IV drip infusions present the fastest way to rehydrate and regain lost electrolytes. These were typically used for patients who were sick and dehydrated. However, nowadays IV therapy is used by people looking to improve their health, feel better, or to get over a hangover. IV therapy delivers fluids, electrolytes, minerals, and vitamins that help replenish your body.

But, how long do these IV fluids actually stay in your body, and what happens when they wear off? The sections below provide answers to these questions.

How Long Do IV Fluids Stay in the Body?

IV fluids generally remain in your body for a couple of hours after absorption. That said, the nutrients and minerals present in the fluids may remain in your body for days, weeks, or even months. This significantly depends on your body's needs and the type of IV infusion you receive.

Several vital factors and biological processes affect how long IV fluid is retained in your body. They include:

Hydration Level

How long your body retains fluid from an IV infusion all comes down to your base hydration level. If you are properly hydrated, your body passes out the additional IV fluids it doesn't need more quickly. However, if you are dehydrated and get an IV fluid infusion, your body will retain most of the IV fluid.

Illness

Certain biological processes and illnesses affect how long IV fluid remains in your body. Conditions like kidney failure, diarrhea, vomiting, and excessive sweating cause you to lose lots of water in a very short time, thus resulting in dehydration. You may also get dehydrated from taking medications that contain diuretics.

Getting an IV fluid infusion while dehydrated means that your body will retain most of the IV fluid since it only eliminates what it doesn't need. That said, the beneficial effects of the electrolytes and minerals present in the fluid last long after your body passes out the fluids. 

Metabolic Rate

Your basal metabolic rate (BMR) can simply be defined as the number of calories you burn as your body performs its basic life-sustaining functions. Most Americans’ BMR ranges between 1400 and 2000. This basically means that they only need to take between 1400 to 2000 calories per day to fuel their body's basic functions when in a resting state.

Your basal metabolic rate affects the rate at which your body absorbs nutrients from fluids. It also affects how quickly the excess fluids are passed through your system. People with a high metabolic rate typically absorb nutrients from IV fluids quicker. They also pass them out faster than people with a low metabolic rate. 

You may excrete IV fluids slower if you have a low metabolic rate due to old age or weight gain.

What Happens After IV Fluids Leave Your Body?

IV therapy delivers water, amino acids, minerals, and vitamins at a controlled rate. The procedure typically lasts between 45 minutes to an hour. That said, the procedure can be done more quickly or even take longer, depending on why you are undergoing the IV therapy.

The effects generally kick in in a short time but may take longer if you are heavily dehydrated. After the infusion, the effects may last anywhere from a few hours to a few days. Even after the IV fluids leave your body, you still benefit from the electrolytes and minerals in the fluid.

Can You Retain Too Much Water From an IV Treatment?

Your body generally passes excess fluids after it takes what it needs. However, too much IV fluid in your system can result in hypervolemia, especially if you have other underlying conditions. Also, according to a study, too much IV fluid during and after surgery is associated with hypervolemia. 

You should, however, note that you can only get hypervolemia during the infusion process. Afterward, all excess fluids leave your body through normal metabolic processes.

How Long Does It Take for Swelling to Go Down After IV Fluids?

Swelling generally occurs when IV fluid leaks out of the vein into the surrounding soft tissue. The common signs of IV fluid leakage include inflammation, pain around the IV site, and skin tightness. As long as the site is not infected, the swelling generally decreases after a few days.

If you swell up after getting an IV fluid infusion, you can treat the inflammation by:

• Elevating the IV site as much as possible. This helps disperse the fluid faster, thus reducing swelling.
• Applying a cold or warm compress for 30 minutes every two to three hours after the infusion.
• Medication. If the IV fluid is vesicant (irritating the tissues), your doctor may recommend medication 24 hours after the infusion.

What Is the Difference Between Absorbing Fluids Through IV Infusions and Drinking?

Your body retains and passes IV fluids differently from the fluids you obtain by drinking. An IV drip infusion does the following:

• It provides water and other essential nutrients directly to your bloodstream, thus making them more accessible to your organs and body cells.
• Unlike drinking, IV drip infusions don't force water through your digestive tract. This means that you get to retain the minerals and electrolytes that would otherwise be lost to the digestive process.

If you drink water or other supplementary beverages, it has to pass through your digestive system at a static rate. This means that you can't slow its movement once you swallow it. Moreover, the minerals and nutrients in swallowed fluids may also be partially eliminated or compromised by your digestive system. 

On the other hand, since IV fluids are injected directly into the bloodstream, there is no chance of the nutrients being destroyed by the acids in your stomach. You'll also see the benefits much quicker than you would from drinking the fluids.

The Bottom Line

Although IV fluids stay in your body for a few hours, their benefits last long after the fluids are passed from the body. They also present a more efficient way to get rehydrated. IV drip therapy caters to various needs ranging from hangover recovery, immune system support, and gut health improvement.