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How Long Can A Person Survive Without Water?

How Long Can A Person Survive Without Water?

Now there’s an interesting question. A person cannot live long without water.(6) Having sufficient water is essential to our survival.(6) The human body needs to drink sufficient amount of water every day in order to function optimally. The body needs to continuously replenish the fluids it loses every day due to urination and sweat.

Without the intake of a healthy amount of water, you will not live long. You can only survive for a couple of days without water. Furthermore, you will also become more susceptible to dehydration sooner, but this depends on many factors.

How Long Can A Person Survive Without Water?

Why Does The Time Period Vary Regarding Human Survival Without Water?

The number of days a person can go without having water varies from person to person and also on when dehydration sets in. Dehydration is the proper medical term that is used to describe a condition of not having sufficient water in the body to function properly. Everyone needs a certain amount of water every day to maintain their health because water amounts for 60 percent of your body weight. In children, water actually makes up for 75 percent of their body weight,(6) which is why keeping children well hydrated is even more important.(1)

No human being can survive too long without water, though the exact number of days a person can live without water varies from person to person. This is primarily because there are many factors that contribute to the rate at which your body uses water and also how much water. Some of these factors include:

  • Your activity level.
  • Environmental conditions.
  • Your age and overall health.
  • Weight.
  • Food intake.
  • Gender.

The above-mentioned factors contribute to the manner in which your body uses the water. For example, on a hot summer’s day, your body tends to sweat more, thus consuming more water is imperative. Similarly, if you have a high fever or have diarrhea or vomiting, then you will be losing more water. Your body will also need more water when you are exercising.

Certain foods you consume also have an impact on your body’s water levels. Some foods contain more water in them than others and at the same time, your body also gets water from the various beverages you drink during the day, such as juice and herbal teas. However, there are also certain beverages, such as alcohol and caffeinated beverages that can contribute to dehydration.

A study by the Institut für Rechtsmedizin des Universitätsklinikums Hamburg-Eppendorf published in the Archiv Fur Kriminologie found that a human being cannot survive for more than 8 to 21 days without water and food. People who are near death or who are already on their deathbed and are using very little energy will live only for a couple of days or a few weeks without water and food.(2)

It may surprise you to know that water is, in fact, far more essential for the body when compared to food. It has been found that people who carry out hunger strikes without consuming food, but having regular water, can go on to survive for a couple of months or even longer without food but with water.(3)

According to an article published in the British Medical Journal, it is recommended that people who are engaging in a hunger strike, drink 1.5 liters of water every day in order to maintain their fluid levels. The article further recommends adding about half a teaspoon of salt to the water each day in order to replace any sodium that is being lost through sweating.(4)

Water consumption is crucial to your health and according to the recommendations of the Institute of Medicine of the National Academies, men should be getting at least 125 ounces of water per day from both food and drinks, while women should be getting around 91 ounces of water. This recommended average of water intake is for those who are not very active, living in a moderate to a mild climate and are in good health.(5)

The Physiology Behind What Happens When You Don’t Drink Water:

You can think of it being sort of like your body’s sixth sense – your body is always extremely attuned to the amount of water you drink. Based on your level of thirst, it is likely that you are getting sufficient water. When you do not get enough water, though, there will be specific changes in your body. First of all, the cells in your body will start to shrink without sufficient water and your brain will start sending signals to the body to urinate less in order to conserve what little water is left inside. This process occurs through the kidneys as they are the organs that the body relies on for having an adequate water intake in order to function properly.

When you do not have sufficient water, your kidneys start using more energy and eventually start wearing down the tissue. Your kidneys have to function adequately enough in order to flush out the waste from your bloodstream. Over a period of time, your kidneys will eventually stop to function at all without the adequate water intake. At the same time, other organs of your body will also stop functioning.

Lack of water is also going to have an effect on other functions of your body and without sufficient water available, the following can occur:

  • Your body temperature will not be regulated.
  • Your brain may start to swell.
  • Electrolytes in the body become unbalanced.
  • Your joints will not be able to work properly.
  • Your blood pressure may go down or increase.

What is the Role of Food Consumption in Regards to Water Intake?

The fact is that your body does not only receive the proper hydration from all the beverages you are having, including water. Food also has a role to play in your hydration. In fact, food consumption contributes to roughly 20 percent of a human being’s total water intake in a day.(5)

Actually, people who consume a significant amount of fruits and vegetables are able to get even more water from their food when compared to other beverages. For example, people in countries like South Korea and Greece include many more foods that are high in water content in their day-to-day diets, thus resulting in a high water intake through food rather than beverages.(1)

Some of these fruits and vegetables that are high in water content include:

  • Celery(7)
  • Lettuce(7)
  • Watermelon(7)
  • Strawberries(7)
  • Cantaloupe(7)
  • Cabbage(7)

Other foods that also contain a very high level of water include:

  • Chicken breast
  • Salmon
  • Shrimp
  • Yogurt
  • Cottage cheese
  • Pasta

So, consuming foods that are high in water content will also help you prevent dehydration. However, keep in mind that food alone is not likely to provide you with an adequate amount of water that is needed to sustain your body in the long run.

Complications & Side Effects of Not Having Enough Water

When you don’t have enough water, you are at risk of dehydration. Some of the risks and side effects of dehydration include: tiredness, lack of energy, heatstroke or heat cramps, brain swelling, kidney or organ failure, hypovolemic shock, seizures and death.(8)

You need to be careful with your fluid consumption if you are dehydrated. This is because the right method of rehydration varies from person to person. So, while adults just need to drink plain water to get rehydrated, small children, on the other hand, may need to drink a beverage that has sodium apart from water to rehydrate their body. This solution also needs to be taken in very small amounts, to begin with in pediatric cases.

In cases of being severely dehydrated, you might need intravenous administration of fluids.


Maintaining a sufficient amount of water in the body is essential for life. Without water, a human being can only survive for a couple of days. Typically, your level of thirst is a pretty good indicator of how much water you need to be drinking. Also keep in mind that if you live in a hot climate, if you exercise vigorously, or if you suffer from a medical condition (even diarrhea or vomiting), then you need to increase your intake of water to remain healthy. If you suspect that you might be dehydrated, you must contact your doctor at once.


  1. Popkin, B.M., D’Anci, K.E. and Rosenberg, I.H., 2010. Water, hydration, and health. Nutrition reviews, 68(8), pp.439-458.
  2. Kottusch, P., Tillmann, M. and Püschel, K., 2009. Survival time without food and drink. Archiv fur Kriminologie, 224(5-6), pp.184-191.
  3. Obesity Panacea. (2019). The Science of Starvation: How long can humans survive without food or water? | Obesity Panacea. [online] Available at: https://blogs.plos.org/obesitypanacea/2011/05/13/the-science-of-starvation-how-long-can-humans-survive-without-food-or-water/ [Accessed 18 Apr. 2019].
  4. Peel, M., 1997. Hunger strikes: Understanding the underlying physiology will help doctors provide proper advice.
  5. www8.nationalacademies.org. (2019). Report Sets Dietary Intake Levels for Water, Salt, and Potassium To Maintain Health and Reduce Chronic Disease Risk. [online] Available at: http://www8.nationalacademies.org/onpinews/newsitem.aspx?RecordID=10925 [Accessed 18 Apr. 2019].
  6. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2908954/
  7. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2908954/table/T1/
  8. https://newsnetwork.mayoclinic.org/discussion/dehydration-can-lead-to-serious-complications/

Also Read:

Pramod Kerkar, M.D., FFARCSI, DA
Pramod Kerkar, M.D., FFARCSI, DA
Written, Edited or Reviewed By: Pramod Kerkar, M.D., FFARCSI, DA Pain Assist Inc. This article does not provide medical advice. See disclaimer
Last Modified On:January 8, 2020

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