In 2017, Nepal was named as one of the top travel destinations by The Lonely Planet and saw approximately 940,200 visitors in the same year according to Nepal’s tourism board. It is clearly a popular destination, with much to offer all year round – one of the main reasons being the mighty Himalayas that stretch some 500 miles (800 km) across the country from the Kali River in the west to the Tista River in the east. Nepal is a country of great geographical diversity with the altitude ranging between 4,877 meters and 8,884 meters – Mount Everest being the highest peak.

With these extreme altitudes, acclimatization is one of the main things to plan for. At sea level, oxygen makes up about 21% of the air we breathe, dwindling down to about 13% at 3,600 meters. Oxygen is scarce in most parts of the Himalayas and even Everest’s renowned base camp sits at a breathless 5,364 meters. There is plenty of information out there on altitude sickness and the effect it can have on you, but what happens to our bodies when we’re sleeping and trying to rest at these heights?

The physics of sleeping at altitude

When you get to altitudes of 2,500 meters and over, your body will inevitably respond in some way to the thinner air. How you respond will depend on a number of factors including how quickly you got to that altitude, the final altitude reached and at what altitude you choose to sleep at.

When we sleep at very high altitudes, carbon dioxide levels in the blood tend to drop. In some people, they can drop so low that they can switch off the bodies natural drive to breathe. It’s only when your body realizes the significant drop in oxygen levels that the breathing reflex kicks in again, resulting in rapid or deep breathing. This cycle can continue for a whole night of sleep and is called high altitude periodic breathing. It is most common at altitudes above 1,828 meters (6000 feet) and can cause you to wake frequently at night and make you feel like you can’t breathe. These results in less sleep time over time with increased levels of fatigue that can add to the effects you’re already feeling from the altitude. All these additional factors can affect your mental impairment and decision making.

What should you do?

If you’re heading for the Himalayas, you should already have some sort of risk management or safety plan. Make sleep a part of that plan. There are a number of places along the routes in the Nepal trekking where you can get a comfortable night’s sleep. These include lodges, home stays, campsites and hotels, but if you’re choosing to camp, a few extra comforts might be needed to ensure you get the rest you need.

Start by climbing slowly. Acclimatizing at a steady pace allows your lungs to get more air through slow, deep breathing which allows the red blood cells to transport more oxygen to the rest of the body.

‘Climb high and sleep low, says Carol DerSarkissian an Emergency Physician talking about altitude sickness on WebMD. For example, if you climb up to and remain at an altitude of 2,700 meters, try and spend that night at 2,400 meters. If you’re heading for a goal height, then keep doing that as you go each day, ‘stair casing’ your climb and sleep.

It might just be that you need to plan for a few bad night’s sleep while you acclimatize. You should ensure this is part of your plan so you can stay focused, alert and safe throughout your trip.

Tags: altitude sickness