But what really happens to your body when you become dehydrated? What are the symptoms? At Watery, we've put together this post to address these important questions—and to share our top tips on how to stay hydrated and avoid dehydration in the future!
What is Dehydration?
Your body is made up of 45-75% water (depending on gender, age, and body size). Dehydration occurs when you don’t consume enough water, causing your body’s water levels to drop too low. Whether you’re young or old, an athlete or not, maintaining fluid balance is essential for your brain and body to function at their best. And for athletes, it’s critical for top performance! Your fluid balance depends on how much fluid you take in through food and drink versus how much you lose through urine, sweat, and other processes.
How Does Dehydration Affect Your Performance?
Even mild dehydration can noticeably reduce your performance. Mentally, it lowers your concentration, making it harder to focus on your technique, process goals, or deliver powerful fly kicks in competition. Just a 2% loss of body weight from fluid—about 1-1.5L—can cut your performance by up to 20% (!!), according to studies.
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- Does that mean you need to drink 60L of water a day to avoid dehydration and perform at your best? Absolutely not. You should drink when you feel thirsty—and ideally before you even feel that thirst. Remember, you also gain fluids from your meals, since food contains water too. And keep in mind that overloading on water before activity can just mean extra (unnecessary) weight to carry or swim with!
Signs of Dehydration
Unless you’re training in intense heat or your body is severely low on fluids, you may not always notice when you’re dehydrated. There are various degrees of dehydration based on your fluid deficit, so early detection is key. These quick checks can help if you suspect you might be running low on fluids:
- Urine color. Fluid balance often shows in your urine’s color. A good rule of thumb: your urine should be the pale yellow of diluted elderflower juice. It shouldn’t have a strong odor, either. Dark, strong-smelling urine means your body has less fluid for kidney filtration, so waste is more concentrated—a classic sign of dehydration.
- Skin elasticity. Dehydration also affects how elastic your skin is. Try the Turgor test: pinch the skin on the back of your hand between your thumb and forefinger, then let go. Well-hydrated skin snaps back instantly. If it takes longer to return to normal (feeling almost like soft rubber), you may be dehydrated. Dry, irritated skin is another sign.
- Muscle cramps. It’s true—if you don’t drink enough, your muscles can cramp up. Muscles are mostly made of water (and, of course, protein!). With insufficient hydration, those “soft” muscles tighten and contract, causing cramps.
- Concentration. Since your brain is mostly water, dehydration often leads to sluggishness, fatigue, headaches, and irritability.
If you notice these symptoms (and they're not dangerously severe), the likely cause is fluid deficiency. The best remedy: rest, hydrate thoroughly, and consider an electrolyte supplement if needed.
Can Dehydration Cause Illness?
Yes, it can! When you’re dehydrated, your body’s mucous membranes dry out. These membranes contain antibodies that fight off bacteria and viruses you’re exposed to via your airways (and any other entry points). When they dry out, your risk of infections—like coughs and sore throats—increases.
If you take diuretic medication, your fluid needs are even higher!
Dehydration can also disrupt your sleep (and its quality), which is vital for proper recovery. On the flip side, drinking too much before bedtime can mean frequent nighttime trips to the bathroom, which can be disruptive too.
How to Prevent Dehydration!
The best solution is to prevent dehydration before it starts. Drink enough water—tailored to your environment, body size, and activity level. As a swimmer, it’s easy to underestimate fluid loss from sweat during sessions because it gets mixed with pool water, so it’s especially important to stay proactive.
If you’re always well-hydrated, you can avoid fluid deficits entirely. However, overdoing water intake can upset your body's salt balance, which is just as important. A healthy, varied diet usually supplies enough salts, but during intense training or camps, your salt levels might need extra support. That’s where electrolytes come in—and at Watery, we recommend tasty, high-quality options from purepower!
Hydro Tabs
Hydro Tabs from purepower are electrolytes in capsule form. Each tube contains 20 tablets (4g each), with only electrolytes and NO added sugar or carbs. They taste like blueberry (think sparkling water – Blue Keld style!). One tablet dissolves easily in water, helping you maintain optimal fluid balance—plus, they’re tasty and travel-friendly!
A tube of 20 tablets costs 74.95 kr at
Carbo Race Electrolyte
This product, unlike Hydro Tabs, comes as a powdered drink mix. Carbo Race Electrolyte delivers both carbohydrates and electrolytes, which is ideal for longer and tougher training sessions where energy dips are a risk. As a long-distance swimmer, I rely on this delicious, mild orange juice-flavored drink—proudly made and tested in Denmark! For each session, I mix 60g of powder with 650ml of water.
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My Personal Experience
Earlier in this article, I mentioned experiencing dehydration myself at a summer training camp. I first noticed it during a morning practice: fatigue and nausea under the blazing sun, where temperatures easily topped 30°C from 9 to 11am.
I was sent back to my hotel room for the best remedy: sleep and plenty of water. Three hours later—post-lunch—I felt ready to get back in action (at least, I thought so!).
Mistakes like this are valuable opportunities to reflect and improve. Despite being diligent with my carbs and electrolytes at every session—and balancing sour, salty, and sweet foods at meals—I had to figure out what went wrong.
The answer was surprisingly simple: I only drank fluids during active periods—meals, training, pool time, stretching—but never during siesta or afternoon naps. Ironically, those are the times when the body recovers and prepares for your next session—making hydration even more crucial!
In the days that followed, I focused on drinking plenty of fluids before meals (which, by the way, also curbed my appetite). The difference was clear: my mood lifted, and my muscles felt less sore—meaning better recovery and improved performance overall!
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What I’m Taking Forward
The biggest takeaway? Your body needs fluids 24/7. As an athlete, you’re always “on”—and every little choice, including staying hydrated, impacts your performance.
As a side note, hydration matters just as much during indoor training, where high temperatures can sneak up fast!
I hope this helped you understand dehydration a bit better—or at least learn from my missteps! From all of us at Watery, have a fantastic weekend!