Sarcopenia, the Progressive Loss of Muscle Mass Due to Aging, is Preventable and Reversible!
So why is it so hard to keep muscle mass when we age? Turns out it is caused by sarcopenia. Really! I'm not making up the term. Sarcopenia is the progressive loss of muscle mass that results from the normal aging process. It has been felt, in the past, that the loss of one to two percent of your muscle mass each year after the age of 40 is inevitable.
Turns out there are lots of things we can do about sarcopenia. One of them is to actually build some upper body muscles! Runners tend to feel like if they bulk up at all in their upper body that it will slow them down. Research actually has refuted this claim over and over, but it is still one of those long-standing running myths. Strength training actually helps preserve muscles and strengthen bones which often improves your running economy and hence makes you more efficient, reducing the amount of energy to run at a certain pace. Win-Win!
Many factors go into the onset of sarcopenia. Chronic disease and environmental factors can accelerate loss of muscle mass, but these are not really controllable. Factors under our control that affect the progression of sarcopenia are motor unit restructuring, protein deficiency, and changes in hormone concentrations. These combine to produce the age related loss of muscle coordination and mass.
Really, it is all about proteins. There are two kinds of proteins; non-essential (those your body can synthesize) and essential proteins (proteins we need to get from foods). Your body seeks a balance between protein production (synthesis) and usage (metabolism) for energy and cell structure.
We don't usually lose our ability to metabolize proteins with age, but we do lose our ability to synthesize them. This is where hormone balance comes into play. Things like Insulin-like growth hormone (IGF-1), testosterone and growth hormone. As our bodies age, our hormone concentrations decline. This is why aging baseball players love growth hormone, they think it stops sarcopenia! (Hgh declines after age 40 but there is not good research that proves supplementation will actually help!) What's more, it appears that as we age, we actually require more protein but continue with a similar diet hence we are out of balance.
The hormone decline and protein deficiency one-two punch is largely responsible for sarcopenia, but when you add the most vital aspect - motor unit restructuring - they combine to form a cocktail that results in the physical manifestation of aging.
Motor unit restructuring is the product of the inevitable death of neuron cells. Fast twitch neurons (those responsible for precise or quick movements) die off first. When the cell reaches its predetermined life span, it dies. When a motor neuron dies, the muscle fibers that are under its command can deteriorate or atrophy. To prevent atrophy, when a fast twitch neuron dies, a slow twitch neuron nearby attaches itself to the now abandoned muscle fibers, innervating and keeping them alive. This change is known as motor unit restructuring. This is why we become slower and less coordinated as we age.
So how can we thwart this process? Move! Often! Sitting on the couch and leading a sedentary lifestyle is a good way to ensure sarcopenia with age. The best way to cure or at lest slow down the onset of muscle mass loss is resistance training. We recommend our patients participate in daily exercise, but often this is not enough. It will help your cardiovascular system, but resistance training with weights is the only way to reverse muscle mass loss. Couple this with increases protein intake to have the building blocks to redevelop muscles.
So, you want to be able to beat the young pups when you are in your 50's and 60's? Talk to your doctor about any health issues like diabetes or hypertension. Change your diet to higher protein and less carbohydrates. Forgo the pasta dinners and add lean protein! Resistance training with light weights and high repetitions at least 45 minutes, three times a week. Make it a habit you will take into your senior years! You will thank me when you are still running in your 70's!