How much and what kind of physical activity is appropriate when you have kidney disease, and what can cause lab values to worsen after exercise? In this post, I walk through why circulation is key from the kidney’s perspective, when creatinine and eGFR can be misleading after a workout, and why stress and the state of the gut microbiome are also part of the picture. If you’re unsure what level of exertion is safe in your situation, it’s worth watching the video or reading the transcript.
The content of the video in written form
Hello, this is Dr. Zsom. Dear patients!
Well, exercise protects the circulation, including circulation within the kidney. Exercise is a natural life function, and whatever is natural is going to be protective for the circulation, so it’s going to protect the kidney as well. So the short answer to the question “what does exercise do to the kidney?” is to improve kidney function and to prevent kidney disease. But let’s talk about this in a little bit more detail.
So exercise is a natural life function, and it is also a natural reaction of the body to stress, even chronic stress. So if you don’t do enough exercise, especially when you are under a lot of stress, that’s gonna hurt your circulation. And we are gonna learn during the second half of this presentation, it’s gonna also harm your gut flora, the bacterial flora within the bowels.
So exercise does not lead to kidney overexertion. So when you want to hurt your kidney, it’s not by doing exercise. It’s by taking too much salt and fluid and eating too much animal proteins. And those will overexert the kidney. They are a great burden in terms of kidney function. Exercise also induces sweating, and by that, exercise removes excess salt. So it’s very important to understand that exercise is also part of detoxification, removal of toxins, salt being one of the toxins that the exercise is removing.
So the kidneys in general love oxygen, therefore a good blood supply needs to be maintained, oxygen deficit prevented. So if you want to wash your kidneys, the most important thing is to maintain a good circulation, and you don’t do that by drinking a lot of fluids. You do that by other means. Let’s talk about it.
So for instance, aging causes hardening of the arteries. The blood supply may decline in several organs, including the kidneys. So the kidneys slow down. They will scar and shrink. But since hardening of the arteries is a patchy disease, it’s a little bit more here, less here, so one of your kidneys will shrink more than the other, and you have an asymmetrical size of the kidneys, so that you can recognize this problem during the ultrasound examination.
So the kidney protective agents, such as ACE inhibitors and others, will aggravate this problem, and of course nonsteroidal anti-inflammatory agents, so pain medicines of the inflammatory kind, they aggravate the situation. Why? Because they further reduce blood flow. And so far as you are young and healthy and you don’t take a lot of these medications, it might not be a problem. But when you are old, you have hardening of the arteries. If you take these medications, they can decrease your kidney function quite substantially.
So the kidney protection can be harmful? Oh yes, we already talked about it. When you are dehydrated, for example because of diarrhea or whatever, these medications should be paused, and diuretics and certain blood pressure medications as well. But in the elderly, when hardening of the arteries is common, these medicines are very often used, and most of the family doctors will not understand that they have these side effects of decreasing the kidney function, precisely because they decrease circulation of the kidneys. So if there is doubt about this, a nephrologist should be consulted.
But can exercise be harmful? Yeah, well, anything can be harmful if it’s taken to an excess. So when you have extreme exercise in a boot camp or just you run the marathon or whatever, yeah, exercise could cause dehydration and muscle damage. And by damaging the muscles, certain substances get produced which then can hurt the kidney. So too much exercise definitely can cause harm. This is not to be mixed up with the fact that when you have some moderate amount of exercise immediately before a blood draw, then the lab results can be also influenced without harming the kidneys. So you have a higher creatinine, you have a lower eGFR, not because your kidney is worse, but because more creatinine is produced out of which you calculate these things. So it’s not very advisable to do a lot of exercise immediately before a lab test.
So here’s a new concept for you: blood vessel damage, bad circulation causes organ dysfunction in every organ, including the kidney, and this is the leading cause of kidney damage. So again, much of what we think is kidney failure of unknown cause actually has a cause, and that is blood vessel damage.
So what can cause blood vessel damage on the long run so that the kidneys are affected? Well, excessive salt intake, organic acids such as in excessive amounts of meat, chronic stress which is not handled by exercise, saturated fats, animal protein in excess, so too much meat, refined industrial sugars, preservatives, so this kind of preservatives as well, baby formula, and lack of exercise. And again, stress, lack of exercise, salt intake, they are very closely connected.
So the kidney is especially sensitive, needing a lot of oxygen, so it needs a good circulation. So it’s very important to keep your circulation intact. So unfortunately, in a highly developed industrial societies, you have a problem. You have a problem with lots of industrial sugars and preservatives, lack of exercise, too much salt and saturated fatty acid intakes, chips with a lot of salt, again lack of exercise, and all kinds of fast foods which have all kinds of bad things.
And if you look at chronic kidney disease frequency per million inhabitants, then you will see that these industrial societies are leading in terms of frequency of chronic kidney disease, and it’s because stress is not handled appropriately by exercise. It’s handled by too much consumption.
So this is our own presentation. It was in Hungarian in a Hungarian nephrology meeting, and so we compared data in a Hungarian dialysis unit versus an American dialysis unit. And this is in Hungarian, but I’m going to translate it for you. And you see that mortality, you know, is how many patients died during a year. It was much higher in the American dialysis station, that is the center. They were more hospitalized. They spent more days in the hospital than the Hungarian ones. Now why is that? Because by that time, now this is an exception, that’s African Americans, but by that time they got to dialysis, they already had a lot of circulation damage. Now in African Americans, the situation is different because they tend to unfortunately develop kidney failure even when their blood vessels are relatively intact. In other words, the circulation is less impaired, less diseased.
So what we see here, that in the American dialysis center, and this was done in 2007, type 2 diabetes, which is clearly a disease which has a lot to do with lifestyle and stress not handled well, was much higher than in the Hungarian unit. Unfortunately, the Hungarians are catching up.
So what can we conclude from this? We can conclude that it is extremely important to keep your circulation intact.
Muscle pump had circulation. So if you use your muscles, then your circulation is going to be better. It is circulation that washes through the kidney tissue, not excessive water. So good blood supply is necessary to wash through all the organs or the tissues, and the kidneys are especially sensitive to bad circulation. So the heart is also a muscle, and the heart pump also increases its capacity during exercise. So when you do not do exercise, you do not exercise your heart either. So that the kidney gets less blood if you don’t do exercise and more blood when you do exercise. So is it important? Yes.
So it is exercise that provides real cleansing of the tissues, not water, water intake. So what causes detoxification, removal or handling of toxins in general in the human body? It’s the kidney, the liver, the bowels. We’re going to talk about bowels quite a lot in the second half of this presentation, and sweating. If you analyze sweat, there is quite a bit of sodium in it and other poisons and problematic substances.
So in extreme cases, you can sweat 10 to 14 liters per day. I don’t encourage you to do that, but there’s that capacity with a spoonful of salt removed, which corresponds to two-thirds of a liter of blood salt content. So you can remove quite a bit of salt by exercising, and if you have too much salt in your body and the decreased capacity to remove salt, for example because you have kidney failure, then it should be quite important to sweat. And what do you have to do for sweating? Exercise, of course.
Caution, right? I mean, if you overexert yourself, that’s not going to be good, especially if you already have heart failure, and don’t try sauna because that can be a problem. I mean, you can have a really bad blood pressure problem. You can collapse and all kinds of bad things can happen. So it’s not excessive heat that’s gonna be your friend, but moderate amount of exercise.
So ultimately, exercise removes poisons from the body because it consumes excess carbohydrates and fats. So when you accumulate too much carbohydrates and fats, that’s not going to be good. It’s going to change your immune system and it’s going to change your endocrine system. Yeah, too much hormones, insulin and others, which gonna further hurt your circulation.
Exercise improves circulation in several organs, including the kidney. It removes poisons during sweating, including excess salt. It causes euphoria. It causes joy. Why? Because it’s a natural human function, and what is natural is good. Sorry that I have to stress that, but we live in an age where it needs to be stressed. So it helps with stress handling. If you are chronically stressed, it’s not consumption that’s gonna help you. It’s doing your natural function of life, including exercise. In the long run, it protects blood vessels. It helps keeping the lungs clean, so that you have less infections in the airways, specifically. It protects the kidney through several mechanisms, keeping the blood circulation in the kidney adequate, even in dialysis patients where circulation is often already impaired. It has been shown that exercise is one of the lifesavers. So besides chocolate and some medications, it’s primarily the exercise that can prolong your life, not to mention life quality. You can have quite a bit of euphoria and life quality changes.
So now let’s talk about gut flora. In other words, one important participant in how exercise and diet and the kidney function work together. So the gut flora is a true symbiont inside the human body since forever. So it’s an ancient alliance between a lot of bacteria forming a system, a bacterial system, and the human body. They cannot live without each other. They have to cooperate.
There are more than a hundred trillion bacteria living in the human gut. This is more than the number of cells in the human body, so this is extremely important. And why do we not talk about this? I don’t know. We should. Although the gut flora is mainly composed of bacteria, there are also other microorganisms present, but the best studied organisms are bowel bacteria.
A healthy balance inside the gut flora is crucial for the healthy functioning of the kidney, the brain, the lungs, the heart, platelets, and the immune function, the immune system. So it’s that important, really, and yet we don’t talk about this. It’s a mystery.
So well-established basic functions of the gut flora include digestion of carbohydrates. Now again, the more complex carbohydrates, the more natural, because natural is complex, all right? So more natural carbohydrates, the more the gut flora helps to digest these carbohydrates slowly, gradually, causing insulin regulation to be perfect, preventing diseases of the gut. You need to have a good gut flora so that you can maintain bowel health. Regulation of carbohydrate synthesis inside the liver, regulation of immune function and clotting, digestion of fats, degradation of protein, production of vitamin B and K, decreased production of uremic toxins, toxins that are produced in kidney failure, in chronic kidney disease. So when you have a healthy gut flora, you have less of these poisons produced by bacteria. Less production of this means that you will have less poisons that the kidney is supposed to remove and often cannot because of chronic kidney disease.
So the gut flora also has an important role in brain function and mood disorders, depression, for example. So there is a so-called gut-brain axis where gut and brain work together. And if this cooperation is not working out, then you get depressed. Prevention of inflammatory diseases in the lungs. This is the so-called gut-lung axis. There is an interaction between gut and lungs, and if you have impaired gut flora, then you tend to have more of these inflammatory diseases relapsing. Metabolism of medications and other chemicals, so it’s not just your liver and kidney, but also your gut flora, and production of antioxidants. So if you eat bad things, if you don’t exercise, if your circulation is not good, a lot of oxidants are going to be produced, free radicals, for example, and those will damage your circulation. And if you have antioxidants, that will protect you to some degree.
So what can damage the gut flora? Well, cheap industrial refined carbohydrates, saturated fatty acids, preservatives, and excessive salt intake. And here’s another one: chronic stress. So if chronic stress is not handled, because you don’t exercise when you are stressed, but you consume when you have stress, then your gut flora is not gonna work properly. Antibiotics, especially wide-spectrum antibiotics, if they are taken for too long without probiotics and protective foods such as, for example, yogurt. Impaired circulation in the gut, especially in the context of heart and kidney failure, causing bowel edema.
So here’s what happens. If you have impaired circulation, especially if you have heart and kidney failure, then the bowels are not going to function well, because the bowel wall will swell. And if it swells, that means that a lot of poisons can go through from the bowel into the blood, and you will be full of poisons. Viral infections, including COVID, they can impair the normal functioning of gut flora, or any kind of inflammation inside the bowel, for example in certain autoimmune diseases.
So once the gut flora is damaged, we call that dysbiosis. So dysbiosis means that the bacteria don’t produce what they are supposed to produce and they produce poisons instead, and the gut flora doesn’t function well. So various different poisons can be produced that accumulate in the context of chronic kidney disease, and diarrhea. You can have quite a bit of diarrhea if your gut flora doesn’t function well. Bacteria produce poisons called endotoxins. And this is an error here, so it’s endotoxins. These are naturally produced even by good bacteria, but normally they are not absorbed through the bowel wall. But if the bowel wall is inflamed or there is a swelling of the bowel walls, then these get absorbed into the circulation and will cause inflammation of blood vessels. Platelet dysfunction, decreased immune response, blood clots, impairment of the blood-brain barrier protecting the brain, brain dysfunction, chronic depression. These can all be a consequence of dysbiosis.
So how can we prevent it? Well, you guessed, by eating the right thing and by exercise and avoid eating certain things. So let us avoid unnecessary use of antibiotics and just take them as long as they are absolutely necessary. Always take probiotics, yogurt, kefir, and probiotics with antibiotics. Eat healthy, fiber-rich, fresh, natural foods. Again, like I said, what’s natural is good. So natural foods are rich in fiber, and they will aid the maintenance of normal gut flora. Unsaturated fatty acids, natural carbohydrates. Remember, preservatives are low-dose poisons. So if you eat fresh things, then you have less poisons in your body, right? This is not fresh.
Dysbiosis, how can we prevent it? Well, let us avoid hypervolemia. So if you have too much salt and water in your body, especially if you have kidney and or heart failure, you have a problem with bowel wall swelling, and so your gut flora is not gonna function well. So if you have heart or kidney failure, then salt and water, salt and any kind of fluid, will need to be restricted. Let us protect the circulation of the gut. Exercise, regular eating, blood sugar control, natural fats, and as little industrial foods as possible. And let us handle stress with exercise, not with consumption.
Now, industrial things have their own logic. So pour more oil and saturated fatty acids there. They can be stored easily and they can be transported easily. But that’s not what you want. What you want is natural fats.
So with that, let me just promise you that next time we’re going to talk about diet in general, and I’m gonna give you dietary tips that you won’t hear in very many other places. But for now, thank you for your attention and goodbye.
