What is altitude and elevation?
The simple definition of altitude is the height of an object in motion in relation to sea level or ground level. For example, an airplane reaches cruising altitude at 10,000 feet.
The simple definition of elevation specifically refers to the height of a fixed point on the Earth’s surface above sea level, like the peak of a mountain or top of a building.
A neat example of elevation is that Mount St. Helens is only 50 miles from the Pacific ocean and the elevation difference is 8,363 feet! An example of altitude is that most commercial airplanes fly at altitudes between 30,000 feet and 42,000 feet above sea level.
What is Barometric Pressure?
Barometric pressure is the weight of the air pressing down on the Earth’s surface, and it changes constantly. You may experience this in your day to day life and not even know it.
Increasing Pressure: The sensation of your ears popping while driving down a hill is caused by a rapid change in barometric or atmospheric pressure. The same sensation can be felt going down an elevator in a tall building or dropping in altitude in an airplane . Barometric pressure is higher at lower altitudes because there is more air molecules above you and the weight of these air molecules presses down on the surface creating greater pressure.
Decreasing pressure: As you drive up a hill, the elevation increases. At higher altitudes the air becomes thinner, and the barometric pressure decreases. Barometric pressure decreases at higher altitudes because there is less air above you and therefore less weight of air pressing down on you. A great example is when hiking at higher altitudes you will notice the air is much harder to breathe and may require an O2 (oxygen) bottle. While the percentage of oxygen remains around 21%, the lower atmospheric pressure reduces the partial pressure of oxygen, making it harder for your body to take in oxygen with each breath. This is known as hypoxia and can lead to symptoms of fatigue, shortness of breath, headache, confusion, rapid heart rate and chest pain. The partial pressure of oxygen is the pressure exerted by oxygen within a mixture of gases driving its movement from an area of higher pressure (like the lungs) to lower pressure areas (like the blood and tissues) until it reaches balance.
How are They Related?
Altitude, elevation and barometric pressure have an inverse relationship. This means no mater what, the higher you go the lower the air presser and the lower you go the higher the pressure. Always be prepared when hiking at high elevations knowing the air pressure is low. Acclimating and letting your body adjust to high elevation is important. This can take up to 3-5 days if you are from locations of lower elevation, like a trip from Florida to Colorado. Usually taking your time on an ascent will help you avoid elevation sickness as well as bringing a small bottle of supplemental oxygen in very high elevation climbs. Also note bringing an inhaler if you suffer from asthma, for it will worsen at higher elevation and altitudes.
