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What your doctor doesn't know about training with weights

Was Dein Arzt nicht über ein Training mit Gewichten weiß

Sir William Osler, the founder of modern medicine, once remarked "The greater the ignorance, the greater the dogmatism."

It's kind of ironic that modern medicine is so ignorant - and so dogmatic - when it comes to exercise and nutrition. It's not hard to see where this comes from. Pride. Presumption, even.

Medicine is one of the most challenging scientific fields. After 8 years of study, I take my Hippocratic oath within a few weeks. And then I still have 6 years as a junior doctor ahead of me. Some of my fellow students took even longer. That's a lot of time, a lot of learning and a lot of effort. And the responsibility? We make decisions every day that can mean the difference between life and death. Every time we examine a patient, we have the chance to see - or miss - a sign or symptom of a disease that could cost our patient their life or irreparably damage their health. We are among the best and the brightest, the best educated and the most influential people in the world. It's hard not to let that go to your head. At the end of the day, medicine is all about authority and knowledge. We know more about the human body in terms of health and disease and have more responsibility for it than anyone else.

Compare this to science, which is ultimately about ignorance. Science moves forward when we take a look at what we don't know and try to figure it out.

Needless to say, finding ignorance is one of the most important lessons a scientist can learn. In fact, you could say that this is the only job of a scientist. Doctors learn a lot about what science has discovered about the human body. But they are not trained to be scientists, or to think like scientists. A doctor knows what he knows and that's all there is to it.

Doctors have a lot of opinions on diet and exercise. Training with weights is not healthy. Working out with weights will damage your heart. You will ruin your joints. Squats are bad for your knees. Deadlifts are bad for your back. You should only train with light weights and high repetitions. You are too heavy and will die of a heart attack or diabetes if you don't lose weight. You are destroying your kidneys with all that protein. Creatine is bad for you. The only workout you need is cardio. I could go on for days. Most of us have heard it before. And many of us don't pay much attention to such statements. Some of us do and change the way we exercise. And almost all of us wonder how true these statements really are and whether we are destroying our bodies in our pursuit of strength and physical perfection. The real question, however, is how much attention should we pay to these experts?

As I've said before, medical education is extremely intense and extremely broad. It has to be. But there is also a lot that is not covered by this training. We learn the molecular structure of every amino acid (and most of us forget all about this after the biochemistry exam). We learn the equations for cardiovascular physiology. We learn the branches of every nerve and the origin and insertion point of every muscle in the human body. But we don't even learn the basics of healthy eating. We learn nothing about the adaptations of the cardiovascular and muscular systems in response to exercise. We don't learn about how insulin promotes the use of protein and creatine. We don't even learn what all the muscles in the human body actually do. We don't learn about the difference between myofibrillar and sarcoplasmic hypertrophy - or the training effects of high repetitions versus low repetitions. Heck, most doctors aren't even aware of the concept of high-intensity interval training - let alone how much more effective it is than steady-state cardio.

And yet doctors think that your opinion on proper nutrition and training actually matters. I honestly don't know whether to laugh or cry at this. All those years of training and everything I know about training and nutrition, I had to teach myself. And most of my colleagues don't even understand why I make such a big deal out of it. There's no other way to describe all of this than pathetic. In this article, I want to address some of these issues that doctors get completely wrong - sometimes because of ignorance when it comes to exercise physiology and nutrition, and sometimes because they don't know the limits of their own knowledge.

The following are just a few examples of things doctors get wrong with strength athletes:

Body composition

If you go by BMI, most serious strength athletes are overweight or even obese. There are a lot of dramatic studies out there about the health risks of being overweight, ranging from heart disease to stroke to cancer to dementia. I don't think this is a point where there is much ambiguity. Being fat is bad for you. The real question is whether BMI is a useful tool to gauge how fat you are. It seems like every time I go to the doctor, he (or his receptionist) mentions my BMI of 29 and tells me to lose weight.

Now, to be honest, it's been a while since I last saw the bottom row of my six-pack and my love handles have names of their own, but if I didn't have such well-defined glutes, my 32-waist jeans would slide down unhindered without a belt. I'm pretty sure that my "incipient obesity" has more to do with the fact that I barely fit into my size 56 jacket than with a dangerously high body fat percentage.

When a muscular person brings up this topic, doctors often respond something along the lines of "Okay, this system doesn't work for people with a lot of muscle, but it works fine for the average population."

Does it? Does it really? I have my doubts. Ultimately, BMI is based solely on height and weight and ignores everything else like bone structure and lean body mass, which can vary widely even within the so-called "normal" average population.

Some scientists at the Mayo Clinic had their own doubts - and with good reason, as it turned out (1). When they used the diagnostic power of BMI using the WHO's reference standard for obesity for men (25% body fat) and women (35% body fat), they found that only 36% of all obese men had a BMI of over 30. The majority of people who were carrying around unhealthy amounts of fat had a normal BMI or a BMI in the "overweight but not obese" range. And as if that wasn't bad enough, it turned out that in people with a BMI below 30, this correlated better with lean body mass than with body fat percentage. A study by another group of researchers from Canada came to similar conclusions (2). So using BMI doesn't really work well for the "normal" population either. As if not managing to identify two-thirds of people who need to lose weight wasn't bad enough, it also means that decades of population studies regarding the health risks of obesity are largely invalid.

Most people with a BMI over 30 are indeed obese. But nearly half of the American population with a BMI under 30 is also obese. This means that most of these studies drastically underestimate the health risks of obesity. This is not a concern for those of us in the MMA, lighter weight classes or figure class athletes. But for all the bodybuilders and strongmen out there who are carrying around a significant amount of adipose tissue, it means those extra pounds are more dangerous than your doctor would think.

The last thing I want to talk about is lean body mass. A lot of studies have found what many doctors consider the "paradoxical" effect. This says that people with a BMI in the overweight range (25 to 29.9) tend to live longer, have less heart disease, have a better chance of surviving cancer and suffer from fewer disabilities.

Studies that have compared BMI with body fat and lean body mass have concluded that people in the overweight range (but below the obese range) were not necessarily fatter than people in the so-called "normal" range, but that the extra body mass was more likely to be lean body tissue. Contrary to what your doctor might tell you about all the extra muscle mass you're carrying around, your training with weights is probably doing more for you than all that running does for a marathon runner.

But that doesn't mean that a greater amount of lean body mass doesn't have its drawbacks. Injuries occur when you push yourself hard and to the limit in the gym. This extra body mass and heavy weights put more strain on your joints, although this is balanced out by your muscles carrying more of the load and your connective tissue carrying less. The more weight you carry around, the harder your heart has to work.

More muscle means a faster metabolism and therefore a lower risk of dementia, diabetes and heart disease. But it also means more free radicals and potentially more inflammation, which means more stress on your endocrine system, your cardiovascular system and your brain, and possibly a higher rate of cancer. So is there such a thing as a point of diminishing returns? Is there a point where you have too much muscle mass? Maybe. But since population-based long-term studies have only ever used BMI, we don't know.

BMI is out of date and doesn't really serve its purpose - and not just for muscular people, but for everyone. You wouldn't let someone deadlift with their knees bent and their back round, and you shouldn't let people determine their own health status and weight loss goals based on BMI. Tell these people to use a body fat scale or get a skinfold measurement or a DEXA scan instead. Something so ingrained and so insidious needs to be attacked at every level by every person who knows better. Spread the word.

High blood pressure

High blood pressure is one of the most widespread chronic diseases. And even if there are no symptoms, high blood pressure can have devastating effects on your kidneys, brain and heart (3). This is why high blood pressure is considered so insidious - and also why doctors almost always check blood pressure regardless of the reason for your visit.

The time, resources and intensity with which the medical community attacks the problem of high blood pressure is entirely justified, but just as with BMI, our method for measuring blood pressure is less than perfect (albeit worlds better). If you really do have high blood pressure, then it is very important that it is treated. But what if it isn't? Whether it's the inconvenience, the cost or the side effects, no one wants to pop pills if it's not necessary. More pragmatic concerns have to do with private health insurance, where diagnosed health conditions existing at the time of taking out a policy can drive premiums up sharply, or even result in a rejection. The last thing you want in this area is to have a diagnosis of "high blood pressure" haunting your medical records for all time.

But back to measuring blood pressure. The only accurate way to measure blood pressure is to insert a catheter with a pressure gauge on the tip through an artery into your aorta. Not very practical - and not very fun either. This is the reason why doctors use a blood pressure cuff.

However, in really seriously ill people, blood pressure is also often measured using a catheter. In my limited experience as a young doctor, the readings from an arm cuff are consistent with direct intra-arterial blood pressure readings. But this is not always the case.

The cuff itself is a possible source of error. A cuff that is too small will measure values that are too high. A standard cuff is suitable for an upper arm circumference between 36 and 38 centimeters. But most people for whom we doctors use larger cuffs are usually quite overweight to obese.

It often doesn't occur to many doctors that a slim arm might simply be too big for a standard cuff. Even if you tell them beforehand that the standard cuff is too small, they often insist on trying this one first. For me, this cuff usually either fails completely when it comes to taking a reading or gives such an absurd blood pressure reading that the doctor gives up and uses a larger cuff. For many, however, where such a cuff is only slightly too small, this cuff will give readings that would be expected in a person with high blood pressure. This is a false positive. If I were you, I would ask the doctor to take a measurement with the larger cuff if the standard cuff gives a high reading.

The second problem is related to the fact that you have muscle and fat surrounding this artery, so the value measured by the cuff is a result of how the pressure from the artery is transmitted through fat and muscle. Fat, which is very compressible, can act like a sponge or shock absorber and lead to falsely low readings. I once had a patient who was so extremely obese that no one in the office was able to take a useful blood pressure reading on the upper arm. We ended up having to use the forearm. Muscles, on the other hand, are very tight and can lead to higher values than expected.

This is known as 'spurious systolic hypertension' (SSH) (4). In most people with high blood pressure, both the upper (systolic) and lower (diastolic) values are elevated (systolic >140 and diastolic >90). Some people suffer from what is called "isolated systolic hypertension" (ISH). In these people, only the upper value is elevated. This is most commonly seen in older people and we doctors believe that this is because the arteries of these people are no longer as elastic as in younger people due to calcium deposits on the walls of the arteries.

People who suffer from "false high systolic blood pressure" tend to be younger and not have major risk factors for health problems (obesity, smoking, high cholesterol) - in other words, not the people you would normally see "isolated systolic hypertension" in. They tend to differ from people with blood pressure in the normal range of the same age only in that they have a higher BMI and are more likely to exercise (5). "Unreasonably high systolic blood pressure" most likely has nothing to do with blood pressure and everything to do with the anatomy of the muscles in the person's arm.

So if you are diagnosed with high blood pressure, you should first check the size of the cuff and then look at the diastolic value. If this is below 90, there is a high probability that it is a case of "non-genuine high systolic blood pressure" and that you do not need medication.

Kidney function

It is a common dogma among doctors that a high protein diet is bad for your kidneys. As this topic has already been discussed extensively in numerous other articles, I don't want to go into too much detail here. The bottom line is that high protein intake may or may not be bad for your kidneys. We simply have no scientific evidence to suggest one or the other. However, this also means that your doctor has no scientific basis for telling you that you are destroying your kidneys. The idea that protein is harmful comes from studies done on people who suffered from kidney damage - people who suffered from either chronic renal insufficiency or chronic renal failure. For these people, there is no doubt - the higher the protein intake, the faster the deterioration of their kidney disease.

This makes sense when you think about it. These are people whose kidneys can't even cope with the basic demands their bodies place on them. Increasing the demands on the kidneys beyond this basic status cannot possibly be good. But can we apply these observations to people with normal and healthy kidneys? There is no reason to think that we can and plenty of reasons to think that we can't.

The kidneys are amazingly robust organs with a lot of excess capacity. In fact, you have to lose about 75% of the functional units (nephrons) in your kidneys before a kidney function test will show any changes. And that doesn't even take into account the fact that the kidneys can dramatically increase their filtration rate in healthy adults compared to resting levels. An analogous situation can be observed in the heart. In a healthy adult, HIIT or any kind of cardio training is good for the heart. But take a person who suffers from heart failure or serious coronary artery disease. For such a person, it's probably not a good idea to start with sprints up the stairs. This is also the reason that all erectile dysfunction medications have warnings on them that the user should ask their doctor if it is safe for them to have sex. If you take an already weakened heart and strain it, bad things can happen. But is that why you see doctors recommending that healthy people abstain from exercise?

Our next concerns about the kidneys are the blood tests that doctors do to determine how well the kidneys are functioning. There are two values that we are particularly interested in: The blood urea nitrogen (BUN) value and the blood creatinine (Cr) value. Blood urea nitrogen (BUN) is a waste product of protein metabolism. Creatinine is a breakdown product of creatine phosphate, which is found in your muscles, heart and brain. Doctors usually examine these levels using a simple blood test that shows them the concentration of both. And this is where things get tricky - and these are exactly the places where doctors can make wrong assumptions. The concentrations of these substances in your blood are affected by several factors, one of which is kidney function. The BUN concentration changes with your hydration status (low if you are well hydrated, high if you are dehydrated).

It also changes in response to too much protein that you consume and metabolize. The more protein you consume, the higher your BUN value will be. Creatinine levels, on the other hand, are much more stable. Creatinine is produced at a relatively constant rate - due to the constant process of muscle breakdown and rebuilding, more or less depending on how much muscle mass you have.

So the concentration in your blood has a lot to do with how much lean body mass you have. Having said that, it should be mentioned that there are certain things that can increase your creatinine levels. Serious infections or other stressors increase muscle breakdown as a consequence of cortisol and pro-inflammatory hormones circulating in your body. For the same reason, a particularly intense training session or competition can also greatly increase creatinine levels. There is a "normal range" for each of these levels. And people who have BUN and Cr blood levels outside these ranges often suffer from kidney problems. On the other hand, there are a lot of strength athletes who also have abnormal levels on these blood tests, which can cause them and their doctors to panic.

But these "normal" ranges are based on the assumption that you are also "normal" when it comes to all the factors I talked about earlier. A higher protein intake means a higher BUN blood value. Higher lean body mass means a higher blood creatinine level. Higher physical stressors (and a resulting increase in creatine turnover) means higher creatinine levels. Do you think any of these factors could apply to strength athletes? Damn right they do.

So the results of your blood test come back and your kidney values indicate possible problems. Your doctor will call you in a panic and tell you that you've destroyed your kidneys with all that protein and creatine and that you need to stop immediately. What do you do in a situation like this?

Well, your doctor has simply overextended himself. He really has no idea how your kidneys are doing and neither do you. But that's not a problem, because we doctors have the tools to directly calculate how well your kidneys are working - we just don't use them very often. It takes a urine sample. A bloody urine sample. The only way to find out if your kidneys are filtering waste products well enough is to see how much of it they are excreting. Sounds like common sense, doesn't it?

What I would do is ask for a creatinine clearance measurement. You will have to give up training for a few days, which will reduce your creatine to the baseline level of simple muscle turnover, but I wouldn't stop taking protein and creatine.

After you've given your body enough time to clear any possible stress-related increase in creatinine production, you'll come back for another blood test and urine sample. The lab will compare your creatinine blood concentration with the amount of creatinine in your urine. This will tell your doctor exactly how well your kidneys are excreting waste products and allow him to investigate all the ways in which you are "abnormal". As I said, it could turn out that your kidneys really are in bad shape, but more likely it's just the fact that you eat more protein and have more muscle mass than most.


Einstein once said "It is in no way a waste of time if we become practiced in analyzing from our own experience general concepts long held to be valid and in showing the circumstances on which their validity and usefulness depend and how they have evolved. This will break their excessive authority." You wouldn't be here if you didn't take your health seriously. This and your love of iron make you abnormal, which means that sometimes you don't fit the model that other people use to judge you - whether it's thinking you're a mindless powerhouse or determining the state of your health. It's important to understand the assumptions doctors base their thinking on. Sometimes these assumptions make no sense at all (as is the case with BMI) and other times you are just different enough from a "normal" person that "normal" methods simply don't apply.


  1. Romero-Corral A. et al. Accuracy of Body Mass Index in Diagnosing Obesity in the General Adult Population. International Journal of Obesity 2008. 32(6):959-966.
  2. Kennedy AP et al. Comparison of the Classification of Obesity by BMI vs. Dual Energy X-ray Absorptiometry in the Newfoundland Population. Obesity 2009. Apr 9.
  3. Chobanian AV et al. Seventh Report of the JoinT National Committee on Prevention, Detection, Evaluation, and Treatment of High Blood Pressure. Hypertension 2003. 42:1206.
  4. Hulsen HT et al. Spurious systolic hypertension in young adults; prevalence of high brachial systolic blood pressure and low central pressure and its determinants. Journal of Hypertension 2006. 24(6):1027-1032.
  5. Krzesinski JM and Saint-Remy A. Spurious systolic hypertension in youth: what does it really mean in clinical practice? Journal of Hypertension 2006. 24(6):999-1001.

By Nikhil Rao

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