The importance of muscle for health, happiness and longevity
The importance of muscle for health and longevity is rarely appreciated. I have written before about how to preserve muscle mass in order to age gracefully, but here I go into more detail on why it is important. It can literally be a matter of life or death.
I am going to simplify and summarise this paper – the underappreciated role of muscle in health and disease – and then add my own thoughts on the importance of muscle.
1. Protein is essential for the maintenance of life
The vital organs – brain, liver, heart, skin, lungs and so on – have a constant need for protein. They have a constant cell turnover, replacing old with new and requiring a continuous supply of amino acids to build new proteins. Without that, these organs would degenerate and become dysfunctional. If continued, the result would be, ultimately, death.
Amino acids are supplied either by consuming protein or, in the absence of food, by the skeletal muscles. Muscle tissue is the body’s primary store of protein and the source of amino acids in a fasted state.
Amino acids also allow the liver to create new glucose molecules, helping to maintain constant blood sugar levels.
So effective is the role of skeletal muscle in providing amino acids that the protein content of the vital organs and blood glucose concentrations can remain constant for a long time in the absence of dietary intake, providing sufficient muscle is present to provide the amino acids.
In contrast, when muscle is severely depleted, there may not be a sufficient pool of amino acids to aid recovery or even sustain life. Depletion of muscle mass has been identified as the cause of death in human starvation.
2. Protein demand is increased during physical stress
There is an increased demand for amino acids when the body has been injured or suffered some other physical trauma, or when it is battling a critical illness such as cancer or sepsis. It has been reported that the need for amino acids and therefore protein is increased four-fold in burns victims. For example, an 80kg person suffering serious burns might require an intake of around 320g protein per day.
Any wound or serious illness is going to increase demand for amino acids. If this is accompanied by a loss of appetite then the recovery process is going to draw heavily on the stores of protein available in the muscles. So it is beneficial to maintain as much muscle as possible to cater for any such eventuality. A lack of muscle has been shown to be detrimental to the survival rates of cancer and burns victims. Cancer survival and recurrence is worse in those with less muscle.
The strength and function associated with increased muscle is important for the recovery process. Physical impairment or loss of function can lengthen the recovery. If muscle is deficient before the trauma then the resulting loss of muscle and function may mean that the victim never recovers. For example, a lack of muscle is one reason why 50% of women over the age of 65 who break a hip never walk again.
This section is particularly pertinent to recent events in my life. My father passed away a few weeks ago following a short illness. Over a number of years he had become increasingly inactive due to arthritic knees and then a leaky valve which made him breathless. He lost a great deal of muscle and became frail and stooped. He had a prolonged period of inactivity after he had his valve replaced and then another period of bed rest following the removal of a thrombosis which was a complication of the heart operation. The associated loss of more muscle left him so frail he could barely walk or keep his head up. He had literally wasted away. When he had a minor stroke a couple of months later, he had no reserves of protein to maintain his organs or to keep his immune system in good order to fight infection.
3. Muscle mass helps recovery from chronic diseases
Heart failure and cancer are often associated with a rapid and extensive loss of muscle and strength. The amount of muscle prior to illness is an important determinant of survival.
Sarcopenia – the loss of muscle with ageing – can have a huge effect on quality of life and ultimately of survival. Sarcopenia is by far the biggest factor in the development of frailty, the likelihood of falls and the loss of activity for every day living. Ultimately this can lead to being institutionalised.
4. Muscle fights obesity
You will find a lot written about the importance of muscle for keeping the metabolism high. Whilst it is true that protein turnover and muscle tonicity have an energy demand, it’s not as high as some of the figures you might find.
Nevertheless, it’s a very real and significant effect. It is estimated that an extra 10kg of muscle can burn extra energy equivalent to 4.7kg (10.4lbs) of fat per year. Over the course of a number of years – the typical timespan associated with becoming obese – this can add up to several stones.
In studies an increase in lean mass has been associated with a decrease in fat mass. When dieting, it is important to get sufficient protein to maintain muscle.
5. The importance of muscle in preventing insulin resistance and diabetes
It is becoming clearer that changes in the metabolic function of muscle is a major contributor to the development of insulin resistance and, ultimately, diabetes.
What does that mean? Mainly it means that a loss in the ability of muscle to burn fat as a fuel is at the heart of impaired insulin sensitivity. A lack of physical activity decreases the ability of muscle to burn fat. So essentially, a lack of exercise is a major cause of insulin resistance. Exercise can reverse insulin sensitivity by restoring the ability of muscle to burn fat.
Early morning fasted cardio is a great way to maximise the ability of muscle to burn fat. We have written about the benefits of steady cardio in a previous article. Here we are talking mainly about maintaining the metabolic function of muscle rather than muscle mass. That said, providing the ability of muscle to burn fat is maintained, the more muscle one has, the better the body’s overall ability to burn fat.
6. Muscle mass helps prevent osteoporosis
Mechanical force on bone is essential for bone strength and mass. Although weight bearing is an important source of mechanical force, the largest direct mechanical force comes from muscle contractions. Studies on both athletes and stroke victims support this. Bone mass and muscle strength are positively correlated, so the importance of muscle is clear in preventing osteoporosis.
Those with the least amount of muscle are at increased risk of falls due to a lack of strength and impaired balance. Those who do fall are more likely to break bones if they have poor bone density due to a lack of muscle.
The maintenance of bone with ageing is highly dependent on the maintenance of muscle.
7. The importance of muscle for good posture
Ageing leads to a loss of quality in muscle. That means muscles become riddled with adhesions, become less pliable, begin to accumulate connective fibres such as collagen and can become irreversibly shortened. A lifetime of sitting can lead to tight hips and a tight chest with resulting pelvic tilt, lower back pain, rounded shoulders, shoulder pain and stooped appearance. Surgery may even be necessary to alleviate some of the complications. Poor posture is both a cause and a consequence of movement dysfunction. The knock-on effects include joint pain, injury and breathing difficulties, as well as a deterioration in one’s appearance and confidence.
Maintaining muscle and strength, particularly in the key postural muscles, can help to counteract or prevent a deterioration in posture. Regular maintenance work such as foam rolling and massage can maintain the quality of muscle whilst activities such as strength training and yoga can help maintain the strength, mass and flexibility.
8. Muscle maintains strength and functional ability
With more muscle and more strength comes improved capability. Activities such as working in the garden, going for long walks, climbing hills, cycling and so on can be maintained well into old age simply by maintaining strength and function.
Being strong also makes every day living seem like less effort, so there is an inclination to move more and less likelihood of putting on weight.
9. Muscle helps improve confidence
Having improved capability and improved posture is often associated with improved confidence. That covers confidence in certain movements such as climbing stairs or stepping over obstacles, as well as confidence in one’s appearance, either due to better body composition, improved shape or improved posture.
10. Muscle makes you more attractive!
Possibly controversial, but it is undeniably the case that improved muscle tone can be attractive to potential partners. It is evident in the animal kingdom, with the stronger animals becoming the dominant pack or herd leaders and being more likely to mate. That the stronger individuals are more attractive to mates makes sense from an evolutionary standpoint, as stronger individuals are more likely to prevail and therefore more likely to facilitate the survival of the species. Combining your own genes with the genes of the stronger individuals gives your own genes a better chance of propagating down the line. Like it or not, the same primal predisposition to find stronger individuals attractive is programmed into the human animal.
I’m sure you’ll agree that the above list of opinions, facts and citations is compelling evidence of the importance of muscle. It’s never too late to change your eating and exercise habits for the better. Follow the advice in our earlier article to start putting on some muscle and get ready to enjoy a long and active life.