Altitude sickness usually occurs at heights of more than 2,430m (8,000ft) and can affect anyone, fit or unfit, experienced or not. It is usually avoidable if you take the correct steps. The aim of this article is to give you the best chance of enjoying a trip that includes higher altitudes, such as Peru’s Salkantay Trek to Machu Picchu and Inca Trail, Everest Base Camp treks and Annapurna Sanctuary, both in Nepal.

• Highest point on the Inca Trail is 5028m (16,495ft)
• Everest Base Camp, Nepal, is at an altitude of 5,364m (17,598ft).
• Annapurna Sanctuary is at 4130m (13,550feet)

Altitude sickness, also known as acute mountain sickness (AMS), occurs when the body is put under severe stress because of a decrease in oxygen levels at higher locations. Around 20% of people develop mild symptoms at altitudes between 1920m to 2960m (6,300ft and 9,700ft). AMS can cause symptoms such as:

• Insomnia
• Dizziness and light-headedness
• Racing heart or pulse
• Shortness of breath
• Fatigue and drowsiness
• Nausea or vomiting
• Loss of appetite
• Pins and needles.

In some cases altitude sickness can lead to more severe symptoms, such as Peripheral oedema (swelling of hands, feet, and face) and could prove to be the end of your on-high experience.

The best way to enjoy high altitudes

Proper acclimatisation is vital for preventing altitude sickness. This means ascending at a slower pace that allows your body to adapt to the change in altitude. The pace is not just slow, it takes many more days than you could ever envisage to climb safely to altitude. For example, on the Everest base camp in style trip you will not reach the camp until day 12 or your 19 day trip and every few days there are rest and "acclimatisation" days. Macs Adventure take the precaution of arranging trips that allow for time in which to properly acclimatise. Instead of being rushed to a place and then being expected to quickly climb to a height, the trips have built-in acclimatisation days. If it also worth noting that Macs Adventure will not advise you to fly to high altitude to save time or to have extra days at a high altitude location. With any trips that climb to higher places there is a wealth of advice given on how to reach these altitudes safely and with the least risk of sickness. Many trips also have local guides. It's worth noting, too, that trekking or hiking holiday that involves crossing ridges or low peaks but sleeping in the valleys is less likely to cause problems with altitude sickness, unlike a climb up an isolated peak such as Kilimanjaro.

Make sure you climb gradually

Do not ascend from a low altitude to sleeping at higher than 2,430m (8,000ft) above sea level in one day. Instead, spend a few days several hundred metres lower down before proceeding to a higher altitude. This allows your body to adjust to the lower oxygen levels. There is also a golden rule about sleeping at altitude. The key is to climb high, sleep low. Once you've made your way up past 3,000m (10,000ft), do not ascend more than 300m (1,000ft) per day to sleep. It’s possible to climb as high as you want, but make sure that you come back to a base camp that's no more than 300m higher than your previous night's sleeping elevation. Other tips include avoiding alcohol or doing heavy exercise for the first 48 hours after you arrive at an altitude above 2,400m. As an alternative, you might consider taking a day trip to a higher altitude. It’s less risky to take a day trip to a higher altitude and then return to a lower altitude to sleep. (This is also useful guideline if you're driving to a high altitude.)

Drink plenty of water

Hydration is also important. Some people will imagine that they have altitude sickness but it could easily be dehydration. At higher altitudes, more vapour is lost from the lungs so you need to drink more water. Also avoid caffeine and alcohol because these can increase the likelihood of dehydration. If it's humid at higher altitude and you find you are sweating, add a sports drink electrolyte tablet to water to maintain a good balance of electrolytes in your body.

Chat to your doctor

The natural way is best but there are medical aids for dealing with altitude sickness. If you know that you are prone to AMS it might be worth taking medication on holiday with you. Talk to your doctor about a prescription for acetazolamide. This works to make the blood more acidic, which improves oxygen saturation in the blood. Acetazolamide should be taken two days before you start to ascend and every day of the climb. You may also be advised to take it for a day after you have reached your highest altitude. But acetazolamide doesn’t work for everyone and side effects include increased urination, altered taste and a “pins-and-needles”. Ibuprofen has also been found to be helpful for high altitudes. A dose of 600 milligrams, three times a day, starting six hours before ascending was found, in a 2012 study, to work effectively. A more extreme product is called a “gamow bag”, which is a portable plastic pressure bag that is big enough to take a person and is inflated with a foot pump. This can reduce the effective altitude by as much as 1,500m.

6 high altitude tips

1. Go slow – and even slower than you thought possible. If you start to develop mild symptoms of altitude sickness, stay at your current altitude until your symptoms improve.

2. Rest and good hydration are the keys to recovery. If your symptoms get worse, immediately descend from your current altitude.

3. When ascending above 3000m, have a rest day every three days, after which you can climb higher but return to sleep at the same altitude as the night before. Stay well hydrated by drinking plenty of water.

4. Eat a high-calorie diet while at altitude.

5. Do not smoke, drink alcohol or use medication such as tranquillisers and sleeping pills because they can make the symptoms of altitude sickness worse.

6. The risk of sunburn and sunstroke is also increased at altitude so make sure you have high factor sun lotion, good quality sunglasses and stay out of the strongest hours of sunshine.