Long on Meds Blog
Why Do Our Muscles Lose Power as We Age?
A new study from the University of Copenhagen helps explain one of the puzzles of aging muscle. As we get older, the tiny energy producing structures inside muscle cells become less efficient. The study points to a specific change inside those structures that may help explain why muscle loses power with age.
Why do muscles become weaker as we age?
Muscle aging is not simply a matter of muscles getting smaller. The mitochondria inside muscle cells also become less efficient. Mitochondria are the structures that help turn food into usable energy.
The Copenhagen researchers focused on cardiolipin, a special fat that helps mitochondria maintain their structure and work normally. They found that cardiolipin levels fall in aging muscle in both mice and people.
When the researchers lowered cardiolipin in young mice, their muscles began to develop changes that looked much more like old muscle.
Why does aging muscle trade power for endurance?
This was one of the most interesting parts of the study.
As cardiolipin fell and the mitochondria became stressed, the muscles shifted away from fast twitch fibers, which provide speed and power, and toward slow twitch fibers, which are built more for endurance.
In simple terms, aging muscle may be trading power for protection.
The researchers found that stressed mitochondria produced more reactive oxygen species, sometimes called free radicals. Those molecules can damage cells, but they also act as signals that cause muscle to adapt.
That helps explain why the change may be partly protective rather than simply a sign that the muscle is failing.
Can this process be reversed?
In mice, at least partly.
When the researchers restored cardiolipin to about two thirds of normal levels, muscle wasting began to reverse. In their experimental model, restoring cardiolipin also prevented the early deaths caused by severe cardiolipin loss.
That does not mean we currently have a treatment that restores aging human muscle. The study was mainly an animal experiment, and the human samples were used to confirm that cardiolipin also declines with age.
But it is encouraging because it suggests that at least some changes in aging muscle may be biologically modifiable rather than simply unavoidable.
Could medications help protect aging muscle?
Possibly, although this has not been proven.
The new study itself points toward future drugs that could act directly on cardiolipin or on a molecular switch called ERRĪ³. Those approaches are still being studied.
There is also another possible connection. Mitochondrial stress and excess free radical production can feed inflammatory pathways, including the inflammasome, one of the inflammatory pathways followed by Long on Meds. Chronic inflammation can in turn place additional stress on mitochondria.
Several medications already discussed in Long on Meds can reduce inflammation, oxidative stress, or inflammasome activity in different ways.
Colchicine, an old medication used for gout and now also used to reduce cardiovascular events, can suppress activity in the NLRP3 inflammasome pathway.
Allopurinol, commonly used to lower uric acid and prevent gout, can reduce xanthine oxidase activity and oxidative stress that can feed inflammatory signaling.
Rosuvastatin, widely used to lower cholesterol and reduce cardiovascular risk, also has anti inflammatory effects and has been shown in experimental work to influence inflammasome signaling.
Metformin, one of the most commonly used medications for type 2 diabetes, can reduce metabolic stress and has also been linked experimentally to lower NLRP3 inflammasome activity.
Other medications in the Long on Meds universe, including losartan for blood pressure, SGLT2 inhibitors for diabetes, heart and kidney protection, and GLP-1 based drugs such as semaglutide and tirzepatide for diabetes and obesity, may also reduce metabolic or inflammatory stress that can affect mitochondria.
None of these medications has been shown to prevent the cardiolipin loss described in this new study, and none has been proven to stop ordinary age related muscle loss through this pathway.
But by reducing excess inflammation, oxidative stress, and metabolic strain, some of these medications may help protect mitochondria from part of the deterioration associated with aging muscle.
That is why this study caught my attention. It adds another piece to the Long on Meds idea that the biology of aging is not one pathway and one drug. Protecting muscle may ultimately involve exercise, adequate protein, good metabolic health, and medications that reduce several different sources of damage at the same time.
Learn more about inflammaging and inflammatory pathways, or use Check a Medication to examine these medications and other therapies.