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What Is a Dangerous High BUN Level? + 4 Ways to Lower It

Medically Approved by Dr. Edward Salko
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Your blood urea nitrogen (BUN) levels provide valuable information about your kidneys that help diagnose diseases such as uremia and CKD. Test values beyond 20 mg/dL in a BUN test are considered abnormal and can be due to various factors.

However, a dangerously high BUN level, often starting from 50 mg/dL, indicates kidney damage that should be addressed immediately. If you have a BUN between 100 mg/dL to 250 mg/dL, it could be due to severe kidney dysfunction, specifically involving its ability to filter waste products.  

Did You Know? You can take a BUN test as an independent lab test. But it is also usually included in test panels along with other blood tests that check your overall health, like the CMP 14 blood test

What Is a Blood Urea Nitrogen (BUN) Blood Test?

Your doctor may ask for a blood urea nitrogen or BUN test as part of the lab work for assessing your kidney function. Specifically, a BUN test measures the amount of urea nitrogen in the blood. 

Urea nitrogen is a chemical waste product that the kidneys remove from the body. If this is not the case, you could be experiencing conditions like dehydration, urinary tract obstruction, or gastrointestinal bleeding. 

While BUN levels reveal critical information about your renal function, it does not warrant a direct diagnosis of any condition unless taken without the other kidney function tests

What Bun Level Is Too High

Normal BUN levels should be between 6 to 20 milligrams per deciliter (mg/dL). Beyond the upper limit (>20 mg/dL), your BUN level is considered abnormally high.  

Symptoms of High BUN Level

If your doctor suspects kidney disease, a BUN test, together with other related tests, will be requested. This can be determined by symptoms of kidney disease, which include the following:

  • Frequent urination
  • Discolored urine
  • Extreme fatigue
  • Skin itching 
  • Muscle cramps
  • Restless legs
  • Joint and bone pain
  • Swelling in hand and feet

High BUN Causes

High BUN levels indicate various medical conditions and may suggest certain lifestyle adjustments. While a BUN test helps diagnose certain diseases, especially revolving around kidney function, it can also highlight imbalances or injuries affecting blood circulation in the renal area. 


Beautiful dehydrated overworked woman feels sleepy, covers half face with palm, keeps eyes closed

While elevated BUN is often associated with kidney function impairment, it’s also possible that it could be due to chronic dehydration. 

Water plays a crucial role in waste removal – via urination, perspiration, or defecation – as it dilutes the chemical byproducts. As a result, when you’re dehydrated, BUN increases as fluid volume is low.  

In addition, creatinine (another waste product) gets altered with dehydration. Typically, your BUN/creatinine ratio should be about 10:1 or 20:1. 

Lack of water in your body will drive these numbers higher as blood flow to the kidneys gets reduced. This makes it an ideal parameter for risk prediction among patients in the emergency department.  

High Protein Diet

Dietary nitrogen mainly comes from protein. Therefore, a diet that constitutes high protein sources, like red meat, beans, fish, etc., increases your BUN significantly. In the same way, a high protein diet also elevates creatinine, tipping off the ratio for your BUN/creatinine. 

People who are bulking up and consume protein shakes are also at risk of having high BUN. Typically, a change in diet fixes this condition unless other factors play in. 

Medical Disorders (Renal Failure)

High BUN suggests kidney problems that prohibit proper function, such as in glomerular filtration. Thus, it’s often tied up with chronic kidney disease (CKD) and uremia. 

However, it could also be due to other disorders linked to decreased blood flow or volume directed toward the kidneys. These include gastrointestinal bleeding, congestive heart failure, urinary tract obstruction, diabetes mellitus, Addison’s disease, and severe burns. 

Certain Medications

Elevated BUN may not be due to any disease or medical condition. Sometimes, it can be a side effect of specific medications prescribed by your doctor. It could be from taking any of the following:

  • Rifampin
  • Tetracycline 
  • Vancomycin 
  • Methotrexate
  • Amphotericin 
  • Spironolactone 
  • Carbamazepine

High-intensity Workouts

Vigorous exercises, such as resistance and strength training, can cause damage to the muscle tissues, which increases biomarkers for kidney disease. Hence, it’s highly likely that your high BUN can be linked to constant muscle injury if you regularly engage in high-intensity workouts.

On top of this, those who spend most of their time in the gym, doing strenuous exercises, are also constantly subjected to dehydration and high protein intake. If these routines are left unchecked, they could become compounded factors for elevated BUN. 

Constant “fight or flight” response activation

When your sympathetic nervous system or “fight or flight” response is activated regularly, it leads to activities that can raise your BUN. 

For example, your cortisol (stress hormone) increases and breaks down more protein than average. Your blood circulation also gets altered, affecting the transport of waste products to the urinary system. These result in the accumulation of BUN in the kidney.

Common triggers of the “fight or flight” response are stress, anxiety, and shock. So if you’re frequently experiencing these events, make sure to have your kidney functions tested. And, of course, employ the necessary lifestyle adjustments to avoid stress. 

How To Lower Bun Levels? 4 Ways to Do It

The right action toward lowering your BUN levels depends on what’s causing the condition. While high BUN may suggest health conditions affecting your kidney, it could also be due to other factors you can correct within your means – most notably dehydration and an unbalanced protein diet. In other cases, it can be due to age-related disorders, which you can openly discuss with your healthcare provider. 

Nevertheless, here are some practical ways to lower BUN levels.

  1. Increase Your Water Intake
Young woman in fitting sport wear on bridge at hot sunny morning with bottle of water shaker thirsty after workout

If the high BUN level you got from your blood test is traced back to dehydration, it only makes sense to increase your water intake. Unfortunately, people often overlook their daily hydration due to a tight schedule or simply because it was not established in their routine. 

You can use apps that remind you to drink water or keep a bottle nearby. At first, you’ll find yourself visiting the restroom frequently, but you’ll get used to it as your body start to adjust.

How much water you should drink daily will depend on factors such as your body size, age, and kidney health, as well as environmental conditions like the climate in your area. This means the standard eight glasses of water a day may not necessarily apply to you. Hence, consult with your doctor. 

Additionally, you can track the changes in your hydration – and by extension, your kidney function – when you check your urine color. For example, healthy urine often has a yellow to deep-amber color. In the same way, how your urine smells also provides hints about your kidney function and whether or not you should hydrate more. 

  1. Limit Protein-Rich Foods

Cutting back on your protein intake can make a significant difference in your BUN levels, especially if it is the primary trigger. As too much protein can make the kidneys work twice as hard, protein-rich foods are often controlled in renal diets for those with kidney disease

Limit your intake of red meat, fish, dairy, beans, seeds, and shellfish. Likewise, if you have been taking protein powder shakes, you will have to avoid them until your BUN normalizes or as recommended by your doctor. 

On top of regulating protein in your diet, consume more kidney-friendly fruits and vegetables. These include cauliflower, cranberries, red grapes, bell peppers, olive oil, and cabbage. 

  1. Manage Your Stress

When you are constantly subjected to stress, you activate your “fight or flight response,” which alters your blood and organ activities, affecting your BUN levels. Therefore, effective stress management does not only benefit your kidney health but your overall physical and mental wellness as well. 

However, make sure to avoid common mistakes when controlling stress, like binge eating or oversleeping, as these could aggravate the condition instead of alleviating it. Know more about the unhealthy ways of coping with stress

Instead, lean more toward these practical ways to manage stress, which may help lower BUN levels.

  1. Breathing exercises 
  2. Meditation and yoga 
  3. Listening to calming music
  4. Picking up a hobby
  5. Building a work-life balance
  6. Doing light exercises
  7. Getting enough sleep
  8. Eating a balanced diet
  9. Avoiding alcohol and stimulants
  10. Spending time with family and friends

Paying more attention to your holistic wellness often helps lower your stress. Check out some of the best self-care activities you can do over the weekend to help reset and maintain optimum kidney health. 

  1. Avoid Extensive Exercise
Great exercise to have flat abs. young caucasian woman holding a deadbug press pose to exercise the muscles

Working out too much brings your BUN on the upper scale. Your doctor may recommend reducing your exercise intensity to help your kidneys function better. 

You may be tempted to withdraw from getting physical altogether, but this might cause more damage than help. So, instead, opt for light exercises within shorter time periods. Rather than heavy workouts, you can focus more on doing cardio exercises that don’t require too much work, such as walking and low-impact aerobics. 

You can also consider engaging in recreational activities that are not too physically demanding but equally fun, like water aerobics and calisthenics. Whichever activity you choose, the rule of thumb is that it shouldn’t have high intensity. 

Frequently Asked Questions: High BUN Level 

Should I be worried if my BUN level is high?

It can be worrying if you have an extremely high BUN level, say between 50 mg/dL to 100 mg/dL or even higher. These test values suggest kidney impairment, while anything higher indicates kidney failure, which could be fatal if left unchecked. 

Getting a high BUN level in your blood test can be alarming, but the danger it poses depends on its trigger. However, it can be corrected depending on what causes the BUN increase, especially if it’s simply dehydration or too much protein consumption.  

What foods can cause high bun levels?

Foods that are rich sources of protein can elevate your BUN levels. This includes red meat (beef, pork, lamb), poultry, dairy, fish, beans, etc. Limit your intake of these food items and eat more fruits and vegetables instead. 

What is the BUN level for kidney failure?

A level surpassing the BUN normal range of 6-20 mg/dL indicates kidney problems. If your BUN test shows extreme results, it might signal kidney failure. For example, a BUN level of 75 mg/dL is highly considered alarming. It may suggest immense kidney damage to the extent of possibly relying on dialysis. 

Nonetheless, other parameters should be considered to make a proper diagnosis. Hence, other tests like a creatinine blood test and albumin blood test, among others, should be taken.  

The Bottom Line 

Getting a high BUN level, whether in your diagnostic test or routine basic metabolic panel eight blood test, can be due to a lifestyle mishap or a budding kidney disease. Either way, you must let your doctor know as soon as possible. Understanding high BUN levels not only allows for accurate treatment but also routine changes that will keep your kidneys healthy and well-functioning. 

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