Here is the full transcript of Dr Brendan Egan’s talk titled “Muscle Matters” at TEDxUCD conference.
In this talk, Dr. Brendan Egan emphasizes the critical importance of maintaining muscle mass, particularly as we age. He points out that individuals can lose significant muscle mass rapidly during periods of inactivity, such as bed rest. Egan argues that conventional advice of regular walking is insufficient for muscle maintenance, advocating instead for strength training and bodyweight exercises.
He cites research showing that even elderly individuals can significantly improve muscle mass and strength through targeted exercise. Egan introduces the concept of progressive overload in training, using the example of Milo and the bull to illustrate how gradually increasing demands lead to strength gains. He also highlights the success of bodyweight exercises in both young and older adults, demonstrating improvements in muscle mass and overall health.
Ultimately, Egan stresses the need for personalized exercise regimens, akin to medical prescriptions, to effectively combat age-related muscle wasting and promote longevity.
Listen to the audio version here:
TRANSCRIPT:
Energy Expenditure and Muscle Function
As you sit there in your chair, you’re expending a rough amount of energy, somewhere around a calorie per minute. When we exercise, we can increase this by about 20 or 30-fold. As you sit there, your muscle contributes about 30% of your energy. During exercise, it contributes about 90% of your energy. So, it becomes the major site of where we burn carbohydrate and fat.
And when we eat a meal, about 80% of the energy that’s ingested in that meal is distributed to the muscle. In other words, when muscle begins to fail, or when we develop problems with our muscle, it’s not surprising then that we develop a range of diseases associated with that.
The two things that have happened in modern science that have unintended consequences in terms of the way that muscle functions are automation and medication. So, in modern life now, we’re predisposed to being physically inactive. We spend a large amount of our time in a sitting position. Even if we do a half hour of purposeful exercise first thing in the morning, we spend about 90% of the next 15 and a half hours of waking in a seated position.
Consequences of Modern Lifestyle
So, one of the problems with sitting is that it’s an independent risk factor for a majority of diseases. In other words, even if you do exercise first thing in the morning, or last thing at night, or whenever you exercise during the day, if you do it in a single bout, and you spend the rest of your day sitting, you might be classified as an ‘active couch potato.’ So, potatoes don’t have much use for muscles.
If you look at someone like this, and we tend to associate inactivity and inappropriate diets with an increase in size, in actual fact, the muscles of individuals such as this are actually getting smaller and smaller, and working less and less.
The second major thing that modern science has delivered us is medication. As a result, we’re living longer and longer. So, we have a worldwide aging or graying population. If you look at the yellow segment on those pie charts, that represents the numbers of people who are over 65. Our current projections, sometime after the year 2050, suggest that the numbers of people greater than 65 years of age will exceed the numbers of people less than 15 years of age for the first time in human history.
Aging and Health Challenges
However, with aging and extended lifespans, due to this improvement in our medication, unfortunately, that’s associated with chronic diseases. In data from the US, adults aged over 65 years, the current numbers would suggest that 92.2% of those individuals have one or more chronic diseases. So, although we’re living longer, we might not necessarily be living healthier. In this case, chronic diseases were defined as the usual ones we tend to hear about, like hypertension, coronary heart disease, stroke, cancer, and so forth.
But there’s one disease that’s not mentioned here that I want to talk a bit more about today, and that’s sarcopenia. Sarcopenia is defined as the age-related wasting of muscle. The word comes from Greek, which means the poverty of flesh. But it also means the poverty of strength. So, we lose muscle mass, and we lose strength as we age. And there’s no way it’s inescapable. It’s a fact that happens.
After about the age of 30, we lose 3 to 8% of our muscle every decade. Keep that number in mind, because I’m going to come back to it. Every decade, we lose somewhere between 3 and 8% of our muscle. On the right-hand side, in the second figure there, you see the appearance of the thigh muscle of an individual, a cross-section of their thigh. What you can see there is that an elderly individual, they’ve lost a large proportion of their muscle mass. The white color there indicates adipose tissue or fat. So, muscle has shrunk. We’ve lost muscle as we age.
Sarcopenia and Its Impact
Beneath that is a 74-year-old athlete who has trained their whole life and has managed to maintain their muscle mass, despite what I said was the inescapable fact that we would lose muscle throughout our life.
So, you might wonder, what is the prevalence of sarcopenia? Is it just some disease that this guy’s really interested in and it’s not really that relevant? Well, at the moment, in over 65s, this is data from the US, it’s about 20% prevalence. In people over the age of 85, greater than half of the individuals have sarcopenia.
Now, when you lose strength and you lose power in your muscles, these are things that are greatly associated with balance. If you lose your capacity to balance, you’re more predisposed to falls and fractures. So, this loss of muscle mass is a strong risk factor for frailty syndromes, for loss of independence, and for general ill health as we age.
We don’t have any figures for Ireland, but what we do know in Ireland is that there’s another part to this story which is disease-related malnutrition.
Disease-Related Malnutrition
This might surprise you, but in Ireland, at any one time, there’s 140,000 people who are suffering from disease-related malnutrition. That costs about, in direct cost, about 1.5 billion euro to the exchequer. And you might think, well, how much does that mean? What kind of disease is this again? That’s more than the direct cost of obesity. So, this is an invisible type of disease, disease-related malnutrition very strongly associated with age-related muscle wasting.
So, why is strength important? I mentioned the incidence of frailty and loss of independence. If we look at individuals who are either over 60 or under 60 and we look at their strength, so their whole body strength, three colors here represent weak individuals, average individuals, and strong individuals.
If you look at the two red bars, what you see there is that as we age, so the over 60s, they have a four times elevated death rate compared to the under 60s. So, that makes sense. If we’re a little older, we’re more likely to die.
However, on the right-hand side, if you compare the green to the red, the strongest third of the population have half the death rate of those who are weakest. In other words, if you preserve your muscle mass, you have a greater chance of living that little bit longer.
Now, why would that effect be so obvious? And why would it be of relevance to something like cancer? Are there other diseases that sarcopenia or muscle wasting relate to? And there are. So, all of these diseases listed on this slide coincide with muscle wasting.
Muscle Wasting and Disease
In each one of those, when the disease manifests itself, it’s also associated with a loss of muscle mass and therefore a loss of independence. The one I want to focus on is immobilization and bed rest. So, if you take young healthy males in their 20s, student age, student population, and you’ve probably heard of this 10,000 steps that you need to do on any given day in order to be healthy.
If you take people who are making those 10,000 steps and you reduce their activity by making them take elevators, making them take escalators, pushing them around in wheelchairs, making them sit a lot more, you reduce their number of steps to 2,000.
Muscle Mass Loss and Its Implications
They lose about 5% of their muscle mass in the space of 14 days. So, I said that usually we lose about 3% to 8% per decade over the age of 30. These guys lose 5% of their muscle mass within 14 days. If an elderly person over the age of 70 is bedridden for 10 days, they lose 10% of their muscle mass. In other words, depending on the situation, in as little as two weeks, you can lose the equivalent muscle mass of what would take a decade to lose. So, we want to avoid these things. We want to avoid mobilization. We want to stay active.
We want to avoid bed rest where possible. So, how should we do this? Typically, what we’re told is that we need to get out and walk more. We need to do half an hour of activity, accumulating on five different days of the week.
Well, I’m going to tell you that that’s probably not enough. So, the principles of specificity in terms of exercise training is that the body adapts specifically to the imposed demands. So, if we want to get bigger, if we want to improve our strength and improve our muscles, we have to lift weight. Going out for a walk isn’t going to make you stronger.
Exercise and Muscle Strength
In fact, there’s some evidence to say that people who are lifelong endurance or aerobic or cardio exercisers are predisposed to losing muscle mass compared to those individuals who do strength training. The other interesting thing is that when it comes to diseases like diabetes and obesity, the most recent evidence would suggest that it’s combined endurance and aerobic exercise that works. You shouldn’t just be doing one or the other. There should be a combination within there. A second principle in exercise training is the principle of progressive overload.
This is Milo, the wrestler, 2,500 years ago, a famous Greek wrestler. The story goes that in order to develop his strength as he grew, he used to carry a bull, a calf, around from a young age. So, he carried it every day, and as the bull got bigger, he got stronger. I don’t know if this is true, but the point is that each day he pushed himself a little bit harder and his body adapted accordingly. That’s an important principle of the way we exercise.
Exercise in the Elderly
So, then the question is, if an adult is old, or in this case, they’re over 85 years of age, if we exercise training, can they actually make improvements? So, on the left-hand side, what you’re seeing there is pre and post, and what you’re looking at is the cross-sectional area. In this particular individual, that person’s muscle in their quad, again, in their thigh muscle, has increased by about 44%. On the right-hand side, you’re looking at their improvement in strength. It’s improved by about 50%. That was after 12 weeks of training that focused on the quadricep muscles in 85-year-old individuals.
So, in this case, the muscle wasting could be reversed. In other words, we’ve reversed the aging process. So, how should we exercise then? Do we have to go to a gym? Do we have to invest in expensive equipment? Something we’re excited about at UCD at the moment is using bodyweight exercises. These are exercises that you use your own bodyweight in space to provide a resistance against your muscles. So, I’ll give you two little studies that we’ve done right now.
Bodyweight Exercises and Their Benefits
We took young college-age males, again, obese and overweight, and we trained them for six weeks, three days a week, half an hour each day, and all they did were these bodyweight-type exercises, no equipment. After the six weeks, we saw about a 3% improvement in muscle mass, particularly in the legs, and we had that holy grail. They lost a small bit of fat as well. They were young individuals. In older adults, starting at the age of 55, but of a mean age of about 63, we see the same thing after 12 weeks. Bodyweight only exercises three times a week. We see about a 3% improvement in their muscle mass.
Improving muscle mass is one thing, but these exercises are very similar to things we do in everyday activities. We lift things above our head, we get up off the ground, we get up out of chairs. These are what we call activities of daily living. One of the major predictors of loss of independence is when an older adult can no longer do these activities of daily living. We’re excited now to begin to look at these bodyweight exercises and how they might improve the overall health and functional capacity of older adults.
The Continuum of Muscle Wasting and Exercise Prescription
I suppose the last thing I’ll say is that in the case of sarcopenia or muscle wasting, you don’t just wake up one day and have this situation. It’s a continuum. It progresses over time. I was talking about those bodyweight exercises being able to increase muscle mass, but if we can just delay the aging process, so if we just maintain muscle mass rather than actually having to improve it, that in itself will have benefits to their overall health.
My simple message is this: We need to prescribe exercise like we prescribe medicine. We shouldn’t just give everyone the same medicine. We should treat the individual and we should treat the condition. Going out and doing 30 minutes of walking every day might not cut it when it comes to people who have age-related muscle wasting. In other words, what I’d say is use it or lose it because muscle matters and only the strong survive.