Hydration for Health: Why Drinking Enough Water Daily Is More Important Than You Might Think

1 February 2026

Many of us don’t realise how quickly dehydration can affect us. Being just 1–2% dehydrated can reduce concentration, increase fatigue and make both physical and mental tasks feel harder, often before thirst kicks in.

Water does more to our body than just helping us perform or think better. Almost all biological processes require water. So, while water and hydration might seem like a boring topic, there are a few things all of us should be aware of so that we don’t end up hurting our body.

Highlights

Water is essential for almost all bodily functions.
According to the NHS good hydration guide, adults should drink 1.5 to 2 litres of fluid daily.
Nearly 75% of Brits drink less than 1000 mL of water per day.
Adequate hydration may help improve certain medical conditions, and dehydration may worsen some conditions.

Did you know a 2024 UK Fitness Report found that an average Brit drinks only about 700 mL water a day. This amount is less than half of the NHS’ daily recommendation.

What Is Hydration?

Hydration refers to consuming water from foods and beverages. All people should maintain appropriate daily hydration status based on their gender, age, level of physical activity, and environmental conditions.

Water is undeniably the most important nutrient; its absence can turn fatal within a few days. It comprises 70% to 80% of soft tissues in our body, and 45% to 70% of the total body weight. (1,2)

Our body needs water for almost all biological processes that sustain life. Some of the key functions of water include: (3)

Regulation of body temperature
Keeping tissues in the eyes, nose and mouth moist
Protection of body organs and tissues
Delivery of nutrients and oxygen to cells
Lubrication of joints
Supporting kidneys and liver by removing waste products
Dissolving minerals and nutrients so that our body can access and use them

Importance of hydration

Staying hydrated helps our body maintain the health of every cell in the body.

Moreover, taking enough water daily means our body has enough bloodstream liquid to flow through blood vessels. When we are dehydrated, particularly during exercise or in hot environments, our blood volume decreases and blood viscosity increases.

These effects are typically transient and unlikely to cause any serious issues in an otherwise healthy person. However, in certain people, they may strain the kidneys, elevate blood pressure, and increase the risk of clots.

Water is also crucial to:

Making saliva and maintaining oral health. Dehydration contributes to lower salivary output, increasing the risk of dental diseases.
Support digestion and help prevent constipation.
Keep the skin moist and improve its appearance.
Improve memory and mood.

How Much Water Do We Need Daily?

According to the NHS good hydration guide, (4)

Adults should drink 1.5 to 2 litres of fluid daily.
Children should drink 1.2 to 1.6 litres of fluid daily.

Certain people may need to drink more water daily, such as pregnant or breastfeeding women, those living in hot environments, or those recovering from illness.

How to Stay Hydrated Appropriately

Drink water or fluids regularly throughout the day. Consider drinking about 200 mL every waking hour.
You may drink more fluids right after waking up and gradually decrease the intake as the day progresses.
For adults, semi-skimmed, 1% fat or skimmed milk and unsweetened plant-based drinks count as healthy fluids.
Avoid drinking more than 150 mL of fruit juice and smoothies a day. To avoid sugar spikes, drink them with a meal.
Drink additional fluids if you’ve been sweating from exercise, or if you’re ill.
Limit caffeine, alcohol, and sugar drinks.
Sparkling water or lime water can be a healthy option for those who don’t like the taste of water.

Also Read: How Does Alcohol Affect Vitamin Absorption and Energy

What Happens If We Don’t Drink Enough?

If we don’t drink enough water or fluid, we may experience many unwanted effects, such as:

Low energy
Mental fog
Moodiness
Overeating
Slowed metabolism
Headaches
Skin damage
Decreased strength, power, and endurance

Dehydration and Symptoms

Dehydration occurs when we lose more fluids than we replace. Untreated dehydration can be dangerous, especially among children and older adults.

Drinking less does not immediately lead to dehydration. However, in certain situations, our body loses excessive water in a short period of time, which we may not be able to replace. This is when things can get worse.

When we are dehydrated, the deficit in body water is high enough to disrupt normal bodily functions. Dehydration is more likely to occur in people who:

Have diabetes, diarrhea, or been in the sun for too long.
Have drunk large amounts of alcohol.
Have a fever or too much sweating during or after exercising.
Use medications that increase urine output (water pills).

Symptoms of dehydration

In adults and children, dehydration symptoms can include:

Excessive thirst
Dark yellow, strong-smelling pee
Decreased urinary frequency
Dizziness or lightheadedness
Lethargy
Dry mouth, lips and tongue
Sunken eyes

Dehydrated babies may have sunken eyes, few or no tears while crying, and fewer wet nappies. They may also become unusually irritable or drowsy.

Hydration and Disease: Can Drinking Too Little Fluids Affect Disease Conditions?

While it’s well established that hydration status affects nearly all bodily functions, its link with specific diseases is a bit complicated. In the following sections, we will discuss how hydration can affect specific disease conditions.

Staying hydrated may benefit people with: (5)

Kidney stones
Constipation
Urinary tract infection (UTI)
High blood pressure
Gallstones
Dental disease
Glaucoma (increased pressure in the eye that can damage optic nerve and cause blindness)

Short-term dehydration may contribute to complications associated with:

Prolonged labor
Cystic fibrosis
Kidney damage due to accumulation of toxins like certain medications, heavy metals, and solvents
Exercise-induced narrowing of the airway

Even moderate dehydration can increase heart rate and reduce the amount of blood pumped by the heart. Studies show that water losses as little as 2% of body weight can reduce strength by 2%, power by 3%, and endurance by 10%. (6)

Hydration and disc health

There’s no direct evidence that dehydration accelerates disc degeneration. The major drivers of disc desiccation and resultant degeneration are aging, diabetes, obesity, oxidative stress, and poor nutrition in the disc structures.

However, animal study shows that drinking too little water lowers lumbar disc water content. The dehydrated discs are stiffer and less flexible. (7) So good hydration is probably supportive but insufficient to prevent or reverse structural disc desiccation.

Further Reading: What Is The Role of Type II Collagen In Degenerative Disc Disease And How Do Collagen Supplements Help

Hydration and gout

Gout is a form of arthritis that causes severe joint pain. When we have high levels of uric acid in our blood, urate crystals can form around the joints, causing pain.

Dehydration can increase the levels of uric acid in the blood, which may trigger a gout attack. Studies show that drinking enough fluid starting 24 hours before a gout flare can significantly reduce recurrent gout attacks. (8)

According to a 2022 study, people who have gout should consider drinking water enough to keep daily urine output above 2000ml. (9)

Hydration and skin

Water keeps our skin moist and helps maintain the integrity of the skin barrier function. On the other hand, dehydration can make the skin rough, scaly, and itchy.

Adequate water intake, especially among the elderly or obese, can dramatically improve skin softness, smoothness, and appearance. (10,11)

Hydration and fall risk

Dehydration can impair balance, coordination, and muscle strength, probably increasing the risk of falls and related injuries. (12)

Replacing Water With Sugary Drinks Is A Bad Idea

Children and adolescents often prefer the sweet taste rather than the taste of water. (13)

Moreover, most of them believe that the cooling sensation associated with sugary drinks quenches their thirst better. This can lead them to (partially) replace their water intake with sugary drinks, which can worsen dehydration.

Sugary drinks often have high amounts of sugar, caffeine, and other ingredients that can cause our kidneys to produce more urine.

According to a Scientific Advisory Committee on Nutrition (SACN) report, sugary drinks are a key contributor to overweight or obesity in children and adults in the UK. In children between 4 and 10 years, soft drinks and fruit juice contribute to 30% of the total daily sugars from the diet. (14)

In the UK, food manufacturers use different terms to describe free sugar on the food label, such as:

Cane sugar
Honey
Brown sugar
High fructose corn syrup
Fruit juice concentrate
Corn syrup
Fructose
Sucrose
Glucose
Nectars
Crystalline sucrose

Sugary drinks include carbonated soft drinks, fruit drinks/juice, sports/energy drinks, and sugared coffee/tea drinks.

Frequently Asked Questions

Do you need 8 glasses of water a day?

Most people should aim to drink about 8 glasses of water a day. This amount equals to 1600 mL of water or fluids.

Do tea and coffee dehydrate you?

Both tea and coffee contain caffeine, which is a mild diuretic. However, moderate tea or coffee consumption is unlikely to cause dehydration as the water present in the cup will typically compensate for the water loss caused by caffeine.

Can you drink too much water?

Yes, it’s possible to drink too much water. Drinking too much water may, in rare cases, can lead to hyponatremia, a potentially life-threatening condition caused by too little sodium in the bloodstream.

What are top water-rich foods to add to the diet?

The top water-rich foods to add to the diet include:

Cucumber
Tomatoes
Spinach
Mushrooms
Yellow melon
Broccoli
Brussel sprouts
Oranges
Apples
Blueberries

Key Takeaways

Hydration supports circulation, temperature control, digestion, kidney function, and brain performance. Even mild dehydration can affect energy levels, concentration, and physical performance.

The best way to maintain hydration is to drink enough water and fluids as recommended by the government guidelines. We may need to increase our water intake under certain conditions, like high temperatures, high levels of physical activity, and age/gender.

References:

Hartley, Naomi A, and Susan L Thibeault. “Systemic hydration: relating science to clinical practice in vocal health.” Journal of voice : official journal of the Voice Foundation vol. 28,5 (2014): 652.e1-652.e20. doi:10.1016/j.jvoice.2014.01.007
Seol, Jung Eun et al. “Effect of Amount of Daily Water Intake and Use of Moisturizer on Skin Barrier Function in Healthy Female Participants.” Annals of dermatology vol. 36,3 (2024): 145-150. doi:10.5021/ad.23.067
Mahowald, Allie, RDN. “Water: Essential for Your Body.” Mayo Clinic Health System, 29 Sept. 2022, www.mayoclinichealthsystem.org/hometown-health/speaking-of-health/water-essential-to-your-body-video
“Good Hydration Guide.” Aneurin Bevan University Health Board, abuhb.nhs.wales/news/news/good-hydration-guide.
Manz, Friedrich. “Hydration and disease.” Journal of the American College of Nutrition vol. 26,5 Suppl (2007): 535S-541S. doi:10.1080/07315724.2007.10719655
Judelson, D.A., Maresh, C.M., Anderson, J.M. et al. Hydration and Muscular Performance. Sports Med 37, 907–921 (2007). https://doi.org/10.2165/00007256-200737100-00006
Han S-M, Lee S-Y, Cho M-H, Lee J-K. Disc hydration measured by magnetic resonance imaging in relation to its compressive stiffness in rat models. Proceedings of the Institution of Mechanical Engineers, Part H: Journal of Engineering in Medicine. 2001;215(5):497-501. doi:10.1243/0954411011536091
Kakutani-Hatayama, Miki et al. “Nonpharmacological Management of Gout and Hyperuricemia: Hints for Better Lifestyle.” American journal of lifestyle medicine vol. 11,4 321-329. 2 Sep. 2015, doi:10.1177/1559827615601973
Mei, Yongsheng et al. “Excess Uric Acid Induces Gouty Nephropathy Through Crystal Formation: A Review of Recent Insights.” Frontiers in endocrinology vol. 13 911968. 14 Jul. 2022, doi:10.3389/fendo.2022.911968
Palma, Lídia et al. “Dietary water affects human skin hydration and biomechanics.” Clinical, cosmetic and investigational dermatology vol. 8 413-21. 3 Aug. 2015, doi:10.2147/CCID.S86822
Mac-Mary, S et al. “Assessment of effects of an additional dietary natural mineral water uptake on skin hydration in healthy subjects by dynamic barrier function measurements and clinic scoring.” Skin research and technology : official journal of International Society for Bioengineering and the Skin (ISBS) [and] International Society for Digital Imaging of Skin (ISDIS) [and] International Society for Skin Imaging (ISSI) vol. 12,3 (2006): 199-205. doi:10.1111/j.0909-752X.2006.00160.x
Khorami, Fatemeh, et al. “Investigating the Impact of Dehydration and Hydration on In-Vivo Hip Soft Tissue Biomechanics.” PLoS ONE, vol. 20, no. 8, Aug. 2025, p. e0328054, doi:10.1371/journal.pone.0328054.
Johnson, Richard J., et al. “Current Hydration Habits: The Disregarded Factor for the Development of Renal and Cardiometabolic Diseases.” Nutrients, vol. 14, no. 10, 15 May 2022, article 2070, doi:10.3390/nu14102070.
Public Health England. “PHE urges parents to cut sugary drinks from children’s diets.” GOV.UK, 17 July 2015, www.gov.uk/government/news/phe-urges-parents-to-cut-sugary-drinks-from-childrens-diets