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What do you think of when talking about managing high blood pressure? The words ‘hypertension’, ‘diet’, ‘stress’, and ‘exercise’ might spring to mind, but there is an overlooked contributor that might surprise you: hydration. Dehydration might not only contribute to high blood pressure but could also be exacerbating other underlying health problems.
We’ve taken a look at the connection between hydration and blood pressure, and how dehydration affects your heart and blood vessels, and why staying properly hydrated could be one of the simplest and most effective lifestyle changes for your heart health.
Blood pressure is the force of your blood pushing against the walls of your arteries, and it’s measured using two numbers:
Systolic pressure – The pressure when your heart beats.
Diastolic pressure – The pressure when your heart rests in between beats.
A healthy blood pressure reading is typically around 120/80mmHg. Having high blood pressure means that your heart is working harder than it should be, which can increase the risk of heart attack, stroke, kidney disease and other health complications.
Water plays an important role in every bodily function, from regulating blood volume to supporting heart health. Here’s how dehydration can directly impact your blood pressure:
Reduced blood volume – When you become dehydrated your total blood volume decreases. Blood can become thicker and more concentrated causing your heart to pump harder so that the same amount of oxygen and nutrients can be carried through your system. This causes extra strain which can lead your blood pressure rising.
Increased vasopressin secretion - Dehydration releases a hormone called vasopressin. This hormone signals your kidneys to retain water but also causes blood vessels to constrict. This constriction raises blood pressure, sometimes considerably.
Electrolyte imbalance – Water loss can also lead to an imbalance of sodium, potassium and other electrolytes. These are what help regulate muscle function, including the heart.
Kidney stress – Your kidneys help to control blood pressure by regulating fluid and sodium levels. Dehydration limits kidney function and can make them retain more sodium, which contributes to hypertension.
If you have a busy lifestyle, it can be easy to ignore or overlook mild or moderate signs of dehydration. Common signs include:
If you suffer with high blood pressure, even mild dehydration could be enough to push it up into a dangerous level.
There are some demographics that are more vulnerable to dehydration and its effects on blood pressure. These are, but not confined to:
Older people – Seniors may find that with age their sense of thirst is not the same as when they were younger. Kidney function can decline when not hydrated.
People on diuretics – Blood pressure medications can increase urination, which can dehydrate the body if fluid intake isn’t adjusted for this.
Athletes and active people – High fluid loss through sweating can lead to fast dehydration.
Those with chronic illnesses – Conditions like diabetes or kidney disease can complicate fluid regulation, so extra care is needed.
Yes! Acute dehydration can also cause low blood pressure (hypotension), especially where there has been extreme fluid loss (e.g. due to sickness and diarrhoea, or excessive sweating). That said, mild to moderate dehydration is more commonly associated with high blood pressure as outlined earlier.
These contrasting conditions show just how important proper hydration is in maintaining cardiovascular balance.
There is no exact measurement, as everybody is different, and so are their hydration needs. But common guidelines suggest that on average 6-8 glasses (1.5-2 litres) of fluids per day is about right for most adults. As mentioned, this amount can vary depending on on age, body size, activity level, and climate.
So, how can you improve your hydration habits? Ideas below!
Start and end your day with water – Drink a glass of water first thing in the morning and last thing in the evening to rehydrate.
Carry a refillable water bottle – Having water on hand makes it easier to sip throughout the day.
Monitor your caffeine and alcohol intake – Both of these have dehydrating effects, so balance them out with extra water (fun fact: alternating between alcohol and water is called zebra striping – who knew!?).
Eat water rich foods – Fruits like watermelon, oranges, and cucumber can boost your fluid intake naturally.
Install a water cooler – Staying hydrated at work can be tricky, particularly if you’re busy. A water cooler is a visual reminder to keep your fluid levels topped up.
Hydration is only part of the picture, but it does support every other intervention for high blood pressure. Here’s why:
Exercise – You can’t perform at your best, or recover well, if you’re dehydrated.
Medication efficacy – Many medications for hypertension are processed by the kidneys or liver which function much better when well hydrated.
Stress Management – Dehydration has been linked to higher cortisol levels, making it harder to manage stress and anxiety.
Learning to combine hydration with other healthy habits can improve your results and lead to better blood pressure control over time.
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At CoolerAid, we’re passionate about hydration because we know it’s not just about quenching thirst - it’s about looking after our long-term health and well-being. Investing in good hydration habits could be one of the easiest steps toward lowering your blood pressure naturally.
So, the next time you reach for a cup of coffee or a fizzy or alcoholic drink, pause for a moment and consider reaching for water instead. Your heart will thank you for it!
