Category Archives: Exercise

Insight 5 – Optimizing Balance

Exercise, Individual controls aging, , , , ,

Benefits of a stable balance

Good Balance

Good balance is absolutely essential to prevent falls.  Reliable balance also assures an optimal comfortable walking pace.  Results of clinical trials tells us that strength and balance exercises will definitely help us avoid falls and get us safely from point A to point B.  In other words, you can minimize your risk of falling and improve your walking pace through a proven exercise program (given below).  On the other hand, ignoring these exercises will guarantee a high risk of falling and bring on an abundance of unwanted consequences.

Balance depends on biology that changes with age

Balance deteriorates with age.  There are many reasons for this.  Firstly, declining sight and hearing contribute to poor balance.  Secondly, years of poor posture exacerbated by weak back muscles and loss of bone mass produce a compressed spine or a “hunched” back that reduces upright stability.  Thirdly, the sense of touch and the sense of muscle/joint position decline and hence need to be retrained.  Reduced sight and hearing may be readily improved with correctives lenses and hearing devices but sadly these are often ignored.  Other decrements are best minimized through resistance and balance exercises.  Age-associated decline in balance is modifiable; modifications will definitely build longevity by lengthening the health span.

The cost of a fall is high

Approximately thirty percent of elderly fall at least once a year.  Avoiding a fall is of paramount importance because the consequences of a fall are all negative.  The least negative might be a sore muscle but more commonly, it is a broken bone e.g. hip.  Broken bones require hospitalization, medical expenses, and significant recovery time that limit independence.  Hip fractures are especially harmful since they are associated with an elevated risk of dying, a risk which persists for years after the fracture.  Another outcome after a fall is onset of an unavoidable psychological mentality called “fear of falling”.  This plays a role in producing a slower, more cautious gait that unfortunately is incredibly damaging in the long run. 

The cost of slowed gait is high

Poor balance leads to an unsteady, hesitant walking gait.  This compromises posture and reduces further the existing poor balance.  This downward cycle favors a fall.  Slowed gait also limits mobility and independence.  Performance of daily tasks take more time and therefore, become more difficult.

Balance exercises are part of the 4-Prong Exercise Program

Previous blogs discussed progressive resistance exercises, aerobic exercises, and stretch exercises.  Additionally they discussed the validity of these exercises to modify various age changes, to increase the health span and to build longevity.  The final essential exercise to add to the preceding 3 is balance.   Balance exercises are critically important for retraining the sensory perception pathways in the joints and muscles of the feet, ankles, legs.  Balance exercises need to partner with specific resistance exercises to be totally effective in optimizing balance and preventing falls. 

Evidence to show balance exercises works

Results of several clinical trials provide evidence that specific balance exercises coupled with moderate intensity lower limb resistance exercises improve balance stability and reduce the risk of falling.  These trials (both sexes, community dwellers, 65 years and older, one study with women with osteoporosis) employed several standardized tests to measure balance before and after the interventions (resistance and balance exercises for 6-12 months) and traced the incidence of falls in the control and exercising groups.   

Exercises to improve balance; balance type

Here are the balance exercises used in the clinical trials mentioned above.  Balance exercises are initially practiced for 10 seconds and increased over time.  The more practice, the better the improvement in balance.

(1) standing with one foot directly in front of the other;

(2) walking placing one foot directly in front of the other;

(3) walking on heels;

(4) walking backwards, sideways and turning around;

(5) stepping over objects;

(6) bending and picking up an object;

(7) stair climbing in the home;

(8) rising from a sitting position to a standing one;

(9) knee squat.

Exercises to improve balance; resistance type

Here are the resistance exercises used in the clinical trials noted above and shown to be successful in improving balance in the elderly and decreasing risk of falling.  They are the (1) hip extensor, (2) hip abductor, (3)  knee extensor, (4) knee flexor, (5) inner quadriceps, (6) ankle plantar and (7) dorsiflexor muscle exercises.  These exercises are fairly simple to do and are described below.  They should be initiated without ankle weights and one set of 10 repetitions.  When ready, add an ankle weight of 1 pound and progress up to 6 pounds; increase the number of sets.   The greater the weight and the number of sets, the better the improvement in balance. The combination of  balance and resistance exercises are performed a minimum of 3 times a week for approximately 30 minutes.

Specific resistance exercises proven to improve balance

1.  Hip Extensor

     stand 12-18 inches from table

     bend at hips: hold onto the table

     slowly lift one leg straight backwards; hold position

     slowly lower leg

     repeat with other leg

2.  Hip Abductor

     stand near table; hold onto table

     move straight leg sideways away from body; hold position

     slowly lower leg

     repeat with other leg

3.  Knee Extensor

     sit in a chair with your back and hips against back of chair.

     keep knees at 90 degree angle, resting toes on ground

     in a 1-2 up count,  extend your left leg straight out parallel to the ground

     pause for 1 second

     in a 1-2-3 down count, slowly lower your leg back to 90 degrees

4.  Knee Flexor

     stand behind chair, resting hands on back of chair, facing forward, keep head in line with spine, place feet shoulder-width apart, pelvis level with knees slightly bent

      in a 1-2 up count, bend left leg to bring up heel toward buttocks as high as possible

      pause for 1 second

      in a 1-2-3 down count, lower left heel to ground

5.  Inner Range Quadriceps

     sit on ground with knee bent over a rolled up towel

     tighten up knee muscles and lift heel off ground; keep knee on rolled up towel

     hold for 5 seconds, getting heel as high as possible

     start with large rolled up towel and gradually decrease size of roll

6.  Ankle Dorsiflexor

     sit on chair with feet touching floor

     leave heel on floor and tap toes up and down

     Alternative – using elastic stretch band of comfortable resistance

     sit on the floor with legs straight out in front

     anchor elastic band to a chair or table leg and wrap around foot

     pull toes toward you and slowly return to start position

7.  Ankle Plantar Flexion

     sit on chair with feet touching floor

     leave toes on floor and lift heel up and down

     Alternative with elastic band

     wrap elastic band around foot and hold the ends in your hands

     gently point toes and slowly return to start position

Insight 4: Anti-aging benefits of aerobic and stretch exercises

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Aging of heart, blood vessels, chest, lungs and brain is significantly retarded with aerobic

A program of progressive resistance training (PRT) that reduced age-dependent loss of skeletal muscle mass and strength was discussed in the previous blog.  Three other types of exercises of considerable importance are  1)  aerobic, 2) stretch and 3) balance exercises, and together with PRT, provide a comprehensive exercise program for the older adult.  As with PRT, these additional 3 exercises  have been validated in clinical trials to retard specific age changes and enhance physical function.  For that reason, this blog will focus on the benefits of aerobic and stretch exercises and define how each should be performed to achieve maximal health results.  Balance exercises improve different age-related deficits and consequently will be discussed separately in another blog.

Age changes prevented/slowed with aerobic and stretch exercises

One’s ability to engage in physical activity or activities above rest e.g. climbing stairs, shopping, catching a bus, running on the track, requires enhanced coordinated efforts from many organ-systems.  Consider the most noteworthy changes:

What happens in the heart

 a) there is a stronger and more forceful heart beat to assure that more blood is pumped to key organs e.g. skeletal muscles, lungs and also the heart;

What happens in the blood vessels

 b) there is an improve compliance (flexibility) of blood vessels to keep blood pressure adequate for delivery of  elevated levels of oxygen and removal of carbon dioxide and other waste products;

What happens in the lungs

c)  there is an increase the rate and depth of each breath by forceful contraction of the chest, diaphragm and abdominal muscles to capture more oxygen and expel more carbon dioxide;

What happens in the leg muscles

 d) there are more rapid and forceful contractions/relaxations of mainly the large skeletal muscles of the legs. 

Peak performance declines with age but more so with a sedentary lifestyle

This multiplicity of events, at its peak performance level for any one person, is referred to as maximal oxygen consumption. Since maximal oxygen consumption can be measured fairly accurately, it has been for decades a popular number for scientists to assess.  It basically represents the level of physical fitness of an individual.  Thus there is a considerable amount of information defining the change in maximal oxygen consumption (or fitness) over time.  In particular, fitness declines with age in everyone but significantly less so in older adults engaged in an aerobic program for most of their adult life.  Regrettably and because of this, elderly with a sedentary lifestyle will experience a dramatic inability to engage comfortably in all physically activities above rest. Physical activity will be cut short by rapid onset of fatigue. 

Without chronic aerobic exercise, heart, blood vessels, lungs and leg muscles slowly fail

In the absence of aerobic exercise, an age-related decline in VO2max occurs for several reasons:  both the heart and large blood vessels (carotids, aorta) become less compliant e.g. stiffer over time.  This causes the heart to work harder even at rest.  Additionally, the small blood vessels with time lose their ability to produce an essential vasodilator (EDRF) that had assured increased blood flow when younger.  Without EDRF, key organs (heart, lungs, brain, skeletal muscles) are deprived of requisite oxygen and nutrients and hence tissues/organs cannot handle the demands inherent in physical activity.  The lungs and chest also become harder to  inflate and deflate due to factors such as  loss of chest and lung flexibility but also muscle weakness (dynapenia).   These are  guaranteed age-associated changes in the absence of aerobic exercises.

Proven benefits of aerobic exercise

Unlike resistance exercises, the number of older adults that participate regularly in aerobic exercises is significantly greater (approximately 40% age 65-74, 30% 74-84 and 20% >85*) and this is a good thing.   However, considering the multitude of benefits, this degree of participation  remains disappointing. 

Aerobic exercises include activities such as jogging/running (outside or treadmill), cycling (outside or stationary), swimming, dancing, and walking.  Results of literally thousands of interventional clinical trials, observational and epidemiological studies point to an abundance of benefits of  regular aerobic exercise.  All the benefits listed have been documented numerous times.  Benefits of regular aerobic exercise are:    

Blood vessel transport blood more easily

1)  reduction in age-dependent stiffening of major arteries allowing greater capacity of arteries to stretch and secondarily to reduce the workload on the heart; lower resting heart rate promoting more efficient heart pumping

Exchange of nutrients, gases and waste products is more efficient

2)  tissues/organs are healthier due to better flow of oxygen in and waste products out resulting in less inflammation and cellular damage; especially beneficial to the brain leading to improved cognition, reduced risk of mild cognitive impairment, depression, anxiety

Control of blood sugar is improved; fats and “bad” cholesterol are lowered

3)  metabolic benefits of improved blood sugar control, reduction in body fat, favorable lipid profile with low levels of free fatty acids and higher levels of HDL (“good cholesterol”), weight maintenance or loss

More energy for all activities

4)  decrease in fatigue (the older adult tires less easily, remains physically active for longer periods of time)

Reduced levels of stress

5)  increase in ability to handle stress ( the older adult exhibits better outcomes following surgery e.g. shorter hospital stay, faster recovery) 

Reduction in risk for many diseases

6)  reduction in risk for diseases including cardiovascular disease, type 2 diabetes, Alzheimer’s disease and frailty (condition of increased weakness predicting imminent death

Assured independence and quality of life

7)   increase in quality of life supporting continued independence 

Aerobic exercises – how to get the most out of them

Each person should select the aerobic activity of interest.  For sedentary elderly initiating a program, it is prudent to first discuss an exercise program with your physician and then to begin slowly with a progressive stepwise increase in intensity.  As with PRT, the goal with aerobic exercises is to gradually do more by increasing time or energy spent.   As several recent studies have shown, anti-aging health benefits are proportional to the input. 

Ideally, aerobic exercises are performed five times a week for 30 minutes or more depending on the level of intensity (55-90% of a maximal heart rate or 12-and above on a perceived exertion scale given in Table 1 in PDF 1).  Maximal heart rate can be calculated by multiplying one’s age by 0.7 and subtracting that number from 208.  Table 2 in PDF 1 shows the required exercise duration based on intensity.

PDF-1-Borg-Scale-Aerobic-intensitiesDownload

An alternative to standard aerobic exercise is high intensity interval training (HIIT)

The Mayo Clinic*** in an impressive study about 3 years ago reported that 12 weeks of high intensity interval training (HIIT) provided huge benefits for the elderly.  In this study, volunteers in 2 different age groups  (18-30 yrs and 65-80 yrs) performed the following:  a) high intensity interval training, 3x weekly + 2x weekly of treadmill walking, b) resistance training, 2x weekly and c) sedentary period followed by combined training of moderate-intensity aerobics, 5x weekly + 4x weekly resistance training . 

HIIT in this study consisted of stationary cycling for 4 minutes at > 90% maximal oxygen intake (high intensity), followed by 3 minutes reduced intensity (no resistance), followed by 4 minutes of maximal oxygen intake, followed by 3 minutes of no resistance.  This was repeated two more times yielding total time investment of 25 minutes.   

Benefits of HIIT

HIIT results outperformed the other two exercise protocols by providing the following:

a)  highest level of improved cardio-respiratory fitness (optimal heart and lung function), increased insulin sensitivity (lower blood sugar levels), enhanced mitochondrial respiration (improved function of cells with evidence of reversal of age changes), and decreased fat-free mass  (loss of body fat) in both young and older age groups.

b)  similar but lesser effects were observed in groups undergoing resistance training and combined training.  It is concluded that HIIT is a more effective means of reversing aging of the heart, blood vessels, chest , lungs and skeletal muscles.  Thus it can substitute for vigorous exercise listed in Table 2.

Benefits of stretch exercises

Performance of stretching or flexibility exercises is the best way to:

a)  improve range of motion of the joints,

b)  increase agility and speed in physical activities,

c)  reduce injury of muscles and joints.

In addition to the above, other benefits from adherence to a stretching protocol have been observed:  lowering of blood sugar in individuals with Type 2 Diabetes, reduction in frequency and intensity of nocturnal leg cramps.

Stretching to accompany aerobic exercises

What are stretch exercises?

Stretch exercises are an excellent companion to aerobic exercises.  Performance frequency for stretch exercises is under debate.  Suggestions range from twice daily every days to the traditional advice of stretching before and after aerobic exercises (5 days a week).  Recently, it was found that maximal benefit is achieved with stretching after a session of aerobic exercise and in this case, a warm-up (exercising at a low intensity) prior the aerobic exercise session is recommended to replace the stretch exercises.  There are two types of stretch exercises:  static and fluid (dynamic).  Static stretching is maintaining a slow and controlled continuous tension to a muscle group(s) while fluid stretching requires tension on specific muscle groups while taking them through a full range of motion.  

How to get the most out of stretch exercises

Total stretching time with a variety of stretches is the important determinant that improves range of motion and reduces injury.  This is more influential than the length of time a stretch is held or the number of repetitions.  Optimal stretch time per muscle group is generally 30 seconds.  As with other exercises, the gain in benefit (range of motion, flexibility etc) with stretching declines over time when the protocol is stopped.   

There are many static and fluid stretches for both upper and lower body muscles.  The following videos provides excellent examples to incorporate into a stretch protocol following an aerobic workout.

Videos demonstrating stretch exercises

PDF-2-Selection-of-stretch-videosDownload

* Data from surveys and household interviews (2013-2015) reported by Centers for Disease Control and Prevention September 23, 2016 / 65(37);1019

** Borg GA.  Psychophysical bases of perceived exertion.  Med Sci Sports Exerc 14:377-381, 1982.

*** Robinson et al., Enhanced Protein Translation Underlies Improved Metabolic and Physical Adaptations to Different Exercise Training Modes in Young and Old Humans Cell Metabolism 25: 581–592, 2017

Insight 3: Ways to retard skeletal muscle aging

Exercise, Individual controls aging, , , ,

Regular Progressive Resistance Training is the answer

So what can the older adult do to assure continued independence, normal weight and avoid a fall and Type 2 Diabetes?  Results of over hundreds of clinical trials conclude that regular progressive resistance training (PRT) is the answer.  This is the way the to retard skeletal muscle aging. Although this strategy has been in the scientific literature for near 30 years, surprisingly and sadly, very few adults follow an exercise program that includes resistance exercises (in the US population, an estimated 5% participate in resistance exercise versus more than 50% that engage in an aerobic regimen e.g. walking, swimming, jogging).  An additional piece of advice, stemming directly from clinical trial results, recommends the ingestion of 20-35 grams of quality protein post PRT workout to maximize the benefit gained from the resistance training alone. 

Progressive resistance training to retard skeletal muscle aging?

So what exactly is progressive resistance training (PRT)?  Simply, it is strength and speed training against a resistance which is either free weights e.g. dumbbells or barbells, weight machines (gravity resistance), calisthenics e.g. squats (body and gravity resistance) and/or use of resistance elastic bands or tubes.   In starting a program of PRT, consideration is given not only to the  type of resistance as just indicated but also, target muscles, frequency of exercise, intensity, and repetitions. 

Liu and Latham (2015)* reviewed 121 clinical trials with over 6,000 participants and concluded  that ” Doing PRT two to three times a week can improve physical function in older adults, including reducing physical disability, some functional limitations (i.e. balance, gait speed, timed walk, timed ‘up-and-go’, chair rise; and climbing stairs) and muscle weakness in older people.”  The average age in these studies ranged from 61 to 88 years.   Approximately half of the studies enrolled healthy sedentary older adults; the remainder were comprised of older adults with physical disabilities or limitations.   PRT lasted anywhere from 10 weeks to 2 years, targeting different muscle groups with increasing intensity.   It is noteworthy that older adults of any age, with or without physical limitations, will benefit from PRT.

A reasonable progressive resistance training program

What is an example of a successful PRT program?  A reasonable PRT program, based on results of interventional studies discussed above, has been developed for beginners, intermediate and advanced participants (Law et al., 2016)*.  The program is given below (PDF 1).  Target muscles are those of the chest, back, arms, shoulder, upper legs and lower legs.  For beginners, the program is 8 weeks in duration, twice weekly. Phase 1 (2 weeks) requires exercises at an intensity of 50-60% of one maximal repetition (RM) with performance of one exercise set with 12-15 repetitions.  For weeks 3-8,  the intensity increases to 60-69% of 1RM, the repetitions increase to 18, and a new exercise set is added. 

Ideally start with weight machines and trainer

Law et al., (2016) favors starting with weight machines and ideally a trainer to assure that the correct form is achieved for each exercise.  It is also advisable to discuss a new exercise program with your physician before setting forth.  The sample program for intermediate and advanced PRT modifies the beginner program and adds new exercises with increases in both intensity, sets and repetitions.  In lieu of weight machines, there are reliable established  free videos on strength training with dumbbells (PDF 2), and alternative exercises e.g. calisthenics and elastic bands (PDF 3)).  Remember the program must be progressive to be of benefit and hence must increase in intensity over time.

Progressive resistance training and protein supplementation are proven means to minimized age-associated sarcopenia and dynapenia.

To maximize the benefits of PRT, findings from numerous studies, albeit with a small number of volunteers, show that consumption of high quality protein e.g. soy or whey (20-35 gm) or essential amino acids leucine and isoleucine (3.5 gm) stimulates skeletal muscle formation and leads to better outcomes (mass, strength, performance) than PRT without protein supplementation.  Leucine and isoleucine cannot be synthesized by the body so both must be ingested. Leucine and isoleucine are the amino acids most adept at encouraging exercised muscles to up their production of major muscle proteins e.g. myosin.  Protein supplementation is based on studies with volunteers, 55-85 years of age, of various weights (normal to obese) who performed resistance exercises  (hand held weights and machines) for 10-26 weeks, 2-3 x per week, multiple target muscles with 3 sets of 8-12 repetitions at 70-85% maximal repetition.  

Do not forget protein supplementation

PRT plus protein supplementation is the anti-aging strategy that is definitely in sync with living a longer healthier life.  Consider the wealth of benefits from this strategy:  strength to perform all desired daily activities, avoidance of physical disabilities, maintenance of ideal weight or weight reduction, adequate handling of sugars/carbohydrates, avoidance of falls and an acceptable response to the cold.  These are advantages that guarantee continued independence and optimal quality of life.  These are benefits that should motivate every adult over 50 to participate in this strategy. 

Progressive resistance training is part of 4-prong exercise program for the older adult

PRT is one part of a 4-prong exercise program validated to minimize age changes.  PRT is of high priority considering the plethora of positive outcomes for the older adult.  However, the three other components (aerobics, balance and stretch ) of the 4-prong exercise program provide different but equally important advantages and will be discussed in my next blog.

Resistance exercise with machines

PDF 1 (Resistance exercises with machines) describes evidenced-based PRT proposed by Law et al., (2016)**   It consists primarily of exercises using machines one would find in a fitness gym or YMCA.  There are three progressive levels, beginner, intermediate and advanced that progress the individual from 1 set of 12 repetitions to 3 sets of 10 repetition over a period of 32 weeks.  Machine-dependent exercises is probably the easiest way to initiate PRT but this approach does require a gym membership.  The main advantage is that experienced personnel are available to assist with the use of each machine.  To provide a level of familiarization, PDF 1 also contains videos that demonstrate the proper execution of each exercise with the particular machine. 

Resistance exercises with dumbbells

PDF  2 (Resistance exercises with dumbbells) follows the progression of strength training defined by Law et al., in PDF 1 but substitutes dumbbells (hand held weights).   The advantage of these exercises is that they can be done at home.  However, one must purchase a set of dumbbells.  I have added videos for all of these exercises since it is essential that they be performed exactly as described to gain the most benefit and avoid injury.

Alternative workouts

PDF 3 (Alternative workouts) list 7 different workouts ranging in time and difficulty, available on line that one may also follow and that can be performed at home.  Although none per se have been subjected to a clinical trial they contain exercises providing benefits comparable to those defined in PDF 1 and 2.  The key point to remember is that resistance exercise needs to be progressive.  Thus either increase in weight or resistance and/or number of repetitions is required to yield strength benefit.

*  Liu C-J, Latham NK.  Progressive resistance strength training for improving physical function in older adults.  Cochran Database Syst Rev: July 8 (3): CD002759, 2009.

** Law TD, Clark LA, Clark BC.  Resistance exercise to prevent and manage sarcopenia and dynapenia. Annu Rev Gerntol Geriatr 36: 205-228, 2016.

PDF-1-Resistance-exercise-with-machinesDownload
PDF-2-Resistance-exercise-with-dumbbellsDownload
PDF-3-Alternative-workoutsDownload

Insight 2: Skeletal muscles, aging and consequences

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Gradual loss of skeletal muscle mass and skeletal muscle strength is the most insidious and perilous age change of all

In my first blog, I explained that the trajectory of the aging process depends largely on an individual’s lifestyle choices.  It is, therefore, important that every older adult understand exactly what age changes can be expected and secondly, and most importantly, how to negate or minimize them.  This blog will describe one of the most troubling and debilitating effects of aging, loss of skeletal muscle mass (also referred to as muscle size) and loss of skeletal muscle strength.  I will follow this up with insight 3 (my next blog) on what to do about these changes.  Specifically, I will detail successful strategies of progressive resistance training plus consumption of quality protein.

Muscle mass and strength decline over time

It is well established that muscle mass and strength gradually decline over time.  A starting point, although variable and depending on the daily level of physical activity, is generally denoted at about 50-60 years of age but may start many years earlier.  Loss of muscle mass, termed sarcopenia, is about 1%/year whereas loss of muscle strength, designated dynapenia, is much greater, at about 3%/year.  Unfortunately, these changes go unnoticed especially in the case of declining muscle size since fat accumulation sneaks in to replaces muscle cells that either shrink or disappear.  This is illustrated in the MRI scans shown below.  Often muscle weakness is regrettably accepted as an inevitable and unalterable age change.

Just a brief note on the terms, sarcopenia and dynapenia.  A diagnosis of either sarcopenia (loss of muscle mass) or dynapenia (loss of muscle strength) indicates that a measureable quantity of decline in muscle structure and function has been determined.  Although not set in stone, there are defined numerical “cut-off” values (e.g. values for mass of arms/legs, grip strength, force of knee extension, speed of walking or rising from a chair)  associated with each term that have been established by professional medical research groups worldwide.  If a patient undergoes an assessment in which mass and strength are quantified and the numerical values fall below the established cut-off, the physician will make a diagnosis of either sarcopenia or dynapenia or both and propose appropriate therapy to prevent a worsening of these losses.  However, the goal for the older adult should be to continuously optimize muscle size and strength so that a designation of sarcopenia/dynapenia is never obtained or even considered.

Consequences of loss of muscle strength (dynapenia) – abundant, negative, and life-shortenin

Why be concerned about loss of muscle strength?  Because this change definitely leads to:

(1) increased physical disability; decreased quality of life,

(2) increased risk of falling,

(3) shorter lifespan. 

The most destructive change induced by dynapenia is the most obvious:  reduced leg, chest, back, shoulder and arm strength/power (speed) that slow and hinder performance in all daily activities from standing to walking to lifting to breathing.  As mobility and gait speed decline so does the total level of physical activity, further accelerating the decline in strength and power.  This inevitably leads to physical disabilities, loss of independence, and reduced quality of life.  Secondly, diminished skeletal muscle strength alters posture, a change which causes unsteady balance and an elevated risk of a fall.  Falls are menacing events with a high probability of a fracture,  hospitalization and lengthy recovery.  Additionally, weakened chest, back and shoulder muscles secondarily compromise the ability to augment the exchange of oxygen and carbon dioxide during stressful activities e.g. climbing stairs.  A reduction in gas exchange generally slows or halts the activity and reduces independence.  Dynapenia not only translates into poor physical performance and physical disabilities but, sadly, it has been statistically associated with increased mortality (premature death).

Consequences of loss of muscle mass (sarcopenia)

Why be concerned about loss of muscle mass?  Because this change definitely leads to:  

(1) weight gain,  

(2) elevated risk for Type 2 Diabetes 

(3) cold intolerance.

Weight gain occurs because skeletal muscles burn up a lot of calories just for maintenance.  The totality of muscle mass is huge and exceeds that of all other tissues combined.  Less muscle tissue means less calories consumed by muscles and more calories converted to fat storage and hence an associated weight gain.  In addition to the increased poundage, accumulated fat in the older adult locates, for as yet poorly understood reasons, to sites (abdomen or waist area; on top of major organs such as the heart) that encourage chronic low level inflammation, a major factor contributing to tissue damage.  Clearly an unwanted effect.  Secondly, muscles are one of the prime tissue targets that readily acquire ingested sugars, a process facilitated by insulin.  Less muscle, less uptake of sugar by this tissue and more sugar remaining to circulate.  Persistently elevated sugar levels augment the risk for Type 2 Diabetes and furthermore, promote spontaneous oxidative damage (a type of tissue damage) throughout the body, another unwanted effect that accelerates aging.  Finally, an often overlooked function of skeletal muscles is heat production in the form of shivering at low ambient temperatures.  Less muscle mass means less vigorous shivering and reduction in expected warmth.  This is experienced as cold intolerance which means that at low ambient temperatures, one needs to put on more outerwear to keep warm.  This compensates for the loss of extra heat normally supplied by customary muscle mass of young adulthood.

Pictures depict loss of muscle mass 

The first illustrates the extent of muscle loss that typifies sarcopenia.  The second picture show actual data of  the cross-section of the thigh region obtained from MRI scans of 3 volunteers:  a 40 year old triathlete, a 74 year old sedentary man and a 70 year old triathete.  Triathlete are athletes who compete in the triathlon (competitive biking, running, swimming events).  In each cross-section of the thigh muscle, the small white center circle is the bone.  It is surrounded by dark material (muscle) and defined by an outer sheath.  Thigh scans of the 40 and 70 year old triathlete are remarkably similar.  However, major changes are observed with the center photo of a 74 year old sedentary man.  Muscle tissue has disappeared and the space formerly occupied by muscle cells has been replaced with adipose tissue, another name for fat.  This sobering image emphasizes the actual extent to which skeletal muscle can disappear.  Regrettably, as serious as muscle mass disappearance may appear, the associated reduction in strength is several fold greater than the observed loss of mass!

Significant loss of muscle mass

It seems reasonable to assume that if one understands the severe consequences of aging in skeletal muscle, then what must follow is both an interest and a motivation to avoid them with proven interventions.  My next blog (Insight 3) will discuss strategies that achieve this goal.