Why hydration matters more than you think
My very first role in performance nutrition focused on hydration in athletes. It was there that I learnt hydration is one of the most powerful foundations of both physical and mental performance. Yet it’s something many of us only think about once we’re already thirsty.
The reality is that dehydration exists on a spectrum. Many people associate dehydration with extreme illness or heat exhaustion, but in reality, a large proportion of adults spend much of their day mildly dehydrated—the point at which you’re starting to feel thirsty.
And that matters.
Research shows that even mild dehydration can impair mood, concentration, memory and alertness, making everyday tasks feel harder than they need to.
As both a women’s health dietitian and performance nutritionist, I genuinely believe hydration is one of the most overlooked tools we have to support our health. And you certainly don’t have to be an elite athlete to benefit.
Almost every chemical reaction in your body takes place in a water-based (aqueous) environment. If you want your body to perform at its best—whether that’s thinking clearly, managing your appetite, exercising, or simply getting through a busy day with good energy—hydration needs to be part of the equation.
Should you rely on thirst?
In short—not really.
Thirst is a helpful signal, but it isn’t always an early one. By the time you feel thirsty, you’re already mildly dehydrated. Rather than waiting for thirst to remind you to drink, it’s better to stay slightly ahead of the curve by sipping fluids consistently throughout the day instead of trying to catch up later.
This becomes even more important as we get older. Our thirst response naturally becomes less sensitive with age, and women going through perimenopause and menopause may be at greater risk still. Falling oestrogen levels can make thirst signals less reliable while also increasing fluid losses through hot flushes and night sweats, making it easier to become dehydrated without even realising it.
One of the simplest ways to check your hydration status is to look at your urine:
- Pale straw colour: You’re well hydrated.
- Dark yellow or amber: Time to drink.
- Completely clear: You may be drinking more than you need. While this isn’t usually something to worry about, aiming for pale straw-coloured urine is a better target than crystal clear.
The signs of dehydration
Dehydration simply means you’re losing more fluid than you’re replacing. It exists on a spectrum, from mild dehydration through to heat exhaustion and, in severe cases, heat stroke
Mild dehydration which occurs around 1–3% fluid loss can affect both how you feel and how you function. Common signs include feeling thirsty, a dry or “cotton wool” mouth, headaches, darker urine, fatigue, irritability, reduced concentration and a noticeable dip in physical performance. Research also shows that even mild dehydration can impair mood, memory and alertness, making everyday tasks feel harder than they need to.
As dehydration progresses, your body has to work much harder to regulate its temperature. and this can lead to heat exhaustion or moderate dehydration. In addition to the symptoms above, you may develop heavy sweating, dizziness or light-headedness, a rapid heart rate, muscle cramps, weakness, lethargy and nausea. Heat exhaustion is your body’s way of telling you it is struggling to cool itself and needs rest, shade and fluids.
Heat stroke is the most severe form of heat-related illness and requires immediate medical attention. Symptoms include confusion or disorientation, collapse or loss of consciousness, a very high body temperature and, unlike heat exhaustion, you may stop sweating despite being dangerously overheated. Heat stroke can develop rapidly and cause serious damage to the brain and other vital organs if not treated immediately.
How much should you drink?
Around 20% of our daily fluid intake comes from food, particularly fruit, vegetables, soups, stews and dairy foods. Some of the most hydrating foods include cucumber, lettuce, tomatoes, watermelon, strawberries, oranges and Greek yoghurt.
For most adults, 1.5–2 litres of fluid per day is a sensible starting point. You’ll likely need more if you’re physically active, spending time in hot weather or naturally sweat more. Rather than aiming for a perfect number, think of this as a guide and learn to respond to your body’s needs and the colour of your urine!
Four simple ways to make hydration effortless
1. Build it into your routine. The easiest habits are the ones you don’t have to think about.
Treat hydration like brushing your teeth—something that’s simply part of your day. Carry a water bottle you know the size of so you can keep track of how much you’re drinking rather than relying on endless glasses you’ll lose count of.
2. Drink steadily throughout the day. Spacing your fluids out is far more effective than drinking large amounts in one go. Aim to meet most of your fluid needs before the evening. If you’re drinking litres before bed, you’re likely to pay for it with disrupted sleep and middle-of-the-night trips to the bathroom.
3. Make water more interesting. If plain water feels boring, change the experience.
Add slices of lemon, orange or cucumber, fresh mint or berries. Herbal teas and other caffeine-free drinks all contribute towards your daily fluid intake, and if you dislike the taste of tap water, a filtered jug may make all the difference.
4. Train your bladder. If you feel like you’re constantly running to the toilet, don’t panic—your bladder can adapt. Often it’s simply become used to emptying at very low volumes. Gradually delaying visits by a few minutes can help retrain your bladder, with the aim of comfortably going every two to four hours. Pair this with regular pelvic floor exercises to improve bladder control and reduce the risk of incontinence, particularly during midlife.
Common hydration myths
Myth 1: Coffee and tea are dehydrating.
Not true. Although caffeine has a mild diuretic effect, the fluid in tea and coffee more than offsets this, meaning they still contribute towards your daily hydration.
Myth 2: Everyone needs exactly eight glasses of water a day.
Fluid requirements vary depending on your size, activity levels, the weather and your overall health. Use general recommendations as a guide rather than a strict rule.
Myth 3: If you’re not thirsty, you’re hydrated.
Not necessarily. Thirst becomes less reliable as we age and during the menopause transition, so relying on thirst alone may mean you’re already mildly dehydrated.
Your Hydration Checklist
✔ Start your day with a glass of water before your first coffee or tea.
✔ Carry one water bottle you know the size of and keep track of refills.
✔ Aim for around 1.5–2 litres of fluid each day, adjusting upwards if you’re exercising, it’s hot or you sweat heavily.
✔ Drink most of your fluids earlier in the day to protect your sleep.
✔ Add fruit, herbs or herbal teas if plain water feels boring.
✔ Check your urine colour—pale straw is the goal.
✔ Pair a glass of water with each meal to support hydration and help with fullness.
Dr Linia Patel PhD, RD, MBDA (@liniapatelnutrition) is the author of Life After Weight Loss Medication & Food For Menopause, and an award-winning women’s health dietitian, performance nutritionist and public health researcher
