### What barometric pressure means for hikers

• Feb 3, 2015

When you're preparing to climb at high altitudes, you'll want to have your watch barometer handy for the trip. However, if you've never hiked at high altitudes before, you may not know much about what a barometer can do and how pressure affects your climb. It's important that every hiker know at least the basics before ascending or else risk serious health issues on the way up or down.

What is a barometer?
A barometer is a tool that measures the air pressure, similar to a thermometer with temperature. Some barometers use mercury, like thermometers, that react to the air pressure above them. However, watch barometers are able to give you a simple read out on the wrist.

What is air pressure?
Knowing what a barometer is or how to use it is pointless if you don't understand air pressure. Air pressure, or barometric pressure, is the measurement of how much air is above any one area at a given time. The more air, the more pressure that it exerts down on the space below. Therefore, the higher you go up from sea level, the less the air pressure.

Air pressure can also change with temperature and weather, and it is a main factor used by meteorologists in determining incoming weather patterns, USA Today explained.

The air pressure at sea level is 14.7 pounds per square inch, or 1,013 hectopascals. The phrase "a rising barometer" means that air pressure is increasing, while a "falling barometer" indicates a drop in pressure.

As the air pressure changes, the amount of oxygen present does too. While there isn't a lower percentage of oxygen, the air isn't as dense because there's less air above it forcing it downward and compacting the gas molecules. This lack of oxygen is the main reason for health concerns about hiking at a higher altitude.

Mountain climbing advice website Hiking Dude reminded outdoorsmen that every foot they climb they're losing air pressure and temperature. {This paragraph and the next seem like it would fit better in the above section. It explains the concept}

"The higher you climb, the less air there is above you ... so the lower the air pressure and the less dense the gas," the website explained. "Every 1000 feet you climb, you lose about 3 percent of the available oxygen because there is less gas packed into your column of air. At 12,000 feet, every breath you take brings in only two-thirds the amount of oxygen that you would suck in at sea level."

Concerns about hiking in thin air
Bringing less oxygen into your lungs and hiking at these air pressures can lead to altitude sickness or worse conditions, such as a High Altitude Pulmonary Edema, which causes fluid to go into your lungs. These illnesses are characterized by nausea, headaches, changes in movement abilities, fatigue, confusion and disorientation.

To avoid these conditions, Hiking Dude suggested you adjust your hike to make up for there being less oxygen. The first step is to acclimatize, or let your body adjust to hiking at heights that it's not used to. This may mean adjusting your pace or waiting until your body is comfortable with the pressure. Hydration and eating are important as well - make sure you consume plenty of carbohydrates.

You'll also want to slow down all of your hiking, walk slower, stop more and generally breathe better. The other concern at this altitude is the sun. Just as there's less air pressure, there's more solar power. Prepare with sunglasses, long clothing and sunscreen, the website recommended.

Knowing more about altitude and air pressure can allow you to use your watch barometer as a tool to help you prepare for health concerns as you approach the summit.

The PRG270 watch, incorporates Casio's new triple sensor engine that includes a compass, altimeter and barometer. The barometer features a Barometric Pressure Tendency Alarm that alerts the wearer of sudden changes in air pressure. Having this watch handy will allow you to overcome mountains, safely and efficiently.