I recently had a client let me know that they had to stop taking creatine because they had blood work done and their creatinine levels were high. I’m a big proponent of creatine but this is a topic that has been coming up often. Creatine and creatinine are two different things. They are related, but are not the same.
I want to be clear that I am not a doctor nor am I telling you to ever ignore your doctors advice when it comes to blood work. But it is helpful to be education on your body so you at least understand what blood work can mean for you.
Creatine is a substance created in the body that helps with energy production. It can be made in the body or consumed with certain foods or supplements. Creatinine is a waste product produced by muscle that is filtered out of the body. As more creatine is being used for energy there will be an increase in the amount of creatinine.
Some research has shown that creatine supplementation doesn’t significantly increase creatinine levels. Others show that either a higher protein diet and/or consuming creatine may lead to higher creatinine levels. While high creatine levels are a sign of renal issues, when it is the result of having more muscle mass or consuming more protein or creatine, it is not causing harm on the kidneys. It is important to realize the blood marker is not the only thing we should be looking at. It is more important to understand why that marker is high.
When you exercise, you will use more creatine to supply energy to the working muscles. As a result creatinine will build up as a waste product that your body will eliminate. This is a normal function of physiology and is not a problem at all. But when your are suffering from kidney disease, damage, or infection, they cannot properly dispose of this creatinine. This is why when blood work shows elevated creatinine it may be an issue. But high creatinine doesn’t mean kidney issues. It is one possible cause and further tests are needed.
This is why it is important to avoid intense exercise within 48-72 hours before doing blood work. If not you will have to be aware that certain blood markers will simply be elevated as a result from exercise and not necessarily from an underlying disease. This doesn’t mean ignore any out of range readings, but we should be aware of how exercise can effect certain blood markers like creatinine.
Creatinine is not the only blood marker that might be effected by working out before blood work either. Not to make it more confusing, but creatine kinase is an enzyme that is elevated after exercise. Creatine kinase occurs when there is muscle damage. This not only include skeletal muscle but also cardiac muscle. So if there is damage to the heart CK levels would be elevated. But when you exercise, skeletal muscle is damaged and will also increase CK levels.
Liver enzymes like ALT and AST measurements may also be misleading. These enzymes increase with muscle damage from exercise as well not just with liver issues.
There are many other markers that could be impacted as well based on the type and intensity of exercise performed and how soon after blood is drawn. Things like Alkaline Phosphorous, BUN, Uric Acid, Albumin, to name a few.
If possible you can resolve this by planning your workouts and blood work properly. If not you just have to keep in mind that some numbers may not represent what truly is going on in your body.
Many doctors should know about these interactions but not all unfortunately. A few years ago I mistakenly did my bloodwork after finishing a 13 mile obstacle course race. It is safe to say I had some muscle damage from the race and had blood work that really didn’t show a picture of what was normally going on in my body.
I let the doctor know about this race, but he wasn’t aware of any issues it would call and recommended I go for additional testing and even had to meet with an oncologist. Talk about a way to freak our your patients.
I would rather be safe than sorry so I went along with everything they recommended. Luckily when I met with the specialist he was quick to tell me everything looked fine and that I shouldn’t be there.
Blood markers are used to look for signs of stress and damage within the body. Exercise is stress on the body and often causes some damage. But of course there are other issues and diseases that do similar things. Hopefully you can plan your next blood draw properly so you don’t have to worry about a misreading, but just keep these things in mind.
Mike Deibler MS, CSCS
San Diego Premier Training