Water is essential for life but drinking too much or too little water can be harmful to health. If untreated, dehydration can get worse and can cause serious health problems. This blog post provides an evidence-based overview of the effects of dehydration on different organs and systems within the human body.
Mild dehydration can negatively affect cognitive function, reducing concentration, alertness, and short-term memory.
It can also result in significant changes to our mood, with increased feelings of fatigue, confusion, and anger. Studies have shown that rehydrating can quickly reverse some of these negative effects, resulting in increased alertness.
Older adults are particularly susceptible to the cognitive effects of dehydration – it’s a major risk factor for delirium (which is common in older people with dementia). For further advice on helping older adults meet their hydration needs, click
Dehydration has also been linked with headaches, with some evidence indicating that insufficient water intake can trigger and prolong migraines. The good news is that rehydration may help to relieve dehydration-induced headaches in as little as 30 minutes.
Our kidneys are responsible for regulating fluid balance and blood pressure. They also filter out and remove waste products from our bodies in our urine.
The kidneys require a steady supply of water to ensuring that our natural, in-built filtration system is working optimally.
During dehydration, the kidneys adapt by producing concentrated urine (i.e. darker in colour). However, this puts a greater strain on the organ, so remaining well hydrated helps to protect the kidneys.
Dehydration may also increase our risk of developing urinary tract infections (UTIs). In people at high risk from UTIs, a rigorous and structured approach to hydration has been shown to result in a large reduction of cases.
Water is important for maintaining healthy skin – in fact, water contributes 30% of our skin mass.
People who have a consistently low water intake may be able to improve their skin thickness, density, and hydration by increasing their water intake and remaining well-hydrated.
However, there is no evidence available to suggest that dehydration is directly related to the onset of skin conditions such as hives and eczema.
Our fluid intake influences our blood volume. Therefore, the loss of body water, for example through sweat during exercise, can result in a decrease in blood volume. This can result in increased heart rate, reduced blood pressure, and occasionally fainting.
Always protect your health by staying well hydrated. Discover the daily recommended water intake.