Blocked Ears

As the atmospheric pressure falls when your aircraft takes
off, the outside pressure changes faster than inside the ear or sinus. That's why it's natural for the ears to pop.

If you're travelling with a baby or small children, the hole leading into their ear is so tiny, pressure can take extra time to equalise. Pain and dizziness can be the result. This is also the case if you have allergies.

What to do:

• Chew gum, yawn and swallow often. Try pinching the nostrils and exhaling without opening your mouth. If you have a cold or allergy, take a decongestant before jetting off. This thins
  out the lining of the throat and allows air to flow and pressure to equalise. For babies, try giving a dummy or bottle on take-off and landing.

Respiratory problems

If, because of asthma, bronchitis or heart failure, you have difficulty breathing normally on the ground, the oxygen flow in a plane might not be enough.

What to do:

• Have your doctor check your oxygen saturation levels. If they're more than 92 per cent, then you're safe to fly. If not, you may have to use extra oxygen during the flight.

Nervous nellies

Most sufferers won't admit it, but millions of people around the world are left gripping the seat in white-knuckled terror when they board a plane.

What to do:

• Remember aeroplanes are designed to take any turbulence bad weather can dish out, so don't be scared of big bumps.
• Medication can help, but if you're travelling long distance, being sedated for hours on end is not ideal as this increases the risk of DVT (deep vein thrombosis). That's why anxiety medication rather than sleeping tablets might be better. Speak to
  your doctor or try a Fear Of Flying course, such as
  www.fearlessflyers.com.au

Aeroplane lurgies

Modern aircraft have developed very efficient anti-bacterial and viral filters for the air, similar to those in operating theatres.

But while this will protect you from the rest of the aircraft, you're not necessarily protected from someone sitting close to you. In other words, if someone in your row is unwell, you can definitely catch what they're suffering from. Indeed, one single patient with SARS (severe acute respiratory syndrome) infected 22 others on a flight from Hong Kong to Beijing.

What to do:

• Sleep well before a flight to strengthen immunity. Maximise airflow in the cabin by keeping your overhead vent open.

Economy Class Syndrome

Despite its name, you don't have to be squashed in economy to suffer from this. When you sit longer than four hours and breathe in dry air, which sucks moisture from the body, blood becomes sluggish and more likely to clot.

What to do:

• Don't drink alcohol, tea or coffee. These can dehydrate and make the risk of DVT much greater, as do sleeping tablets, which make you immobile.
• Take half an aspirin every day for a week before travelling a long distance. Check with your doctor first, as some asthmatics or people with tummy troubles should not take it. Those with a family history of blood clots, or those who have recently had surgery or some types of cancer, are also more prone to DVT.
• Keep mobile. Exercise when seated by making your calf muscles contract and relax and take a walk every hour or so.
• Compression stockings from the pharmacy are a good idea, but make sure they apply pressure of 20 to 30 mm/HG otherwise they're ineffective.
• Drink plenty of water.

Top tip

Airport security can interfere with pacemakers or other implanted devices such as defibrillators. If you've got one, ask the screener to ensure the wand is only held over you for a few seconds and to wait 30 seconds before using the device again.

For more health advice with Dr John, check out the latest issue of New Idea - on sale now!