What Happens To The Kidneys During Exercise?

The kidneys undergo certain changes while we exercise. Read along to find out what happens to your kidneys while you exercise. 
What Happens To The Kidneys During Exercise?

Last update: 16 September, 2020

The body adapts when we exercise regularly. The kidneys also go through their own normal adaptation process due to exercise.

However, sometimes the kidneys can undergo certain physiological changes that can lead to health issues. These changes can be temporary or long-lasting and they commonly include proteinuria and electrolyte losses.

In order to understand what happens to the kidneys while exercising, it’s important to know that the organ serves the function of homeostasis. The kidneys are able to regulate the fluids and minerals within the body by producing urine.

While exercising, the body prioritizes sending blood to the muscles rather than the organs. This reduction of renal flow alters with the organ’s ability to regulate fluids and minerals.

Before understanding the changes that occur in this important organ, it’s important to know that the changes are usually harmless. Athletes undergo several changes to their bodies while exercising without it causing any health problems.

The kidneys, exercise and proteinuria

Although the presence of protein in urine is usually a warning sign, it’s usually harmless if it’s only found in the urine after exercising.

The exit of protein from the bloodstream to urine during exercise doesn’t affect the body’s metabolism and homeostasis. There’s no evidence to support that exercise can cause long-term kidney damage.

Tired woman after workout

A different kind of proteinuria can occur after strenuous exercise due to the rhabdomyolysis effect. The rhabdomyolysis effect consists of the destruction of muscle cells due to overly intense exercise. When myocytes breakdown, protein is released which is then filtered out by the kidneys. This type of proteinuria deserves attention and immediate workout routine changes.

Hematuria (red blood cells in the urine) can also be caused by exercise. If hematuria occurs without trauma to the back or abdomen, it should be taken as temporary or transitory.

Possible kidney injuries due to sports

Kidney trauma can occur with contact sports. It’s rare for a kidney to be permanently damaged due to exercise, however, it’s not impossible. If kidney damage occurs, a treatment plan is developed based on the degree of the injury that is identified.

The loss of sodium in urine is one of the most frequent disorders that can occur due to sports. Known as hyponatremia, the loss of sodium is usually associated with dehydration.

Having hyponatremia isn’t necessarily a serious issue. However, the risk increases if it’s combined with intense exercise without electrolyte replacement. Marathoners are quite familiar with this disorder that’s why they pay special attention to hydration while competing.

What about people with kidney issues?

Considering all that we mentioned above, it’s logical to ask whether chronic kidney patients can practice sports? The answer is yes. They can perform the exercises that their doctors permit.

One of the main risks that chronic kidney patients face is their increased cardiovascular risk. Mortality is usually not caused by kidney failure but rather by the heart not being able to stand the kidney’s poor filtration. Physical exercise in moderation can reduce overall mortality.

couple walking

When it comes to kidney stones, sports are completely contraindicated when the patient is having a pain crisis. In these cases, it’s best to treat the pain before starting to exercise.

Finally, when it comes to patients who are undergoing dialysis ( filtering urine with an external dialyzer machine) the good news is that certain exercise routines have been developed to perform both during and between dialysis sessions.

The changes that occur in the kidneys due to exercise isn’t pathological

In conclusion, changes to the kidney’s physiology during exercise should be expected for the most part. When exercising, the body adapts and responds to the activity. You should only be alarmed if you present severe signs.

If you have any doubts about your kidney function or have noticed changes in your urine, consult your doctor.


All cited sources were thoroughly reviewed by our team to ensure their quality, reliability, currency, and validity. The bibliography of this article was considered reliable and of academic or scientific accuracy.


  • Rigueira, P. Vázquez, et al. Efectos de un programa de ejercicio intradiálisis en pacientes con enfermedad renal crónica. Revista Iberoamericana de Ciencias de la Actividad Física y el Deporte 8.3 (2019): 52-66.
  • Montero, Álvaro Morente, and Francisco Jesús Llorente Cantarero. Hidratación y deshidratación en la Actividad Física y el Deporte. Wanceulen Editorial SL, 2020.
  • Traiperm, Natthapon, et al. Energy metabolism, liver and kidney function in adolescent marathon runners. European journal of clinical investigation 46.1 (2016): 27-33.
  • Lipman, Grant S., et al. Incidence and prevalence of acute kidney injury during multistage ultramarathons. Clinical Journal of Sport Medicine 26.4 (2016): 314-319.

This text is provided for informational purposes only and does not replace consultation with a professional. If in doubt, consult your specialist.