Disease, aging and inactivity will make your muscles atrophied. There will be less nutrient absorption and blood flow as your muscles shrink. Several treatments can help fight muscle atrophy. However, you should speak with your healthcare team before self-diagnosing or treating this medical condition.
Read more: Signs & Symptoms of Muscle Wasting
Understanding Muscle Atrophy's Epidemiology
Muscle atrophy appears as a result of many medical conditions, ranging from sports injuries to cancerous tumors. However, the greatest prevalence appears in older adults. Doctors refer to age-related muscle atrophy as sarcopenia. Nearly 1 in 3 older adults in the U.S. meets the criteria for this disease, according to a 2017 report in the journal Bone. This ratio rises to 1 in 2 by age 80.
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Understanding Atrophy's Timeline
People think muscle atrophy occurs after a long period of inactivity. Yet, it happens relatively fast. A 2016 report from Maastricht University looked at atrophy's timeline in healthy adults during a restricted movement protocol.
Participants had a single leg immobilized for two weeks. Compared to the free leg, the subjects showed leg atrophy — a 3.5 percent loss in their thigh mass within five days. They also showed a 9 percent loss in their muscle strength during that same time period.
Understanding Atrophy's Anatomy
You have different types of muscle tissue. Type I fibers contribute to endurance activities, while type II fiber contributes to strength activities. Demographic variables correlate well with the type of muscle atrophy seen. A 2013 article in Current Opinion in Clinical Nutrition and Metabolic Care looked at the molecular mechanisms involved in muscle atrophy.
The author noted that inactivity mostly affects type I fibers, and that disease mostly affects type II fibers. There's also a dramatic shift as you age. Postmenopausal women, for example, often have high levels of type II muscle atrophy.
Understanding Atrophy's Signs
Many medical conditions predispose you to developing muscle atrophy, according to a 2016 paper from the University of Iowa. Malnourishment, organ failure and AIDS often lead to atrophy. Injuries like burns also lead to a wasting syndrome known as cachexia. Working at height or in outer space can trigger muscle atrophy as well.
Understanding Atrophy's Mechanisms
Many factors combine to cause muscle atrophy, according to a 2015 review in the Journal of Muscle Research and Cell Motility. The organelles, cytoplasm and proteins decrease in the affected muscle. This loss causes a decrease in muscle size. You also deplete the muscle-building proteins — myosins — in that area.
These changes make the muscle more vulnerable to toxins that increase inflammation. Elevations in blood sugar — hyperglycemia — may also play a role. The muscle is also at risk for infection and even auto-immune disease.
At the molecular level, proteins are breaking down faster than they can be rebuilt in an atrophied muscle. Your first response to these losses is a perceived loss of strength. That is, initially, your muscles can theoretically produce the same force, but you may have developed exercise intolerance. Over time, you will lose both the physical and mental control of atrophied muscles.
Understanding Atrophy's Symptoms
Symptoms of muscle atrophy include a decrease in muscle strength and muscle size as well as an increase in muscle fatigue. Behaviorally, you'll lose weight and feel tired. Diagnostic tests will show high levels of free radicals and GDF11.
Understanding Atrophy's Consequences
People with muscle atrophy have a greater risk of musculoskeletal disorders like spinal curvature. Yet, muscle atrophy has even more serious clinical consequences, including a decrease in physical activity and life quality. It also increases your risk of disease and death.
Your body often replaces shrinking muscle with unwanted connective tissue and fat cells. This process works in reverse, as well. Obesity facilitates muscle atrophy through a complex array of biochemical changes. Accumulating body fat places you at risk for heart disease, diabetes and stroke.
Interestingly, the short periods of immobilization that you experience throughout your life such as hospitalization and bed rest may have long-term consequences. These periods may accumulate and trigger sarcopenia later in your life.
Understand Atrophy's Treatments
Fortunately, some muscle fibers remain in nearly all cases of muscle atrophy. This finding gives you the opportunity to rejuvenate long-lost muscles. Resistance exercises targeting the atrophied areas give you the easiest path to success, but nutritional supplements and electrical pulses may work too.
Read more: How to Regain Muscle Mass
Fight Atrophy with Team Sports
Recreational activities give you an excellent way to keep your health as you age. Team sports, for example, can help you stay nimble, limber and fit. They have other benefits as well. A 2017 report in PLoS One looked at the impact of team sports and protein intake on the muscle mass of previously inactive older adults.
Participants played 20 minutes of floor ball (similar to hockey, but indoors) or cone ball twice a week for 12 weeks. They also consumed 18 grams of protein after each session. Compared to controls, the subjects gained more than a pound of muscle mass in their legs. These positive results led 75 percent of the participants to keep playing the soccer-like games after the study ended.
Some older adults avoid team sports because they fear getting injured. Only 6 percent of the subjects in the PLoS One study experienced an injury, and most sports injuries are minor. Yet, older adults remain at risk for injury due to poor conditioning and functional asymmetries.
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Fight Atrophy With Resistance Exercises
Resistance exercises can address the lack of conditioning in older adults. Adding weightlifting, for example, to your weekly routine will improve your physical and mental health. This change should also increase your muscle mass.
A 2017 paper in the Journal of Strength and Conditioning Research tested this hypothesis in older women: Subjects lifted weights once a week for eight weeks. Compared to controls, women in the treatment group showed a 3.6 percent increase in muscle mass. Surprisingly, hormone levels stayed constant throughout the study. Thus, the mechanisms underlying these anabolic effects in older women remain unknown.
A 2017 thesis from California State University stated that doing resistance exercises causes fewer injuries than participating in sports. The author also showed that quality supervision — like that given by a coach — lowers your injury risk while training. Using a personal trainer also increases attendance, tolerance and enjoyment in older adults doing resistance exercises, according to a 2018 report in Qualitative Research in Sport, Exercise and Health.
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Combat Atrophy with Macronutrients
Poor protein metabolism plays a major role in causing muscle atrophy. Thus, increasing your protein intake should help you combat muscle atrophy. A 2018 study in the American Journal of Clinical Nutrition evaluated this possibility in older adults at risk for frailty.
Participants received twice the recommended daily allowance, RDA, of protein each day for 12 weeks. The current RDA in this age group is 0.8 grams per kilogram of body weight. That intake caused a 1-pound increase in their muscle mass, compared to controls. The subjects didn't report side effects.
Read more: Pros & Cons to Muscle Mass Supplements
Combat Atrophy with Micronutrients
Vitamin deficiencies may also play a role in muscle atrophy. For example, vitamin D has a critical impact on muscle development and muscle growth. Using supplements to correct vitamin deficiencies should have a positive effect on muscle mass. A 2015 report in Osteoporosis International tested this idea in relatively young, postmenopausal women.
The subjects received oral doses of vitamin D or a placebo each day for 36 weeks. Women in the placebo group lost muscle mass during this time. In contrast, women in the supplement group kept their muscle mass throughout the experiment. Women in the supplement group also increased their muscle strength.
This study used large — 1,000 I.U. — doses of vitamin D. A 2018 review in Diabetes and Metabolic Syndrome suggested that such large doses seem necessary to increase the fitness levels of older women. However, the Office of Dietary Supplements recommends a daily dose of only 600 I.U. in this age group.
Excess vitamin D may have toxic effects, so speak with your doctor before taking it.
Beat Atrophy with Electrical Pulses
Other methods beside physical activities and dietary aids can help reverse muscle atrophy. For example, personal trainers have used electromyostimulation to help athletes recover from injury. These interventions cause only small changes in muscle mass, and those effects take weeks to happen. Yet, this finding suggests that electrical stimulation can help you beat atrophy.
The 2016 report from Maastricht University showed that neuromuscular electrical stimulation can reverse the muscle atrophy caused by leg immobilization. This technique can also prevent muscle loss seen in comatose patients and older adults. In fact, the author of a 2015 paper from Keele University suggested using electrical stimulation to prevent age-related muscle atrophy before it happens.
- Bone: Review of Sarcopenia
- Maastricht University: Interventional Strategies to Combat Muscle Disuse Atrophy
- Current Opinion In Clinical Nutrition And Metabolic Care: Mechanisms For Fiber-Type Specificity Of Skeletal Muscle Atrophy
- University of Iowa: Molecular Pathogenesis of Skeletal Muscle Atrophy
- Journal of Muscle Research and Cell Motility: Skeletal Muscle Atrophy
- PloS One: Effect of Small-Sided Team Sport Training and Protein Intake on Muscle Mass, Physical Function and Markers of Health in Older Untrained Adults
- Journal of Strength and Conditioning Research: Effects of Traditional and Pyramidal Resistance Training Systems on Muscular Strength, Muscle Mass, and Hormonal Responses in Older Women
- California State University: Prevalence of Formal Education, Certification, and Continuing Education Specific to Resistance Training Among Public High School Physical Educators in California
- Qualitative Research in Sport, Exercise and Health: 'I Have a Renewed Enthusiasm for Going to the Gym’
- American Journal of Clinical Nutrition: Protein Supplementation Improves Muscle Mass and Physical Performance in Undernourished Prefrail and Frail Elderly Subjects
- Osteoporosis International: Effect of vitamin D Supplementation Alone on Muscle Function in Postmenopausal Women
- Diabetes and Metabolic Syndrome: Can Vitamin D Supplementation Alone Effective to Increase a Physical Fitness Levels in Post-menopausal Women With Metabolic Disorders?
- Office of Dietary Supplements: Vitamin D Fact Sheet for Health Professionals
- Keele University: Role of Neuromuscular Electrical Stimulation in Reversing Age‐related and Pathological Muscle Atrophy