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Posted at 11:00 AM ET, 11/19/2009

Feeling under pressure by air pressure?

Wx in the City

* Rain at times today: Full Forecast *

There is no doubt that weather affects our health and well-being -- think hypothermia, sunburn and that good old "nice day" feeling from a clear, warm spring day. There is an entire field called biometeorology that is dedicated to studying the interactions between the atmosphere and living things. But, do minor changes in air pressure, which we experience on a weekly basis in the form of high and low pressure systems, affect our health?

It's plausible.

Keep reading for more on the effects of air pressure on how you feel. But first, take this poll...

Thousands of miles of air are pressing down upon each of us at this very moment. However, we don't feel this weight because air is also all around us and in our bodies pressing back out, keeping us in equilibrium with the air above. We might take notice of changes to this balance when our ears pop while riding through an underground tunnel on a Metro train, taking off and landing in an airplane or diving underwater.

Air pressure (also known as atmospheric pressure or barometric pressure) is the force exerted by the weight of air, and it differs depending on where you are in the atmosphere. Air pressure is lower, thus fewer air molecules are present, at higher altitudes; you may have felt the effect of fewer oxygen molecules when hiking to the top of a mountain.

Closer to the Earth's surface, the movement of air across a pressure gradient creates wind and fuels the movement of weather systems around the globe. Air moves from areas of high air pressure, where there are more air molecules, to areas of lower air pressure, where there fewer air molecules. (I can't blame it: I feel the same way every time I'm in a crowded room.)

We see areas of high and low pressure on weather maps. In areas of high pressure (represented by 'H'), air is slowly sinking, meaning there are more air molecules exerting a pressure on Earth's surface, or on our heads for that matter. High pressure systems bring sunny, clear skies. On the flip side, in areas of low pressure (represented by 'L'), air is slowly rising and cooling, reducing the number of air molecules exerted on Earth's surface. Low pressure systems bring overcast skies and sometimes storms and precipitation (more information about high and low air pressure).

With all of this air sinking and rising around us, we should be thankful that our bodies are as adapted as they are, rather than turning to mush when high air pressure approaches or blowing up like a balloon (giving new meaning to the term 'air head') when low air pressure arrives (video: how air pressure affects objects).

Very little has been proven as to the effects of air pressure changes on human health, other than low air pressure causing an expansion of some large blood vessels and an increase in the symptoms of those who suffer from joint pain.

Is today's damp weather (and relatively low pressure) affecting you? Do you generally feel differently in high versus low pressure weather?

By  |  11:00 AM ET, 11/19/2009

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