Watermelon And Hydration

The watermelon (Citrullus lanatus) is a large, sweet and succulent fruit, native to Africa and has been cultivated since ancient times.1 It is related to other hydrating fruits and vegetables such as cucumber, pumpkin and squash. It has a hard exterior that protects its soft pink flesh, and it is this refreshing pink flesh that is responsible for its hydration properties.

Watermelons are one of the most hydrating foods because they are made up of 92% water, making it a perfect snack to easily hydrate and support your body.2 Staying hydrated is crucial to your well-being in many ways: regulating body temperature, preventing infections, maintaining correct blood pressure, and much more.3 Essentially, hydration is key to our survival, and watermelon can play a role in this.

Nutritional content of watermelons

Watermelon is a low-calorie fruit which mainly consists of water and carbohydrates (including natural sugars) with little protein and fat content.

In a 100g serving of watermelon, the nutritional values are:

  • Calories (energy) – 30 kcal
  • Water – 91.4%
  • Carbohydrates – 7.6% (with 6.2% of this being sugars)
  • Protein – 0.61%
  • Fat – 0.15%
  • Fibre 0.4%

Vitamins and minerals

Like many other fruits, watermelons are a great source of several vitamins and minerals that can improve your well-being. For example, watermelons contain:

  • Vitamin C: An antioxidant that is important for keeping cells healthy, promoting wound healing, and maintaining healthy skin, blood vessels, and bone formation5
  • Vitamin B1: An important mineral for maintaining the nervous system6
  • Vitamin B6: Plays a crucial role in the circulatory system by the body form haemoglobin, which transports oxygen around the body6
  • Potassium and magnesium: Electrolytes that are necessary for maintaining bodily functions such as controlling body fluid levels, building strong bones and teeth, and supporting a healthy cardiovascular system7

Other compounds that are abundant in watermelons


Watermelons are enriched with carotenoids, including beta-carotene, which is needed by the body to produce vitamin A. Vitamin A has several important functions in the body, such as supporting the immune system, integumentary system, and the visual system.8


Watermelons contain a considerable amount of lycopene, which is another type of carotenoid. It is vital to human health because it prevents oxidative damage to DNA, lipids, and proteins. Therefore, lycopene is linked to a reduced risk of various types of cancers because it induces apoptotic cell death.9


An amino acid responsible for the red appearance of the watermelon’s flesh and can be transformed into arginine by the kidneys. Citrulline and arginine are crucial for our health because these compounds can boost immunity and lower blood pressure by producing nitric oxide, which plays a role in relaxing blood vessels.10

Hydration power of watermelon

Due to watermelon’s high-water content, it will not only quench your thirst but also contribute significantly to your daily fluid intake, making it a hydrating powerhouse. According to the British Nutrition Foundation, foods containing more than 80% of water will contribute to your daily intake by providing extra water on top of the 6-8 glasses of fluid we should drink a day.11 As watermelon fits this criterion, your body will thrive from these extra nutrients.

Hydration benefits

We lose water throughout the day through our skin, urine, sweat, and in small amounts when we breathe. Therefore, we need to drink and eat fluids to stay hydrated and maintain the correct functioning of our bodily processes. As watermelon contains plenty of minerals and electrolytes such as calcium, potassium, and magnesium, these minerals are crucial for supporting a healthy body.

Here are a few benefits of keeping hydrated:

1.) Water aids in digestion

Water is necessary to help you digest food because it is needed by saliva to break down food in the mouth. It is also required to digest soluble fibre, which promotes healthy bowel movements by creating soft stools that are easy to pass.

2.) Water helps remove waste

Water enables the removal of waste products such as sweat, urine, and faeces from the body. This is because the organs that are responsible for purification and waste removal such as the kidneys and intestines, use water to flush out waste. Waste must be removed from the body to prevent the build up of toxic materials, which can cause serious harm.

3. Water protects your tissues, spinal cord, and joints

Water keeps your cells and tissues moist, which keeps us alive. Additionally, water plays additional roles in lubricating and protecting your muscles and joints.

What happens when we get dehydrated?

If we do not drink enough fluids, over time, we will become dehydrated. Studies have identified that dehydration has negative effects on our short-term memory, attention, and physical strength.12,13 Therefore, it is vital to ensure that you are drinking enough fluids to prevent these issues from occurring.

Dehydration is most likely to occur in hot weather or during physical activity. When exercising, we need to increase the amount of fluid we take to replace the water loss through sweat. Watermelon makes the perfect rejuvenation snack because, alongside its high water content, it contains lots of sugars and minerals that will help speed up the rehydration process. This is because glucose accelerates the transport of sodium into the body, enabling water and electrolytes to enter the cells faster.14

Can you drink too much water?

Yes, in rare cases, individuals have consumed excessive amounts of water that the body cannot get rid of which causes sodium levels in the blood to become dangerously low.11 This can have serious health consequences. However, eating watermelons in moderation will not contribute towards this issue, so there is no need to panic.

Other watermelon benefits

  • It will satisfy any sweet tooth cravings due to it being full of natural sugars
  • It is good for your heart because watermelon is cholesterol-free, fat-free, sodium-free, and low in calories
  • It is a great snack for all ages! Children and adults love watermelon due to its taste and aesthetic appearance

Other hydrating fruits

If you are not a fan of watermelon, why not try some other hydrating fruits that will count towards your daily water intake:15

  • Yellow melon – 91% water
  • Oranges – 86% water
  • Apples – 86% water
  • Blueberries – 85% water

How to incorporate watermelon into your diet

Watermelon can be eaten as is, simply by cutting the watermelon into slices, making it a great snack to share with friends in the summer. However, if you have plenty of watermelon left over, it can be daunting to include in meals. But fear not, here are a few effortless suggestions:

1.) Watermelon salad: Simply add feta, mint, cucumber, and lime juice for a summery, tangy, and quenching salad that offers the perfect blend of sweet and savoury flavours.

2.) Watermelon daiquiri: This refreshing summer cooler requires only watermelon, white rum, and lime juice mixed together. Serve with garnish and enjoy on a warm summer evening to unwind. For an alcohol-free version, remove the rum and add more lime juice.

3.) Watermelon smoothies: No recipe is necessarily needed- Just add whatever fruits you have available at home. However, I recommend adding lime juice with the watermelon, as the flavours complement each other well. It is a perfect way to reduce food waste!

4.) Snack for a sports match: If you play a team sport, bring sliced watermelon to the game to replenish your lost electrolytes. Your teammates will thank you.


Watermelon should not only be remembered as a summertime snack but also as an essential fruit year-round, responsible for rehydration and replenishing nutrients and vitamins. Its high water content, combined with essential minerals and electrolytes, makes it a great food to eat to maintain optimum hydration levels. The next time you indulge in a juicy watermelon slice, remember that you are not only eating a low-calorie treat but also nourishing your body with the hydration it craves.


  1. Paris HS. Origin and emergence of the sweet dessert watermelon, Citrullus lanatus. Annals of Botany [Internet]. 2015 Aug 1;116(2):133–48. Available from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4512189/
  2. Naz A, Butt MS, Sultan MT, Qayyum MMN, Niaz RS. Watermelon lycopene and allied health claims. eldoradotu-dortmundde [Internet]. 2014 Jun 3 [cited 2023 Nov 23]; Available from: https://eldorado.tu-dortmund.de/handle/2003/33727
  3. Manz F, Wentz A. The Importance of Good Hydration for the Prevention of Chronic Diseases. Nutrition Reviews. 2005 Jun;63:S2–5.
  4. FoodData Central. FoodData Central [Internet]. fdc.nal.usda.gov. 2019. Available from: https://fdc.nal.usda.gov/fdc-app.html#/food-details/167765/nutrients
  5. NHS. Vitamin C - Vitamins and minerals [Internet]. NHS. 2020. Available from: https://www.nhs.uk/conditions/vitamins-and-minerals/vitamin-c/
  6. NHS . B vitamins and folic acid - Vitamins and minerals [Internet]. Nhs. 2020. Available from: https://www.nhs.uk/conditions/vitamins-and-minerals/vitamin-b/
  7. NHS Inform. Vitamins and minerals [Internet]. www.nhsinform.scot. 2020. Available from: https://www.nhsinform.scot/healthy-living/food-and-nutrition/eating-well/vitamins-and-minerals/
  8. NHS Choices. Vitamin A - Vitamins and minerals [Internet]. NHS. 2020. Available from: https://www.nhs.uk/conditions/vitamins-and-minerals/vitamin-a/
  9. ACANLI M, BAŞARAN N, BAŞARAN AA. Lycopene: Is it Beneficial to Human Health as an Antioxidant? The Turkish Journal of Pharmaceutical Sciences. 2017 Nov 20;14(3):311–8.
  10. Ikeda Y, Young LH, Scalia R, Lefer AM. Cardioprotective effects of citrulline in ischemia/reperfusion injury via a non-nitric oxide-mediated mechanism. Methods and Findings in Experimental and Clinical Pharmacology. 2000 Jan 1;22(7):563–3.
  11. British Nutrition Foundation. Hydration - British Nutrition Foundation [Internet]. www.nutrition.org.uk. [cited 2023 Nov 24]. Available from: https://www.nutrition.org.uk/healthy-sustainable-diets/hydration/?level=Consumer#:~:text=Some%20foods%20have%20a%20high
  12. Zhang N, Du SM, Zhang JF, Ma GS. Effects of Dehydration and Rehydration on Cognitive Performance and Mood among Male College Students in Cangzhou, China: A Self-Controlled Trial. International Journal of Environmental Research and Public Health [Internet]. 2019 Jun 1;16(11). Available from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6603652/
  13. Shaheen NA, Alqahtani AA, Assiri H, Alkhodair R, Hussein MA. Public knowledge of dehydration and fluid intake practices: Variation by participants’ characteristics. BMC Public Health. 2018 Dec;18(1):1–8.
  14. Jeukendrup AE. Training the Gut for Athletes. Sports Medicine [Internet]. 2017 Mar;47(S1):101–10. Available from: https://link.springer.com/article/10.1007/s40279-017-0690-6
  15. U.S. Department of Agriculture. FoodData Central [Internet]. Usda.gov. 2019. Available from: https://fdc.nal.usda.gov/
This content is purely informational and isn’t medical guidance. It shouldn’t replace professional medical counsel. Always consult your physician regarding treatment risks and benefits. See our editorial standards for more details.

Get our health newsletter

Get daily health and wellness advice from our medical team.
Your privacy is important to us. Any information you provide to this website may be placed by us on our servers. If you do not agree do not provide the information.

Lavinia de Saram

Bachelors of Science – BSc Biological Sciences, University of Reading

Lavinia is a recent graduate who is delving into the world of medical writing.

Leave a Reply

Your email address will not be published. Required fields are marked *

my.klarity.health presents all health information in line with our terms and conditions. It is essential to understand that the medical information available on our platform is not intended to substitute the relationship between a patient and their physician or doctor, as well as any medical guidance they offer. Always consult with a healthcare professional before making any decisions based on the information found on our website.
Klarity is a citizen-centric health data management platform that enables citizens to securely access, control and share their own health data. Klarity Health Library aims to provide clear and evidence-based health and wellness related informative articles. 
Klarity / Managed Self Ltd
Alum House
5 Alum Chine Road
Westbourne Bournemouth BH4 8DT
VAT Number: 362 5758 74
Company Number: 10696687

Phone Number:

 +44 20 3239 9818