“Do you even lift, bro?”
It’s a popular meme these days on social media. And while it may poke fun at the gym rat meatheads, whose lives revolve around banging weights and getting a pump on, there’s some deeper relevance to it that may surprise you.
Your life may not revolve around sculpting the perfect tricep horseshoe or pretending to wipe sweat off your face just so the hottie on the treadmill can see your abs in the mirror, but lifting weights and getting strong has serious implications on your life outside the gym. In fact, the top two indicators of health and longevity, for both men and women, are muscle mass and strength. Not cardio endurance. Not flexibility. Not stamina. Muscle mass and strength.
Still think you’re getting healthy by training for that marathon or Iron Man? Keep reading, my cortisol-ridden friend. You’re going to learn how vital it is to feed and grow your muscles.
The Role of Muscle Protein in Metabolism
First, a little bit about how to keep the muscle you already have.
Your body is made up of a lot of protein (among other things, obviously). Maintaining the protein content of your tissues and organs, such as the skin, brain, heart, and liver, is essential for survival. These tissues and organs rely on a steady supply of amino acids to serve as precursors for the synthesis of new proteins.
It has been recognized since the early 1960s that, in the absence of nutrient intake, muscle protein serves as the principal reservoir to replace blood amino acid taken up by other tissues (1). This means that if you don’t supply your body with dietary protein, it’s going to steal protein from your own muscle to keep yourself alive.
Ok, so what? You still may think, “I just want to look small and thin. If that costs me some muscle, I’m cool with it.” Good point, case closed.
Oh wait, I forgot. You’re wrong.
Muscle and Critical Illness
If supporting daily life wasn’t enough, the stressed state (such as disease, injury, or hard training) imposes even greater demands for amino acids from muscle protein. They’re necessary for functions like supporting the liver, the immune system, and wound healing. If you do not supply yourself with enough amino acids, you will continue to break down your body’s own muscle to aid recovery.
On top of that, if you have a preexisting deficiency of muscle mass before trauma, the atrophy during hospitalization may prevent full recovery from ever happening. For this reason, over 50% of women older than 65 who break a hip in a fall never walk again (2). It’s also been shown that survival from severe burn injury is lowest in individuals with reduced lean body mass (3).
Heart disease and cancer are two major chronic diseases suffered in the United States. Both cardiac failure and cancer often result in rapid and extensive loss of muscle mass, strength, and metabolic function. So if you’re going in to a battle with cancer, and you’re already lacking sufficient muscle mass, how do you think you’re going to fare against that disease?
So far, these seem like pretty valid reasons to eat enough protein to maintain muscle. Let’s keep digging.
Muscle in Insulin Resistance and Diabetes
Type 2 diabetes develops in stages. It starts with a decreased ability of insulin to stimulate muscle to clear sugar from the blood. You then over-produce insulin to try to catch up. Eventually, the pancreas loses the ability to secrete extra insulin and you’re left with a whole bunch of sugar in your bloodstream. Aka – not good.
What starts this whole situation in the first place? Obviously, nutrition is a key factor. But looking closer, alterations in the metabolic function of muscle are central to the development of insulin resistance and ultimately diabetes (4). In other words, if your muscles aren’t functioning correctly at the cellular level, you’re screwed.
The capacity to oxidize (burn up) fats in the body is reduced in insulin-resistant people. This deficiency is due to a decline in mitochondrial function (the powerhouse of your cells). There are many potential causes of decreased mitochondrial capacity, including genetics, but a lack of physical activity is most likely a major factor in patients with type 2 diabetes. Mitochondrial capacity is decreased by inactivity, and as little as a single bout of resistance exercise can transiently reverse insulin resistance (5).
Translation: Lift weights…manage your blood sugar better…don’t get your toes amputated.
Now we’ve seen some evidence for not only maintaining, but INCREASING your muscle mass. Ready for some more? Tune in next week for the second part of this article as we continue The Muscle Movement. Learn why you should start implementing weight training right now to add years onto your life.
Yes, shut your laptop and pick up a dumbbell.
Cahill GF Jr. Starvation in man. N Engl J Med 1970:668 –75
Cooper C. The crippling consequences of fractures and their impact on quality of life. Am J Med 1997;103:125–75
Pereira CT, Barrow RE, Sterns AM, et al. Age dependent differences in survival after severe burns: a unicentric review of 1674 patients and 179 autopsies over 15 years. J Am Coll Surg 2005
Itani SI, Ruderman NB, Schmieder F, Boden G. Lipid-induced insulin resistance in human muscle is associated with changes in diacylglycerol, protein kinase C and IkB-?. Diabetes 2002;51:2005–11.
Rasmussen BB, Fujita S, Wolfe RR, et al. Insulin resistance of protein metabolism in aging. FASEB 2006;20:768 –9.