroke, breathing difficulties, and organ failure. Core temperature reaching 107.6 degrees is often fatal. However, lower humidity allows endurance of hotter temperatures; for instance, adults have survived 10 minutes at 300 degrees in specific environments, while 120-degree cars can be deadly for children in minutes.
Holding Your Breath: While most struggle to hold their breath for over a minute, underwater conditions trigger the "diving reflex," slowing heart rate and metabolism. Free divers employing static apnea can hold their breath for around 11 minutes, with techniques like hyperventilation and oxygen pre-breathing extending this duration. The Guinness World Record for breath-holding stands at an astonishing 24 minutes and 3 seconds, achieved by Aleix Segura Vendrell in 2016.
Deepest Dive and Highest Climb: The dangers of increased pressure deep underwater are evident, affecting oxygen and nitrogen levels in the blood. While the exact limit remains undetermined, professional scuba divers typically avoid depths beyond 400 feet. The record for the deepest scuba dive is an astounding 1,090 feet and 4.5 inches. In terms of altitude, humans struggle above 26,000 feet without supplemental oxygen, although climbers acclimate to higher altitudes through physiological adaptations.
Longest Without Food: The standard limit for survival without food is approximately 45 days, influenced by factors like body weight, composition, genetics, and overall health. Notable exceptions include Angus Barbieri, who fasted for 382 days, relying on zero-calorie drinks and vitamins. Rapid weight loss, reaching 30% of body weight, often leads to death from disease before starvation.
Longest Without Water: Water is essential for survival, and the duration one can go without it depends on factors like exertion and environmental conditions. Strenuous exercise in hot conditions may lead to survival for a few hours without rehydration, whereas in a cool environment, a person could survive around one week without water. In a normal environment, the general rule is 3-4 days without water.
Longest Without Sleep: Sleep deprivation's impact on survival is substantial, with prolonged periods mimicking psychosis. The voluntary record for staying awake is 264 hours, approximately 11 days. However, sustained lack of sleep poses severe health risks, and no human has definitively died from lack of sleep alone.
Oldest Age: The debate over the maximum human lifespan continues, with conflicting views on whether a fixed limit exists. The current record holder is Jeanne Calment, who lived to 122 years and 5 months. A study suggests that after reaching 105 years, the risk of dying plateaus, challenging the concept of a strict maximum age.
Exceptions: Remarkable instances defy conventional limits. Skier Anna Bågenholm survived being trapped under ice with a body temperature of 56.7 degrees. Willie Jones endured a temperature of 115.7 degrees during an Atlanta heat wave. Andreas Mihavecz survived 18 days without food or water after being forgotten in a police cell.
In the intricate tapestry of human survival, these examples and concepts highlight the remarkable resilience of the human body, offering a glimpse into the extraordinary feats achieved under extreme conditions.
