Muscle Mass Matters
If you want to stay healthy, maintain your muscle mass. Muscle mass is an indicator of one’s heath status. The weight of skeletal muscle represents muscle mass. Muscle mass can make up 40% of one’s total body weight. We typically use the Body Mass Index or BMI as a health indicator. It is simple to determine as it is based on one’s weight and height. A high BMI is felt to be unhealthy. But, is it?
BMI attempts to determine if your weight is appropriate for your height, but 20% of the population has a BMI that is misleading. The reason BMI can be misleading is that it does not differentiate between fat and muscle. One can have a high BMI because one is fat, or one can have a high BMI because one is very muscular. Thus, BMI does not tell the whole story. What is needed is knowledge of body composition – how much fat and how much muscle does a person have. One can be skinny fat and overweight muscular.
A study published in the American Journal of Geriatrics found that a high BMI (> 27 Kg/m²) in the elderly was not significantly related to mortality but a low BMI (< 22 Kg/m² was associated with higher mortality rates. In the elderly, a low BMI is nearly universally due to low muscle mass.
So muscle mass matters.
A review published in the Annals of Medicine looked at 140 studies performed in several settings (outpatient, inpatient, and long-term care facilities) and concluded that people with low muscle mass had more surgical complications, longer hospital stays, lower physical function, poorer quality of life, and overall lower survival.
So muscle mass does matter!
Health Benefits of Muscle Mass
What are the health benefits of muscle mass?
Muscle mass improves body strength and endurance improving quality of life. Muscle mass improves blood sugar control. The more muscle you have the more insulin receptors you have (insulin is a hormone that regulates blood sugar control) as insulin receptors are found on muscle cells. Muscle mass improves bone density decreasing the risk of developing osteoporosis in men and women.
Cancer outcomes are better in patients with higher muscle mass. Cancer patients with sarcopenia (advanced loss of muscle mass) had a 41% greater risk of dying.
Subtle Signs of Loss of Muscle Mass
There are several subtle or soft signs that indicate a loss of muscle mass. These include a lack of grip strength, fatigue, slower walking speed, and intentional weight loss, and decrease general strength. We could consider muscle mass as a vital sign of health. A study published in the British Medical Journal (BMJ) concluded that grip strength is a better predictor than blood pressure or BMI in determining risk of heart disease and overall mortality.
How to Measure Muscle Mass
The best current available tools to measure muscle mass is DEXA scan which is routinely used to measure bone density. It can tell how much muscle mass one has per body part, therefore, the left leg, right leg, trunk, left arm, right arm, etc. Muscle can also be measured via CT and MRI imaging and handheld ultrasound and bioelectrical impedance (BIA) devices. Many bathroom scales now use BIA technology.
Building Muscle Mass
Fortunately, muscle is a forgiving organ and can be regained once lost. Three things are needed for building muscle mass: diet with adequate protein, physical activity, and adequate hormone levels. We have addressed these three areas in numerous posts.
To maintain muscle mass consume leans sources of beef, poultry, or wild game. Eggs are a greats source of protein, too. Nuts and seeds are convenient sources of protein and make for great in between meals snacks. Protein shakes are another great option.
A study in Applied Physiology, Nutrition, and Metabolism concluded that consuming a single serving of 6 ounces of lean ground beef is best for maintaining muscle mass in men over 50. This amount of protein is double the standard recommendation for protein consumption. That earlier recommendation, however, was merely the amount of protein to prevent a protein deficiency. The six-ounce recommendation is based on the amount of protein to maintain muscle mass.
Carrying out our activities of daily living requires a certain threshold of muscle strength – getting out of chair, climbing a flight of stairs, moving a piece of furniture, assisting another person, for example. As simple or basic as these activities seem, they become increasingly challenging with aging. Don’t let muscle weakness affect your quality of life.
Strength or resistance training involves the performance of exercises to improve muscle strength. Resistance training can be performed any number of ways including the simple use of one’s own body weight. The more common methods of resistance training involve the use of machines, weights, or resistance bands. As greater resistance or higher loads are lifted the higher the gains in muscle strength.
There are far more health and fitness benefits of resistance training than is appreciated. Below are some of the benefits.
- Improved quality of life
- Improved muscle strength
- Improved balance
- Improved bone density
- Improved blood glucose and insulin sensitivity
- Improved body composition
- Decreased cardiovascular risks
The older we become the more important resistance training becomes. The reason for that is as we age we tend to lose muscle and muscle strength. This loss of muscle is called sarcopenia. This loss in strength is in part related to a general lack of muscle use commonly seen as we age, but it is also related to declining hormone levels especially testosterone, DHEA, and growth hormone. Declines in these hormones adversely affect men and women as they age.
Speaking of hormones.
Hormones and Muscle Mass
There is a direct correlation between testosterone levels and muscle mass. So it’s not surprising that we lose muscle and become more frail as our testosterone levels decline with age, and that’s true for women, too. One fairly easy way to tell if a woman is relatively low in testosterone is to look at her thighs and triceps (back of upper arms). Does she have the flabby arm and thigh syndrome?
Testosterone is needed to build muscle in response to strength training. If testosterone levels are low then one will see a limited response to strength training. That’s why prepubescents don’t bulk up with strength training – though they do get stronger mainly from neuromuscular mechanisms.
The take home message of this article is MAINTAIN YOUR MUSCLE MASS.