Altitude sickness is also known as acute mountain sickness and can happen to anyone, no matter what your fitness level, age or experience of climbing is. It affects your breathing and your ability to take in oxygen. This can be life-threatening. It happens when you travel to a higher altitude too quickly, typically greater than 2,500m above sea level, often when mountain climbing but also if travelling to cities that are high above sea level. (It isn’t possible to get altitude sickness in the UK because no mountain in the country is anywhere near 2,500m above sea level).

Motion sickness, or travel sickness, occurs when the movement of a car, train or boat you are travelling in causes a mismatch between the signals from the balance sensors in your ear and the sense of balance you get through eyesight. Think of being on a boat - it feels like it's rocking (the sensor in your ear tells your brain you're in motion) but when you look at the horizon, it's flat and still (your eyes tell your brain that you're stationary). This mismatch can cause some people to have symptoms of nausea, dizziness, headaches and feeling genuinely unwell. If you are on a mode of transport for more than a couple of days (such as on a cruise), the majority of people will find their body adapts and the symptoms improve. It is not known why some people suffer from motion sickness more than others. It is more common in women and people who suffer from migraines. It is also very common in children however the majority will grow out of it through their teenage years.