Don’t believe the hype – How much muscle do you need for longevity.

You may have noticed the pendulum swinging with the new craze of huge protein consumption rates and big push to gain muscle mass. I came across one woman’s channel trying to convince every woman to bulk up – to go hard against the fear of it. Indeed I have had many women approach me over the past 2 decades for training and say that they don’t want to bulk up. And then you have loads of trainers, including myself that have for years tried to explain how hard it is to truly get bulky. But being aware that it’s difficult doesn’t mean you should or shouldn’t do it. It is not, though it would appear many would disagree with me, all good to get huge. There are consequences, amenorrhea being just one of them. But to get attention now, you have to sell the other end of the spectrum, now, instead of simply reassuring that bulkiness is not necessary and also very unlikely without massive changes and effort, we try and sell the bulk, be the bulk, Bulk Smash. Extremes sell but guess what, as always, the answer to most questions lies in the middle, close to our instincts and often less fun to talk about at a party.

PS – if you see me at a party please don’t talk to me about your training protocol or diet. Yikes.

I am going to focus on one study for this short article. the results of which I have seen be been blown out of proportion on the ol’ “socials.” The study is titled Muscle Mass Index as a Predictor of Longevity in Older-Adults. You can read it in its entirety here. To be clear, it is a great study but it only has one real conclusion and it is not what you think it is. No one should change their habits based off of one study, this should be a golden rule in moving forward through the wellness influencer chaos. We want multiple studies attempting to recreate the results of the first study and more studies looking at various factors that have been outlined as possible mechanisms of causation, etc. Well intentioned media outlets or individuals may take too much away from a conclusion in a study. I have done this very thing. But let’s take a look at this one study and see what we can make of it. I will also tag a few other studies later on so you can see what has been done in this area of interest but this study in particular as well as a few others have been misinterpreted and oversimplified with regards to muscle mass and longevity.

The results as listed in the basic summary say that total mortality was significantly lower in the group with the most muscle mass compared to the group with the least. It goes on to say that muscle mass may be an important indicator of mortality rate compared to total body mass. This is an important point. If you simply look at the results and say that people with more muscle live longer, this would be both true and yet incomplete and non conclusive. You need to read the entire study in order to get the real takeaway with all the nuance and warnings.

There were 4 cohorts in the study, each with increasing levels of muscle mass – cohort 1 having the least and cohort 4 having the most. Risk of mortality was significantly lower for cohorts 3 and 4 compared to cohort 1. But the difference from the 3rd and 4th group was not significant.

* NOTE – This may suggest a point of diminishing returns, Sometimes when you reach or pass a point of diminishing returns you start to witness detrimental effects via other biological mechanisms. This is the principal of toxicity for every single compound we can consume. I can’t imagine a logical explanation that consuming vast amounts of protein, for example, would be any different. Though it might be safe at quite high levels, it does not mean that more is always better. There probably becomes a point when the body will either not use it and remove it or begin a potentially problematic build up through an unspecified mechanism.

I am unsure as to what the muscle mass quartiles look like in relative terms. I will try and do the calculations and edit this article shortly so that we can see what someone in the 75th percentile looks like within the age brackets studied. There is most definitely a wide variance within the cohort, this group is not simply made up of body builders.

The demographic the used were men over 55 and women over 65 who were not underweight or undernourished. They compared results among sexes, muscle mass index and non muscle mass index as well as body mass index as predictors of mortality and all cause mortality. The adjustments made for confounding variables were decent and they made the necessary calculations to make up for any lost data.

In studies of this nature, method to measure muscle mass is very important The 4 best ways are imaging based, including the gold standard of magnetic resonance imaging (MRI), bioelectric impedance (BI), dual x-ray absorptiometry (DXA) and computed tomography (CT). These are all cost prohibitive for many studies and so an equation is often used. This study did us BI and then put it into an equation. This method is said to be more precise for younger cohorts and maybe problematic with older people. So while we need to recognize this as a potential issue the authors break their reasoning down in using this method and seem to make it more plausible.

The study did convincingly show that muscle mass is a significant predictor outside of traditional cardiovascular risk factors such as hypertension and inflammation as well metabolic risk factors such as diabetes and insulin resistance. It also presented the idea that a protein reserve could be a causal pathway towards longevity as it can protect against long term illness. Indeed we have a growing understanding of muscle as part of our endocrine system, a metabolic driver as well as part of our immune function. Intuitively, these insights bring us closer to a holistic view of our health and yet we hear influencers treating the research as if muscle mass is the most important thing.

The full summary clearly states that genetic predisposition and consistent exercise may bring about greater cardiovascular fitness which then increases survival rates through non identified cardiovascular factors (like decreased blood flow to muscle). If these cardiovascular fitness factors allow for muscle maintenance then muscle mass could be a representation of this protective factor more than a singular driver of protection. Think of it like witnessing a glider in the sky – from a far enough distance it looks like a regular plane flying by the power of its engines, yet in truth it is the wind, air pressure and vehicle design that is carrying it through. Just because it looks like one thing doesn’t mean it is the whole story.

The authors of this study explicitly say that no conclusion of causation can be made. This might sound like nitpicking but this is just good science – being weary of grand conclusions, differentiating between correlation and causation and hypothesizing mechanisms for later research. It would be great if we saw more of this from the health gurus on Instagram and Youtube. Another limitation which they lay out themselves is that most people with high muscle mass also have low or lower body fat which may be inherently more protective against all cause mortality than the muscle mass itself. This is important. This kind of nuance can change interpretation of the results into more specific actionable goals.

The coolest thing we get from this study is that it made it clear that muscle mass in relation to body height (as used in their equation) is a notable predictor of mortality and that total body mass as used in the body mass index (BMI) is less reliable as such.

Again, no one should make serious changes to lifestyle based off of one study. But when you begin to zoom out and seek the big picture the changes you seek may be more reasonable. When you do this you might for example, bring the ceiling down on maximum muscle gains and focus on fat loss. Or you may begin to ask what foods are actually necessary and in which quantities. So let’s all hesitate a bit longer before saying we should all bulk up and eat huge quantities of protein that may include massive saturated fat loads. Is that good for you as an individual? Based off of what data? Get some tests done and see where you stand.

I try not to throw the baby out with the bathwater. I recognize that social media influencers can make great contributions to health awareness as well as guide people towards positive actionable changes. But the wellness industry is now valued higher than the pharmaceutical industry. The money is spread out towards many more characters but the potential for personal gain is so high and with zero regulation. So we need to take Andrew Huberman, Gabrielle Lyon, Casey Means, Mark Hyman, Ben Greenfield and the rest of the mega influencers with a grain of salt. The single most important thing they all contribute to the population at large is that they are placing means of control into our hands. They show that you too can look for the evidence and tools that can optimize your health while the medical institutions are difficult to navigate. But we can not blindly trust any one person, we all make mistakes. I make them all the time so don’t blindly trust me either! Here are some red flags for health information sources

Vilifying specific food sources
Touting fix-all food sources or methods (aka cold plunges, carnivore diets, broccoli, etc.)
Fixating on a specific biological mechanism rather than including large study general health outcomes
Blindly refuting all scientific endevaours from one insitution
Assuming that individual wellness personalities have peoples’ best interest at heart
Making grand claims from a singular study
Making conclusions on human health from in-vitro or animal studies

As promised here is a list of other studies that add to the story of muscle mass and longevity. They are all worth reading, even if it is just the conclusions….though don’t make that a habit!

This is nowhere near a complete list. But it does show that there is a growing body of evidence suggesting the importance of muscle mass for both health-span and lifespan and that it is quite varied in how it works and may be prudent to not assume bigger is always better.

I will continue this theme of the value of muscle mass with my next article explaining my opinion on functionality vs the cost of redundancy – where functionality is multi pronged.

Don’t believe the hype – How much muscle do you need for longevity.

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