Dehydration: symptoms, effects and can it cause stomach pain?

Our bodies depend on water, and consuming too little of it can have serious consequences¹. Not drinking or consuming enough fluids, or losing too much too quickly, can result in dehydration. The effects then vary depending on how dehydrated you are.

Mild dehydration can sneak up on the best of us, though babies and older adults are most vulnerable to its impact².

There are a range of symptoms that can result from being dehydrated. We’ll cover common signs of dehydration below, as well as treatments and more in our comprehensive guide.

What is dehydration?

Dehydration is when your body loses too much fluid, or does not get enough¹. How it feels can vary, but when it happens you may suffer from a range of symptoms that could steadily worsen from mild, to moderate to severe if you don’t ‘re-hydrate’.

The difference in severity for adults is based on how much fluid is missing from your body. In children, it’s often measured by how much weight they’ve lost¹.

What are some of the causes of dehydration?

Dehydration usually occurs if someone doesn’t take in enough fluids, or they lose fluids faster than they can take in². Some specific circumstances can make you more vulnerable to dehydration than others.

These include:

• Sweating more than normal – If you exercise or are doing manual work, especially in hot weather, you may sweat more. Sweating is designed to keep you cool, but losing too much fluid in this manner can leave you dehydrated²

• Illnesses such as sickness bugs and diarrhoea – When we’re sick, vomiting and diarrhoea can prevent our body from retaining the fluids we need, resulting in dehydration²

• Diabetes – People with type 2 diabetes have high glucose levels in their blood. One of the side effects of this is excess sugar going into urine, and an increase in urination. This can ultimately lead to a reduction in fluids in the body³

• Drinking alcohol – Alcohol is a diuretic, which means it also makes you urinate more frequently. This happens because the hormone that controls water reabsorption is interfered with, and more urine fills up the bladder. Excessive urination, as we know, can contribute to dehydration⁴.

What are the main signs of dehydration in adults?

The symptoms of dehydration someone experiences will depend on the amount of fluid that’s missing from their body, as well as other potential factors.

• Feeling thirsty – A notable sign that you’re dehydrated is that you feel thirsty. Thirst is your body’s way of telling you to drink water, and shouldn’t be ignored¹

• Struggling to go to the toilet – Dehydration may leave you constipated, and the urine you do produce may be dark yellow in colour, with less volume than usual¹

• Dry skin – Skin contains approximately 30% water and relies on proper hydration for its health. A lack of water can result in dry skin⁵

• Dry mouth– One of the main causes for a dry mouth is dehydration⁹

• Headaches – When you’re dehydrated, pressure is put on the nerves around the skull, which can cause pain. While this might sound alarming, most dehydration headaches will pass after drinking water⁷

• Muscle cramps – Cramps or spasms can occur anywhere on the body and often follow excessive exercise or fatigue. Part of this, however, can be a result of dehydration and electrolyte imbalance⁸.

If you or someone you know is experiencing dehydration, you should seek medical advice and treatment immediately².

What is the impact of dehydration on kids?

Children and babies can be at risk of dehydration too, though the symptoms aren’t always the same that adults experience.

While older children might tell you if they’re thirsty, there are some key signs of dehydration to look out for in infants which are especially important to be aware of.

These may include:

• Fewer wet nappies than normal – Much like adults, babies will produce less urine if they’re dehydrated^9,11,

• Lack of tears when crying – Another sign that they don’t have enough fluids can be a lack of tears when they cry⁹, especially if this is not normal for them

• Sunken eyes – You might notice your baby’s eyes look like they’ve sunk into their skull. If combined with diarrhoea, this can be a sign of severe dehydration¹²

• A sunken soft spot at the top of a baby’s head – When babies are born, their skulls aren’t fully formed. When dehydrated, the gaps on the top of the skull can appear sunken.

Signs of dehydration in children and babies may indicate that they need urgent care. If you’re concerned, seek medical advice immediately².

Can dehydration cause stomach pain?

Dehydration and stomach pain are often associated with each other. This is mainly because water is important for digestion¹⁴, and stomach pain can therefore result indirectly from dehydration if your digestive system is impacted.

You might lose fluids if you get diarrhoea while ill, which can lead to dehydration-related cramps. Conversely, constipation can be a symptom of dehydration, and lead to further stomach and bowel discomfort¹⁴.

How can you treat dehydration effects?

There are a range of treatments that may help with dehydration and the symptoms you experience.

Drink fluids to replace the ones you’ve lost – One of the easiest solutions to dehydration is to drink water. It may sound simple, but whether you’ve lost fluids through sweating, or illness, you can often replace them with regular glasses of water². If you’re particularly forgetful or busy, you could set up an alarm to remind you to drink. You should be drinking enough that your urine is a pale clear colour²

Drink little and often when you’re unwell – If you’re feeling sick, you may not want to drink lots of liquids, even if you’re losing them. If this is the case, focus on lots of sips throughout the day. It should feel more manageable, without causing further feelings of nausea².

Consider oral rehydration solutions – If you’ve lost a lot of water, you may need to consume rehydration solutions to replace the salts and minerals that went with it. These can usually be purchased from a pharmacist, and will come as a powder you mix into water².

If you’re struggling with diarrhoea, with cramps, bloating and wind, IMODIUM® Dual Action Tablets can help provide relief.

For medically diagnosed Irritable Bowel Syndrome (IBS), IMODIUM® Instants can help with diarrhoea in adults aged over 18 years.

Always speak to a pharmacist or doctor if you have signs of dehydration.

When to seek medical attention

If dehydration persists or becomes severe, drinking fluids may not be enough and you should seek medical attention.

Dehydration symptoms – FAQs

What does dehydration feel like?

The feeling of dehydration will depend on its severity. If you have a mild case, you might only feel thirsty and maybe have an accompanying headache. If you’re moderately dehydrated, you might start to feel nauseous. If you’re severely dehydrated, you might have a rapid heartbeat, feel dizzy and disorientated, and you may even faint².

Can dehydration cause diarrhoea?

Dehydration won’t usually cause diarrhoea, but it can cause stomach pain and cramping. This is because water is essential for digestion¹⁴, and you’re more likely to experience constipation and pass less urine than usual when dehydrated. However, while dehydration doesn’t normally cause diarrhoea, diarrhoea can cause dehydration² – due to the loss of fluid your body experiences.

Is there a link between IBS and dehydration?

If you have IBS and experience diarrhoea from time to time, you might lose a lot of your body’s water as a result, which can lead to dehydration. If you’re experiencing diarrhoea because of IBS, be sure to drink fluids regularly to replace any that you’ve lost. Learn more about how you can manage the symptoms of IBS .