Longevity enthusiasts either fear death or love existence. Why else would you want to live forever? It is also apparent that they crave quality of life, not just quantity. As such, most of them are actively avoiding death through lifestyle and medical interventions.
Keeping it simple
Life is complex, and while getting bogged down in the details is essential, it’s even more important to be proactive. And while debates around the most revealing metrics for longevity abound, the scientific literature gives a simple answer.
Muscle mass index is the most important indicator of longevity in older adults. Yes, you heard that right. Muscle mass is the single most important metric for predicting lifespan. As a minimalist, I like the simplicity of that answer, but, at the same time, I want to test the theory to see what else I can learn.
Should we be concerned?
One concern is that we often hear about the dangers of high protein diets or the negative impact of IGF & m-Tor activation on longevity. Yet, high levels of skeletal muscle are only possible through high protein diets and m-Tor activation (m-Tor is the regulating pathway through which muscle growth and muscle atrophy are regulated).
Drs Shaun Baker and Paul Saladinho have some controversial views on the subject that are well worth exploring. Suffice to say that the data against high protein diets and avoiding m-Tor activation may not be as conclusive as many popular media outlets would lead one to believe.
Muscle volume vs Muscle quality
Before moving on, it’s worth mentioning the distinction Dr Peter Attia makes when explaining the correlation between longevity and muscle mass. He posits that it is actual strength that indicates the potential for healthy ageing, but that muscle mass is correlated to physical strength, so it’s almost the same thing. The quality of muscle and neurological connection to the muscle is important, it’s not just about size or volume.
BMI vs Muscle mass
Scientific American, a respected science magazine, reported in 2014 that doctors have become aware that body mass Index is a less reliable predictor of longevity than muscle mass.
Dr Gabrielle Lyon has famously stated that the crisis amongst the population today is not so much that we are over-fat, but that we are under-muscled. Dr Lyon claims that muscle is the organ of longevity.
Muscle is not only responsible for clearing glucose from our blood, but also releases chemical signals called myokines which have a host of health benefits for keeping inflammation low and signaling other pathways that improve overall healthspan.
What benefits do muscles have for older individuals?
One could name many benefits, but in the interest of keeping this article short, I will only describe two. These are decreased risks for cognitive decline and hospitalisation.
1. Age-related cognitive decline
One important correlation between muscle and longevity is that higher levels of BDNF or brain-derived neurotrophic factor reduces the risk of cognitive decline. This molecule is associated with brain and neurological health. BDNF gets produced in skeletal muscle, and there is a strong correlation between exercise and blood-serum levels of BDNF.
There is clear evidence that BDNF protects against Alzheimer’s Disease and other forms of age-related dementia. Maintaining healthy skeletal muscle through diet and exercise is one of the most powerful weapons against cognitive decline.
2. Sarcopenia and hospitalisation
Sarcopenia is age-related muscle loss. We all know that older individuals have lower levels of skeletal muscle and that muscle loss occurs as we age. Studies have shown that in any given age demographic, individuals with more muscle have lower all-cause mortality. There is a significant correlation between sarcopenia and hospitalisation. The amount of muscle you have when an adverse health event occurs correlates to the chances of a speedy and full recovery.
Studies have also shown a strong correlation between sarcopenia and mortality, particularly in older individuals of a similar age. Good musculature at any age is a reliable predictor of health outcomes, but this becomes more statistically significant in older individuals. We will all lose muscle as we age, but those who approach old age with higher amounts of muscle will enjoy a longer healthspan.
Maintaining or increasing muscle mass
There is an old maxim, “you can’t manage what you can’t measure”. Measuring strength and cardiovascular fitness is quite easy, but for those who are sedentary and don’t exercise, knowing their status is quite tricky.
This brings us to the question of how to measure muscle mass. A paper published in 2011 suggested that DXA-Scans, commonly called dexa scans, can be performed in combination with MRI and CT scans.
There is no ideal index as yet stating what percentage of skeletal muscle is ideal for a given individual, but suffice to say, low musculature will reveal itself during scans or fitness evaluations.
The next thing you may be wondering about is whether you can build muscle when you are already old. The answer is definitely yes, but at a lower rate than you could when you were in your twenties. There are also a few other hacks that will help you preserve muscle as you age.
These hacks include:
1. Sleep and muscle mass
As if we didn’t already have overwhelming evidence supporting the importance of good quality sleep, along comes another study to drive home the importance of getting between 7 and 8 hours of sleep.
Poor sleep quality is associated with reduced strength and lower levels of skeletal muscle. Sleeping between 7 and 8 hours per night is universally associated with better ageing and better cognitive and physical performance throughout your life, particularly in old age. Olympic athletes, chess masters, artists and most other high-performing individuals attest to this.
2. Diet and muscle mass
Protein is the cornerstone of maintaining healthy muscle as you age. Recommendations for the amount of protein you should consume vary and there is a lot of contradictory advice. I am hesitant to wander into the weeds on this topic, but I will say that universally animal protein has a higher and better quality amino acid profile. Leucine, one of the essential amino acids, is associated with activating m-Tor and building muscle. Leucine should be ingested on a per-dose basis of at least 2,5 grams per meal, once per day. Its efficacy and safety in the elderly has been demonstrated and you can view the paper here. 200 grams of red meat should put you above that threshold, or at least 5 eggs in one sitting. You will also need to ensure that your overall protein intake for the day is around 0,5 to 1 gram of protein per kilogram of ideal body mass. If you are exercising, you will need to consume more.
3. Exercise and muscle mass
You will need to get a professional evaluation before starting an exercise regimen. Weights, cardio and other systems like primal movements will contribute to maintaining muscle mass, increasing VO2 max and maintaining the mind-muscle connection. Dr Peter Attia is a well-known expert in this field and a summary of his advice on strength training regimens as well as targeted cardio training for longevity can be viewed at the following link.
Weight training for maintaining muscle mass is effective when you train every muscle group at least once a week, performing 3 sets of 10 reps at around 30% of your one rep maximum. To build new muscle, you should increase the weight to around 60% of your one rep maximum weight. For VO2 max, you need to spend at least 10 minutes per week performing close to your maximum cardiovascular output, meaning that you should run as fast as you can. You can also do this on a bicycle, in the pool, or however you can get your heart rate elevated. You can do this in two sessions, let say a Monday and Thursday, in five one-minute intervals. Primal movements will improve mobility, range of motion, balance and the neurological connection between muscles and the brain. These can be taxing and should only be done in consultation with a certified fitness coach.
Healthy aging and muscle mass
The evidence establishing the link between muscle mass and healthy ageing is not just overwhelming but also utterly convincing. This article should be viewed as a primer to get you into the body of knowledge and expertise that covers the various topics.
In summary, a little time spent taking care of your health now will have large payoffs in the future and add several quality years to your lifespan.