How do I manage fluid restriction in hot weather? 

What is fluid restriction for heart failure?

If you live with heart failure and have symptoms, your healthcare team may have advised you to limit how much fluid you drink each day. This is called 'fluid restriction'.

It’s done to prevent extra fluid building up in your body, which if left unmanaged means your heart muscle may have to work harder to pump blood around your body, and can lead to symptoms such as:

• swollen ankles and feet
• breathlessness
• sudden weight gain
• tiredness/fatigue.

If you are advised to do fluid restriction because you have symptoms, your doctor or nurse will tell you how much you can drink each day.

But, as a guide, the UK’s National Institute for Health and Care Excellence (NICE) recommends restricting fluids to about 6 to 8 cups (1.5 to 2 litres) a day.

Your healthcare team will also let you know how long you need to limit your fluid intake for. In most cases it is only advised for a few weeks, and you will be closely monitored by your healthcare team.

How do I manage fluid restriction in hot weather?

Feeling thirsty is often the hardest part of being on fluid restriction. And when the weather’s warm, you'll likely feel even thirstier because your body's losing more fluids than usual through sweating.

If you lose too much fluid through sweating, and do not replace it by drinking, you could be in danger of dehydration, which can worsen your heart failure symptoms.

This is why, when the weather warms up, you should check with your healthcare team if you should continue with fluid restriction or not.

As a guide, NICE states that when there’s high heat and humidity you should increase your fluid intake to prevent dehydration if you’re on fluid restriction.

It’s important to know that fluid restriction is not about making you feel thirsty – which is your body’s way of saying it needs more fluids.

It’s about managing the fluid in your body, so it can work as well as possible, even in hot weather.

If you are not on fluid restriction and have stable heart failure, the latest research in Nature Medicine suggests you can safely drink fluids whenever you’re thirsty, especially when the weather is warm.

Tips for managing thirst

If you are on fluid restriction and suffer with thirst, the good news is there are safe ways to stay comfortable without putting extra strain on your heart.

Simple in the moment tricks

• Take small sips of fluid rather than large drinks.
• Use a smaller cup so your drink lasts longer.
• Suck on ice chips or frozen fruit pieces.
• Chew sugar-free gum to freshen your mouth.
• Rinse your mouth with cool water and then spit it out.
• Brush your teeth to reduce a dry mouth.
• Have cold drinks rather than warm ones as they can feel more refreshing.

Plan your daily fluids

Spread your drinks across the day rather than drinking a lot at once. You might find it helpful to:

• Measure your daily allowance in the morning.
• Keep a track of what you are drinking using a bottle or jug.
• Save a small amount of you daily fluid count for the evening.

Remember that foods like soup, jelly, ice cream, and juicy fruit also count toward your total.

Stay cool when it’s hot

Keeping your body cool in hot weather can help alleviate thirst and prevent sweating. So try to:

• Stay in the shade or indoors during the hottest part of the day.
• Wear loose, light clothing.
• Use a fan or cool cloth on your neck.
• Take a lukewarm shower.
• Keep rooms well ventilated.

When do I need to seek medical care?

Hot weather can affect your fluid balance in different ways. You should watch out for the below signs as they may mean your fluid restriction needs adjusting, or your heart failure medicines need reviewing.

Contact your healthcare team if you notice:

• sudden weight gain
• increased swelling
• more breathlessness
• extreme thirst
• feeling dizzy or unwell.

Never change your fluid limit on your own. If a heatwave is expected, or you are struggling with thirst, speak to your nurse or doctor. They can guide you safely.

Living with heart failure in hot weather can feel challenging, but small changes can make a big difference.

By managing thirst in the moment, following your fluid plan and staying cool, you can help protect your heart while still enjoying warmer days.

If you’re unsure about anything, your healthcare team is always there to support you.

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