Dehydration is the most common medical issue at outdoor summer events in the UK. Every year, festival and concert medical tents treat hundreds of people who underestimated how much water they needed, or who simply forgot to drink while they were having fun.
The tricky thing about dehydration is that by the time you feel thirsty, you are already dehydrated. And the symptoms of moderate dehydration, headache, tiredness, dizziness, and irritability, are easily mistaken for being hungover, tired from a late night, or just having a bad day.
Here is how to stay properly hydrated at summer events.
How much water do you actually need?
The NHS recommends six to eight glasses of water a day (approximately 1.5 to 2 litres) under normal conditions. At an outdoor event in warm weather, you need significantly more, especially if you are:
- Standing or walking for extended periods
- Dancing
- In direct sunlight
- Drinking alcohol (which causes your body to lose water)
- Eating salty food (which increases thirst)
A practical target for a day at an outdoor summer event is 2 to 3 litres of water, or roughly a 500ml bottle every one to two hours. On very hot days (above 25 degrees Celsius), or if you are very active, you may need more.
You do not need to drink it all in huge gulps. Regular small sips throughout the day are more effective than downing a litre at once, which your body cannot absorb quickly and which mostly passes straight through.
Warning signs of dehydration
Learn to recognise these signs in yourself and in the people you are with:
Mild dehydration
- Thirst (the most obvious sign, but often ignored)
- Dark yellow urine (your urine should be pale straw-coloured when you are well hydrated)
- Slight headache
- Feeling a bit tired or sluggish
- Dry mouth and lips
Moderate dehydration
- Persistent headache that does not improve with paracetamol
- Dizziness, especially when standing up
- Reduced urine output (not needing the toilet for several hours)
- Muscle cramps
- Feeling lightheaded or faint
- Difficulty concentrating
Severe dehydration (seek medical help immediately)
- Confusion or disorientation
- Rapid heartbeat
- Sunken eyes
- Not urinating at all
- Fainting or collapse
- Skin that does not spring back when pinched (a sign of significant fluid loss)
Severe dehydration is a medical emergency. If someone is showing these signs, get them to the event medical tent or call 999 immediately.
Practical hydration strategies
Bring a reusable water bottle
This is the simplest and most effective step. A 750ml to 1-litre reusable bottle that you keep with you and refill throughout the day. Most UK festivals and outdoor events now provide free water refill points, so you do not need to buy bottled water. Fill up every time you pass a tap or refill station.
Clip it to your bag or belt loop so it is always accessible. If you have to rummage through a bag to get your water, you will drink less often.
Start hydrated
Drink a good amount of water before you leave home or your campsite in the morning. Starting the day well hydrated means you are not playing catch-up from the start. Two large glasses of water with breakfast is a good baseline.
Set reminders
It sounds silly, but when you are engrossed in a performance, hours can pass without drinking anything. Set an alarm on your phone every hour as a reminder to take a drink. After a few events, it becomes a habit.
Eat water-rich foods
Fruit, salads, and water-rich snacks contribute to your fluid intake. Watermelon, oranges, grapes, and cucumber all have high water content. Bringing some fruit as festival snacks doubles as a hydration boost.
Understand the role of electrolytes
When you sweat, you lose not just water but also electrolytes, primarily sodium, potassium, and magnesium. If you are sweating heavily, drinking plain water alone may not be enough to fully rehydrate you. Adding an electrolyte sachet or tablet to your water replaces what you lose through sweat.
Electrolyte tablets and sachets are available cheaply from pharmacies and supermarkets. Brands like Dioralyte, High5, and SiS are widely available. They dissolve in water and add a mild flavour while providing the salts your body needs. One or two servings across a hot day is sufficient for most people.
Alternatively, a salty snack (crisps, pretzels, salted nuts) alongside your water achieves a similar effect, though less precisely.
Hydration and alcohol
Alcohol is a diuretic, which means it causes your body to produce more urine and therefore lose more water. For every pint of beer, your body loses approximately 280ml more water than it takes in. Over a day of drinking at a festival, this deficit adds up quickly.
Practical strategies for drinking alcohol while staying hydrated:
- Match every alcoholic drink with a glass of water. This is the single most effective rule. It slows your drinking, maintains your hydration, and significantly reduces the severity of hangovers.
- Drink water before your first alcoholic drink. Make sure you are well hydrated before you start drinking alcohol, not trying to rehydrate alongside it.
- Choose lower-ABV drinks. A 4% lager dehydrates you less than a 6% craft beer or a double spirit. Switching to lower-strength options later in the day helps.
- Drink water before bed. At the end of the evening, drink at least 500ml of water before you sleep. This does not fully prevent dehydration overnight, but it reduces it.
Special considerations
Children
Children dehydrate faster than adults and are less likely to recognise or communicate that they are thirsty. If you are at an event with children, actively offer them water regularly rather than waiting for them to ask. Avoid giving children caffeinated drinks, which have a mild diuretic effect.
Medications
Some medications, including certain blood pressure drugs, antihistamines, and diuretics, increase your risk of dehydration. If you take regular medication, check with your pharmacist or GP about whether you need to increase your fluid intake in hot weather.
Caffeine
Tea and coffee have a mild diuretic effect, but research suggests that in moderate amounts (three to four cups a day), the fluid they provide outweighs the fluid lost. You do not need to avoid caffeine at events, but do not count it as your primary hydration. Water remains the best option.
For more on looking after yourself at events, read our guide to feeling unwell at events and our outdoor event safety guide.
Staying hydrated is the simplest and most impactful thing you can do for your health and enjoyment at a summer event. Bring a bottle, fill it often, drink before you are thirsty, and match your alcoholic drinks with water. It is not glamorous advice, but it is the difference between having a great day and ending up in the medical tent.
