Acid indigestion's usually thought of as a festive health hazard, with all the rich grub, boozy parties and dashing around the season brings.

But heartburn, as it's also known, can strike in the summer too - and some of the potential triggers might come as a surprise.

Caused by stomach acid rising up the oesophagus (food pipe), resulting in a nasty burning sensation, around 8.2 million Brits suffer frequent bouts of heartburn, with symptoms striking twice a week or more. While it can be deeply unpleasant, it's not usually a sign of anything serious - although it's important to see your GP if it doesn't clear up, gets worse, or if you're also experiencing other worrying symptoms at the same time, such as vomiting or trouble swallowing.

The good news is, heartburn can be managed by avoiding certain things, and being prepared with appropriate medication if necessary.

Here are five summer triggers to be aware of...

1. Barbecues

As soon as the sun comes out (or even when it doesn't), we Brits love dusting down the barbecue. But according to a survey by Nexium Control, the non-prescription treatment for short-term relief of heartburn symptoms, almost a quarter (22%) of frequent heartburn sufferers say barbecues bring on symptoms - and it's not just the greasy meat that's to blame.

"Summer can increase the misery for frequent [heartburn] sufferers, due to changes in our eating habits. The average barbecue combination of fatty meats and salad can be the perfect trigger," says GP Dr Sarah Jarvis - not to mention the fact we often eat more, and more quickly (then wash it all down with wine or beer).

2. Sleeping in tents

Got a camping trip planned, or a summer festival? If you're prone to heartburn, don't forget to pack enough pillows - as sleeping completely flat on the ground could make acid reflux worse.

"Propping your head and upper chest up while you're sleeping can decrease the pain of acid reflux, as it stops the stomach acid from rising to your chest," says Dr Jarvis.

3. Crunches and sit-ups

Apparently, people generally workout more in summer. Be careful if you're embarking on an exercise plan with lots of sit-ups though, as these may contribute to heartburn. "Certain abdominal exercises, like stomach crunches, can push acid out of the stomach, causing heartburn," notes Dr Jarvis.

Of course, nobody's saying ditch the fitness regime - but if you do experience heartburn, it might be a good idea to change up your routine, and Dr Jarvis advises: "It's best to wait at least two hours after a meal before exercising."

4. Foreign food

Sampling the local cuisine is one of the great joys of travel. But for somebody prone to heartburn, changing your diet and introducing foods you're not familiar with can be a minefield. Nexium Control found more than a third (35%) of frequent heartburn sufferers say holidays are a common cause of flare-ups. Being prepared by packing appropriate medication, perhaps doing a little research about restaurants and avoiding alcohol can all help. Plus, feeling in control will help ease any anxiety around the symptoms - as that usually makes the problem worse.

5. Flying

Aeroplanes can be bothersome for digestion in general, and it's not uncommon to experience bouts of heartburn during flights. Apart from avoiding foods you know are problematic, you can't really trick your stomach into thinking it's not in the sky, so Dr Jarvis suggests: "If you regularly find yourself experiencing symptoms when flying, it's best to plan ahead and pack suitable medication to avoid symptoms. Ask your pharmacist about options which prevent symptoms, as opposed to treating them, which may benefit the jet-setting heartburn sufferer.