Medical causes of fatigue Some common causes of fatigue include: 1  Anemia â When you have low red blood cell counts in your bloodstream, your body has to work harder to deliver oxygen to your cells, causing fatigue.2  Iron deficiency is also associated with fatigue. Anemia â When you have low red blood cell counts in your bloodstream, your body has to work harder to deliver oxygen to your cells, causing fatigue. 2  Iron deficiency is also associated with fatigue. 3  If you're diagnosed with anemia, then it's important to understand the cause in order to correct the problem.
Occasionally, a health practitioner will look at the ratio between a person's BUN and blood creatinine to help determine what is causing these concentrations to be higher than normal. The ratio of BUN to creatinine is usually between 10:1 and 20:1.An increased ratio may be due to a condition that causes a decrease in the flow of blood to the kidneys, such as congestive heart failure or dehydration.ccasionally, a health practitioner will look at the ratio between a person's BUN and blood creatinine to help determine what is causing these concentrations to be higher than normal. The ratio of BUN to creatinine is usually between 10:1 and 20:1.
When your BUN levels are compared with your creatinine levels, it gives a fuller picture of whatâs happening with your kidneys. This is known as the BUN/Creatinine ratio. Creatinine is a waste product from your muscles that is also filtered by your kidneys. Like BUN, high levels of creatinine could mean there is a lot of waste product that hasnât been removed by the kidneys. The ideal ratio of BUN to creatinine falls between 10-to-1 and 20-to-1. Having a ratio above this range could mean you may not be getting enough blood flow to your kidneys, and could have conditions such as congestive heart failure, dehydration, or gastrointestinal bleeding.