People have some very essential survival needs and if one of them isn’t met, then a person’s life will be endangered. We all know we can’t live without food, water, sleep, oxygen and shelter for very long. Some of these we can live without for a month or two, but some other (like oxygen) we can’t live without for more than several minutes. We know that, with training, people can manage to extend these limits but you should never try to experiment yourself with any of them.
Checking for how long you can survive without water, sleep or food is not a game and shouldn’t be treated as such! You can potentially hurt vital organs and this may even lead to irreversible damages.
Still, it is important to have a general idea on how long you can live without food and water if you’re in the wilderness and probably in a critical situation. As long as you’re prepared with this information you could apply that knowledge successfully and survive harsh times. In general, here is how long, on average, you can survive without:
- Food – 1-2 months
- Water – 3-7 days
- Sleep – 11 days maximum
How long can you live without food?
If you’re deprived of nutrition you can still survive long enough for you to find a way to provide yourself with food. It may take up to a few months before your body can’t sustain itself on your fat storage. There have been recorded strikes, when people went on hunger strikes and most of them managed to live up to 70 days without any food. Most of them died before the strike was over.
Anyways, this is a general number and usually the period varies greatly from person to person. There are several factors, which determine how long a particular individual can survive without food like weight, genetic predisposition, etc. Another very important factor for increasing your chances of living more than the average time without food, is hydration. The better hydrated you are, the longer you can survive without food and nutrition.
A very popular example of this is Gandhi, who (while on a hunger strike for the independence of his country) survived 21 days while simply drinking enough water. It is known, that water cleanses the body from toxins and removes plaques from the liver and arteries.
During starvation, the body has to sustain itself only on what nutrient stores it has. For example, for a body to remove successfully toxins from the liver, it needs sufficient amount of certain nutrients. By using them, the liver can break down toxins and neutralizes them. They pass through the body without harming it.
If you starve for days and weeks, and you don’t take enough water, then these toxins will not only be broken down much harder, but also, the liver won’t be able to remove them, without the presence of enough water in the body. Water helps the metabolism and the removal of toxins. It is known that people who when on harsh diets and for longer near-starvation periods, have developed irreversible illnesses, due to the inability of the liver to process toxins. If the body is overall healthy, and it has stored enough nutrients, it can handle the detoxification process well.
This is the reason why, dehydration may shorten the individual’s survival while it’s starving. The first stages of starvation begin in the body’s metabolic state. The body begins using its own fat stores, which while burning out produce energy for the organism to keep having enough strength to search for food (in evolutionary terms).
After a few days (2-3 days), another process will start – this is the ketone stage. This means that the body will begin burning the fat reserves in the liver. If there is fat in other organs, they will also be used up by the body. These fatty acids from the liver are called ketones.
The next stage may start to actually damage the body. If the individual is still starving and all fat reserves are used up entirely, the body will turn to itself. The body will literally begin eating itself, by using tissues from the intestinal walls, muscles, and other organs.
The longer this process goes on, without interrupting the starvation, the lower the chances for repairing these damages. They may be permanent if the person starves for longer than 3-4 weeks. One of the most dangerous damages may occur to the heart muscles. As the body starts destroying the heart muscles, it will become weaker and weaker and won’t be able to pump enough blood to the other organs. As a result, it may just shut down and death will occur.
This process will last for about 1 month on average, but as you can see, it depends on the body. For example, if a person has more fat reserves, that person may survive longer than 1 month. A person with very few fat reserves may not survive even a month. Also, the strength of the body and the immune system are also indicative factors for longer survival rates. In addition to that, if the muscles are in good shape and the person is strong, they have also better chances for surviving longer than 1-1,5 months.
How long can you live without water?
The survival rate in this category is much lower than with starvation. As we already mentioned, water is the main source for purifying and detoxifying the body. Without water, the liver will fail within fewer than 3 days. If the liver is in bad shape, the individual may not even have 2-3 days. In extreme cases, when the person doesn’t exert himself/herself too much, that person can survive for up to 7 days. These cases are usually rare and they require very calming conditions, so that the person doesn’t lose too much water fluids.
If a person is out in the wilderness, they may not have such perfect conditions. In the wild, a person may survive for 3 (max 4) days. This is because, they would probably search for water, and this means, losing energy and sweating (losing water much faster). This is true for any season, so it’s not only about summer hiking/trekking. During the winter, the body may lose water even faster, since it requires water to keep the body’s temperature at a normal state. If the person is dehydrated, they lose warmth much quicker and this may risk their life.
It has been calculated that at temperatures above 80 degrees F, an average person can survive for up tp 7 days. As you add 5 more degrees, the lifespan shortens with an entire day. If, as we mentioned, you move and exert yourself more, you weaken your body and dehydration will kick in much sooner.
A short explanation of what water does to the body will also help determine which processes will be impaired during dehydration. We already mentioned the detoxification and flushing of toxins and heavy metals. Also, many bodily functions need water to maintain the overall health.
Examples are flushing impurities through urine and sweat. Also, the body loses water through sheer breathing. Also, if it’s very hot and you’re overexerting, the body will lose fluids too quickly and if you don’t replenish that lost water, your body will keep heating inside. As we know, proper hydration keeps the body cool and maintains normal body temperature. This happens through sweat. If the body has lost lots of fluid and it can’t sweat any more, your body will overheat and the internal organs will be damaged very quickly.
The heart though will shut down much quicker than you expect. In severe hot conditions and overexertion an average person can’t survive for more than several hours.
You also need to know that water keeps the joints well hydrated, and keeps them in good shape. If the water content in the joints decrease, they will become painful and even swollen. Another issue with the lack of water, is that, without water your body can’t digest food. Since the stomach needs water (and hydrochloric acid) to make the stomach acid, it may not be able to produce it without sufficient water from the body’s stores. In addition to that, you won’t even be able to chew the food, since saliva is also formed by water (and enzymes).
In order for you to evaluate properly the dehydration process you need to know the different stages and detailed processes that occur in the body. If for example you’re dehydrated with 2-3%, this would mean that your blood has thickened to almost 20%. This would mean that the blood’s volume has diminished, it’s thicker and as a result it circulates within the body much slower and inefficiently.
It would take much more time for the blood to oxygenate certain more distant part of the body like the fingers and limbs. As a result, you would first feel your hands and feet colder than usual, and even if it’s warm outside, you’d still start to feel cold.
What’s making it worse though isn’t just the general feeling of being cold. Some capillaries are thinner (e.g. those in the brain) and the thicker blood will not be able to go through these capillaries. The brain will enter an oxygen deficiency state and you may start hallucinating. You will also lose your sense of orientation and consciousness. Some people will even lose consciousness in extreme stages of dehydration.
In the first stage of dehydration you will experience symptoms like dry mouth (lack of saliva), peeing much rarely and much less. On top of that the urine’s color will be dark yellow to dark orange and will have unpleasant odor. The next stage, moderate dehydration, you’ll urinate even more rarely and the amount will be decreased significantly. Your eyes will feel dry and slightly swollen. You will feel tired and your heartbeat will be unnaturally rapid.
With the advanced stage of dehydration (severe dehydration) you will no longer urinate. Lethargy will hit in. You will be extremely tired and irritable. You will start vomiting, thus dehydrating even faster, plus diarrhea will hit in and in the final stages you will basically suffer from shock, your skin will turn to bluish gray color and will be very cold. Your blood pressure will decrease significantly, which is the reason why the body will turn cold and the skin extremely pale.
So, overall, you have to be a very healthy person, not exerting yourself at all and remain in average temperature warmth to be able to survive for up to 6-7 days. But as these conditions seem too regulated and unnatural, you may not have that much time. As we mentioned, if you’re in the wilderness, searching for water, you have on average 3 days.
How long can you live without sleep?
Determining how long a person can live without sleep is much harder than with food and water. The sleep pattern and the body’s own response to lack of sleep are what makes it hard to say how long you can survive without sleep. Actually, the record of a person who was able to stay awake without using any stimulants is 11 days or 264 hours.
Sleep deprivation is a very serious problem and people have died from this. For instance, there is the case of a Chinese man who went on watching the European cup for up to 11 days – he was found dead in his apartment. It was discovered that he was also drinking alcoholic beverages, which may have resulted in him dying sooner than he may have lasted if he didn’t drink alcohol.
It is still not clear what makes the body need sleep and why less than 6 hours a day can deteriorate the health throughout the individual’s life. It’s been estimated that people who sleep 6 hours or less in 24 hours, have a significantly shorter life-span.
Let’s see what happens to the body’s functions throughout the sleep deprivation period:
- In the first 24 hours an average person would usually suffer from headaches.
- After 72 hours, the individual will begin losing orientation and will start having cognitive problems and loss of memory.
- As the person continues to suffer from sleep deprivation, after 144 hours the person will start hallucinating and will have little control over their action.
- Even after the first 24 hours the immune system will weaken with up to 50%, which makes the organism vulnerable to illnesses, flues, infections, etc.
It is important to note that during sleep DNA is being repaired and damaged cells are replaced with new cells. This means that the body needs to regenerate and enter a passive (more like hibernation) state, so that any damage that has occurred during the active part of the day, has been repaired.
Not only that, but the body also enter a state of high stress. This is because the body is sleep deprived and the mental capacity of concentration is significantly reduced. Stress hormones are released in the blood stream and the blood pressure rises. This easily can cause heart attacks, especially with older people or people of fragile health.
Another interesting thing to mention is that there have been made experiments with laboratory rats. They have been kept awake by slight electrocution every time they begin to sleep (and before they enter a REM mode). With time, their metabolism started to speed up and they usually enter a hyper-metabolic state, which weakens their bodies even further. Hyper-metabolism has been linked to sleep deprivation. As the body enters such a state, the organism will begin functioning much faster, and even if it’s in a rest, the metabolism remains unnaturally high.
The organism burns nutrients and fat stores much quicker for it to be able to replenish the stores. The body is much more prone to infections and it will have much lower chances for fighting infections, since the immune system is so weak, that it can’t even fight an ordinary flu. This process occurs with people too.
While there are cases when people have survived for very long periods of sleep deprivation, this doesn’t mean that everyone can survive it. The usual average individual (including animals) can’t survive for more than a month.
Sleep deprivation itself doesn’t lead to irreversible conditions since it doesn’t tend to damage organs like dehydration and starvation. This doesn’t mean that anyone should attempt or experiment with sleep deprivation to see how they can manage.
Some people have done so and didn’t know this may have a fatal end for them. So, experimenting with your body’s limits may damage and compromise your health and isn’t something you should test. If you ever decide to test your limits, you should be constantly supervised by a medical person and your health monitored at all times.