Remember when your grandma used to say that she knew when a storm was coming because she could "feel it in her bones"? It turns out that she may not have been as crazy as you thought. Changes in barometric pressure that accompany storms and shifts in weather patterns do affect our bodies, and many people are more sensitive to those effects than others.

Although it's been indicated as a possible cause for everything from changes in blood pressure to an increase in joint pain, it can be difficult to pinpoint barometric pressure changes as the definitive cause for these issues when so many other atmospheric changes — like temperature, precipitation and wind speed and direction — often accompany shifts in weather.

Still, enough people experience symptoms when the barometric pressure changes, so it's worth noting. Here's a look at some of the ways that changes in atmospheric pressure might affect your body:

Blood pressure: Just as its name implies, our blood moves through our bodies using a pressure system created by the heart. So it makes sense that this pressure would be affected by the pressure in the air around us. According to biometeorologist Jennifer Vanos, Ph.D., when the barometric pressure drops, so does your blood pressure. For some, this might mean a feeling of dizziness or even blurred vision.

Headaches: In an interview with the New York Times, Dr. Matthew Fink, neurologist in chief at New York-Presbyterian Hospital/Weill Cornell Medical Center, explained that low barometric pressure can cause headaches or migraines by creating a pressure difference between the atmosphere and the air-filled sinuses. The problem is exacerbated when the sinuses are congested or blocked for any reason.

In a study published in the journal Internal Medicine, researchers asked migraine patients to keep a headache diary for one year. After comparing these diaries with the barometric pressure changes noted at the nearby weather station, they found a direct correlation between lower atmospheric pressure and the onset and duration of migraines. Their report concluded that "barometric pressure change can be one of the exacerbating factors of migraine headaches."

Joint pain: Researchers at Tufts-New England Medical Center in Boston surveyed 200 patients with knee osteoarthritis and found a link between changes in barometric pressure and ambient temperature and changes in knee pain severity. It's not clear why a falling barometer would exacerbate joint pain and arthritis, but studies such as this one confirm that they do. It could be that barometric pressure affects the viscosity of the fluid that lines joint sacs, or it could be that it triggers the pain responses in the nerve endings of the joint. Either way, it's what your grandma has been saying for years: Some people feel pain in their joints when a storm is approaching.

Blood sugar: "Diabetics will have more trouble controlling their blood sugar during cold fronts," said Vanos. And what accompanies cold fronts? You guessed it: changes in barometric pressure. According to Vanos, blood viscosity, or thickness, increases during cold fronts, making it more difficult to keep blood sugar at stable levels.

Diabetics who use an insulin pump to control sugar levels should also be careful. The American Diabetes Association conducted a study on the relationship between the effectiveness of insulin pumps with variations in air pressure and found that decreases in air pressure "may cause trapped air in the pump to form small bubbles that affect the delivery of insulin and the amount actually being delivered." While this study focused on the changes in atmospheric pressure that occur with air travel, it's still worth noting that sudden drops in barometric pressure could affect the effectiveness of your insulin pump.