Have you ever felt dizzy or lightheaded after standing up? You might just chalk it up to standing up too fast and move on with your day.

Still, it's certainly off-putting — even if it only happens every now and then.

This odd phenomenon is called orthostatic hypotension, or postural hypotension. Don't worry, its explanation is less complicated than its names might imply.

According to the American Academy of Family Physicians, orthostatic hypotension is a form of low blood pressure that occurs when standing, since the change in gravity causes blood to pool in your legs for a short period of time.

For most, this shift goes unnoticed. For some, though, this quick drop in blood pressure feels...weird.

The full range of orthostatic hypotension symptoms include:

• Dizziness and lightheadedness when standing up
• Weakness
• Blurry vision
• Fainting
  
  

Most of the time, feeling dizzy when you stand up is just a temporary nuisance, caused by something that's fairly easy to correct. However, it can lead to a dangerous fall if severe and can also be a sign of an underlying health condition so it's important to tell your doctor if it's happening frequently.

7 causes of orthostatic hypotension, as well as ways to counteract it

There are many reasons for experiencing acute or chronic orthostatic hypertension. Common ones include:

1. Dehydration

When you're dehydrated, your blood volume is reduced. This leads to a drop in your blood pressure, which can make dizziness or lightheadedness more likely upon standing.

The most common reasons for dehydration include:

• Not drinking enough water every day
• Sweating a lot
• Being ill, particularly if you have severe diarrhea or are vomiting
  
  

You can prevent dehydration by knowing how much water you should drink every day and taking steps to make sure you get that much.

If you're losing excess fluids through your sweat or due to an illness, be sure to sip on something that replenishes lost water and electrolytes, like a sports drink. This is helpful because electrolyte imbalance can affect how well your body retains the fluids you're drinking.

2. Sitting or lying down for a long period of time

Your body position can affect your blood pressure, with slight changes occurring as you transition from sitting or lying down to standing. The reason for this is essentially the same as the reason orthostatic hypotension even happens in the first place. Moving into an upright position causes blood to temporarily pool in your lower body, leading to a slight drop in your blood pressure.

You can account for this by standing up slowly and giving your body time to adjust. This may be especially important when you get out of bed in the morning, since this is when your blood pressure is already at its lowest.

Orthostatic hypotension can also result from bed rest, in which a person has had to stay sitting and lying down in bed for a long period of time due to injury or illness.

3. Overheating

Being in the heat can lead to excessive sweating and, if you're not replenishing that lost sweat, dehydration. Dehydration impairs your body's ability to regulate its temperature and reduces your blood volume, which can lower your blood pressure. This makes dizziness or lightheadedness when standing more likely.

When you're out in the heat, be sure to drink plenty of water and seek shade if you feel like you're overheating.

If you're sweating a lot, again, drink a beverage that contains not just water but also the electrolytes you're losing in your sweat — important because electrolyte imbalance can impair retention of the fluids you drink. (Related: Sports Drinks Vs. Water: When Is One a Better Option Over the Other?)

4. Alcohol

Maybe you've heard that, over time, excessive alcohol intake can lead to high blood pressure.

But did you know that, in the short term, drinking alcohol can also lead to low blood pressure, which increases your risk of orthostatic hypotension? This is because it narrows your blood vessels and slows blood flow.

So it's no surprise that alcohol can make it more likely for you to feel weird when standing up — especially when combined with the dizzying effects that alcohol can already cause due to its effect on your inner ear system, which coordinates movement and balance.

5. Pregnancy

In the first 24 weeks of pregnancy, you might experience lower blood pressure as your body makes the circulation changes needed to support both you and your baby. This can cause the symptoms of orthostatic hypotension to be felt more readily.

Again, you can compensate for this by standing up slowly and giving your body time to adjust. This may be especially important when you get out of bed in the morning, since this is when a person's blood pressure is already at its lowest.

6. Medications you're taking

If you frequently feel dizzy or lightheaded after standing up, one of the first questions a doctor might ask is: What medications are you taking?

That's because certain medications can cause orthostatic hypotension, including those used to treat:

• High blood pressure
• Chest pain
• Depression
• Erectile dysfunction
  
  

In addition, low blood pressure can result from taking high blood pressure medication in combination with certain over-the-counter medications.

It's important to review your medications with your doctor if you're experiencing orthostatic hypotension frequently.

7. Certain health conditions

Another reason to consult your doctor if you frequently feel dizzy or lightheaded after standing up is that it could be a sign of something more serious.

Health conditions that can cause orthostatic hypotension include:

• Heart issues, including heart valve disease, bradycardia (a type of arrhythmia), heart attack and heart failure
• Endocrine problems, including diabetes, thyroid disease and Addison's disease
• Neurological issues, including Parkinson's disease and dementia
  
  

This isn't to say orthostatic hypotension is always a sign of an underlying health condition, however.

Still, it underscores why it's important to talk to your doctor if you get dizzy when standing frequently. Persistent or severe orthostatic hypotension can also increase a person's risk of falling, especially if he or she faints as a result.