Dry mouth in hot weather: how to protect your teeth on summer days

Summer brings long days outdoors, more sweating and more cold drinks, and a mouth that feels dry and sticky by mid-afternoon. It is easy to dismiss. It is also worth a little attention, because saliva helps protect your teeth, and the NHS says you are more likely to get tooth decay if you have a dry mouth.

This guide covers what the NHS says causes a dry mouth, what to do about it on hot days and when to ask a professional. It is about everyday dryness, not a diagnosis.

What causes a dry mouth

The NHS lists the main causes of a dry mouth as dehydration, medicines, breathing through your mouth at night, anxiety, cancer treatment and oral thrush. Dehydration, it says, can come from not drinking enough, sweating a lot or being ill. Sometimes a dry mouth that does not go away is caused by a condition such as diabetes or Sjögren’s syndrome.

Hot weather mostly affects the first item. The NHS separately lists dehydration as one of the main risks of a heatwave, and says people who spend a lot of time outside, particularly if they are physically active, are more vulnerable. So on a hot day, a dry mouth can be a small warning to drink more and slow down.

A hot-day routine for your teeth

None of this is complicated, and all of it follows the NHS advice.

1. Sip cold water through the day rather than drinking a lot at once, and keep some by your bed at night.
2. Choose cold, unsweetened drinks. The NHS advises avoiding lots of alcohol, caffeine and fizzy drinks, and acidic, spicy, salty or sugary foods, when your mouth is dry.
3. Chew sugar-free gum or suck sugar-free sweets if your mouth feels dry between drinks. The NHS also lists ice cubes and ice lollies.
4. Brush twice a day for about 2 minutes with fluoride toothpaste, including last thing at night, and clean between your teeth every day with floss or interdental brushes. Our guide to bleeding gums when flossing covers what to do if your gums protest.
5. Spit, don’t rinse. After brushing, spit out the excess toothpaste and do not rinse straight away, because rinsing washes away the concentrated fluoride in the paste that is left.
6. Use an alcohol-free mouthwash at a different time from brushing, such as after lunch. The NHS says not to use mouthwash straight after brushing, and not to eat or drink for 30 minutes after a fluoride mouthwash.

If you use a water flosser, the same daily cleaning between teeth applies on a hot day. Our water flosser versus string floss guide helps you choose.

Lower the heat load

A dry mouth is partly a sign that your body is working hard to cool itself, so reducing heat helps. The NHS advises that in hot weather you keep out of the heat if you can and, if you must go out, stay in the shade, especially between 11am and 3pm, wear sunscreen, a hat and light clothes, and avoid activity that makes you hotter.

A compact umbrella is one portable way to make shade on a bus-stop wait or a walk without trees. Calm Eden, which has the same owner as FlosserGuide, explains the limits in its guide on whether umbrellas block heat. Shade does not replace water, sunscreen, a hat or staying indoors in the hottest hours, and the NHS says to watch for signs of heat exhaustion and heatstroke.

Things that make it worse

• Lots of alcohol, caffeine or fizzy drinks
• Smoking, which the NHS says to avoid
• Acidic, spicy, salty or sugary foods when your mouth is already dry
• Sleeping with dentures in, if you wear them
• Stopping a prescribed medicine without advice. The NHS says not to do this even if you think the medicine might be causing the dryness. Ask a pharmacist or GP first.

A pharmacist can help

If home measures are not enough, the NHS says a pharmacist can suggest gels, sprays or tablets and lozenges to keep your mouth moist. Not all products suit everyone, so ask which is right for you. The NHS also says not to use acidic artificial saliva products if you have your own teeth.

When to see a GP or dentist

The NHS says to see a GP if you have a dry mouth and any of these apply: it makes talking or eating difficult, it is still dry after a few weeks of home or pharmacy treatment, you are struggling to eat regularly, your sense of taste is changing, your mouth is painful, red, swollen or bleeding, you have sore white patches, you think a medicine is the cause, or you have other symptoms such as needing to pee a lot or dry eyes. A dentist can check your teeth and advise on fluoride if dryness is an ongoing problem.

A note on the umbrella mention

The only product we name is Calm Eden’s Haven Umbrella, which is listed with an SPF 50+ canopy that blocks 99.99% of UV, one-press opening and closing, a folded length of 40 cm (15.75 in) and a weight of about 390 g. These figures come from the listing. FlosserGuide has not tested the umbrella, and the shared ownership means this is a disclosure, not a recommendation.

Sources

• NHS: Dry mouth.
• NHS: How to keep your teeth clean.
• NHS: Heatwave: how to cope in hot weather.

This guide summarizes published NHS guidance. Nothing here is a diagnosis or personal medical or dental advice; ask your own dentist, pharmacist or doctor about your case.