The human body has over 650 muscles. Skeletal muscle is the body’s largest tissue accounting for approximately 45% of body weight in men and 36% in women.

Muscles are comprised of muscle fibers. Each fiber is thinner than a human hair and can support up to 1,000 times its own weight.

Every human movement is a sequence of skeletal muscle contractions woven seamlessly together by means of a complex interaction between the body’s muscles and the nervous system.

Classified according to the duties it must accomplish in the body there are three distinct types of muscle, cardiac, smooth and skeletal.

Cardiac muscle, found only in the heart. Smooth muscle consists of slender, cylindrical fibers which are aligned parallel to form sheets of muscle. Most smooth muscle is visceral (it surrounds nearly all of the body’s organs). Skeletal muscle fibers (elongated cylinders) are bundled into groups, which are then bundled together to form what most people refer to as “muscle.”

Anchored to bones, skeletal muscle pulls on them to cause the movement to occur.

One of the many reasons why I don’t assume anything about aging is that we need to maintain muscle to move our bones and our body! When people age without maintaining muscle mass the function is lost. Balance becomes a problem and falling occurs. Muscle contributes to the functioning of both and much more.

Between the third and eighth decades of life, without muscle maintenance, people lose up to 15% of our lean muscle mass, which contributes to a lower metabolic rate. These problems have a major impact on our quality of life and health.

Maintaining muscle strength and mass helps burn calories to maintain a healthy weight, strengthens bones, and restores balance, decreasing falls. The National Institutes of Health estimates more than one-third of people over the age of 65 fall each year, often resulting in injuries such as hip fractures which are a major cause of surgeries and disability among the elderly. Balance and strength exercises can help maintain balance and reduce this risk of falling, as well as building bone.

Muscles help to improve posture, circulate blood through the body, regulate breathing, generate heat, stabilize joints, aid digestion and protect vital organs.

The body is responsive to strength training at any age. In other articles on my site I have written about researchers who have gone into nursing homes and restored resident’s ability to get rid of walkers and stand up when getting out of a chair. The benefits are tremendous. Nothing about aging should ever be assumed! Muscle has memory and when retrained it benefits our overall health and functioning. It is the best contributor to longevity that we know of!

Strength doesn’t just involve building large muscles. Lifting weights just two or three times a week can increase strength by building lean muscle. Studies have shown that even this small amount of strength training can increase bone density, overall strength, and balance. It can also reduce the risks of fractures which often occurs when falling.

Just as muscle mass declines (when not maintained) so does endurance. The good news is that the body also responds to endurance fitness training such as walking. Any activity that increases heart rate and breathing for an extended period is considered endurance exercise. In addition to walking, swimming, cycling, dancing, and tennis are all endurance activities.

Your metabolic rate is strongly influenced by our body composition. People with more muscle and less fat generally have a faster metabolic rate, while people with more fat and less muscle generally have the opposite, a slower metabolism. Every pound of muscle uses about 6 calories a day just sustain itself. While each pound of fat burns only 2 calories daily. That small difference adds up over time. After a session of strength training muscles are activated all over your body, raising your average daily metabolic rate. One pound of muscle occupies around 22% less space than one pound of fat.

Unless you are an elite athlete, resting metabolism accounts for 60% to 75% of all the calories you burn each day, and it varies a lot from person to person.

Other benefits for muscle building is better sleep. Researchers have known that short sleep leads to weight gain. People who don’t get at least 6 hours of sleep at night are prone to overeating, and they usually crave starchy, sugary foods. Also not enough sleep slows metabolism.

Researchers at the University of Pennsylvania studied 36 healthy adults into their sleep study. Even though the sleep-restricted group was active and awake for more hours of the day, their resting metabolisms slowed by about 50-60 calories a day, says senior study author Namni Goel, PhD. Goel studies sleep medicine at the University of Pennsylvania School of Medicine.

It isn’t a huge amount, but “That can add up across multiple nights of sleep restriction.” she says. Her sleep-restricted volunteers were eating around 500 more calories each day, so the total calorie imbalance just from not getting sleep was substantial – around 550 calories a day, enough to lead to about a pound of weight gain each week.

Will you fight the assumptions of aging by improving your overall health? Include muscle function and you’ll be well on your way to aging well.  Remember Ernestine Shepherd? i wrote about her last month and in other articles. She started body building at the age of 56. She is now 81! She wakes up at 2:30 a.m. every morning, consumes 10 egg whites then goes for a 10 mile run. I suspect part of her remaining day is at the gym! While everyone can’t do this, but whatever time spent is a contribution to our longevity!