During the last decades of life, time will start to take its toll on our bodies, and things just won’t function like they used to. Reduced strength, mobility, and cognition is the inevitable fate that many of us must acquiesce to, but the degree to which we experience these can vary depending on the choices we make now and later. Much like the longevity of a car is dependent upon routine oil changes, maintenance check-ups, and tire rotations, the human body demands routine exercise, cognitive activities, and healthy choices. If your goal is to become a centenarian and have a high quality of life to the end, then these changes need to start in young to middle adulthood.

Previous chapters point to high BMI’s being strongly associated with increased risk of mortality, thus adopting a healthy lifestyle to maintain a healthy weight and lean body mass is the obvious goal. You already learned that obesity and developing chronic diseases will accelerate aging. During this chapter you will also learn that obesity can contribute to early frailty.

However, you may be surprised to know that our trusty BMI that works well as an easy predictor of mortality in many adults becomes nearly obsolete, as our aging bodies start to relinquish the muscle, bone, and fat mass that’s carried us to old age as if saying, “I’ve had enough!”

In this chapter we hope to draw attention to the growing ambiguity of BMI with age, talk about frailty as a major driver of low life quality in high age, and provide strategies to keep us healthy and functioning as long as possible.

The BMI Is Not a Good Predictor for Mortality: Sudden Drop in Weight Is

You are probably familiar with the black line in the graph above from other nutrition courses. This black line informs how most of us see the connection between BMI and the risk for premature death. According to the black line the ideal BMI seems to be anywhere between a BMI of 22 and 25. Once the BMI is outside of this “ideal” BMI the risk of dying prematurely increases in a U-shaped way. As always keep in mind that there are population groups the BMI does not apply to such as very short, very tall, and very muscular adults.

During the last decade this understanding changed. For one, scientists looked at the data that led to the black U-shape mortality curve and realized that smoothing of the data was hasty. A renewed analysis indicated that for the entire normal and overweight BMI range mortality is not necessarily increased. Chronic diseases—morbidity—is still more likely in the overweight category, but a healthy lifestyle and plenty of physical activity and exercise can go a long way.

Once we get into the obesity or underweight BMI range the risk for premature death increases exponentially.

In addition part of our “overweight” population can be considered metabolically healthy, meaning that they present no signs of high blood pressure, elevated blood lipids, and insulin resistance while some people in the normal weight category carry a lot of adipose tissue inside the body cavity and show signs of decreased metabolic health.

A BMI for young and middle adulthood is a good predictor for possibly developing chronic diseases if somebody is obese. Practically this means though that a high or low BMI should always lead to further discussion about lifestyle habits and not to the recommendation “to lose some weight’.

After 65 Years of Age the BMI Should Be Used to Monitor Weight Development

Once the scientists started looking only at the data set for  populations over 65 years the results became surprising. A BMI of 28-30 has the lowest mortality risk? If you’re doing double and triple takes at the BMI scale, you’re not alone. Another interesting aspect of this analysis are the thin lines below and above the average hazard for death. The higher the weight the wider the range. This means that some obese seniors are not at an increased risk of dying early due to their high weight. Others have a much higher risk of dying. Confusing? You are not alone.

There are two key facts that explain these findings. The changing body composition of seniors and the fact that adipose tissue has a purpose as an energy reserve.

Age-Related Body Composition Changes and the BMI

You already met this issue during the pregnancy chapter. Pregnant women see a physiological shift in body composition—more fat mass, more body water—and this makes the BMI obsolete. Seniors also have a physiological shift to more fat mass, especially the shift from subcutaneous to central fat stores, specifically to visceral stores. Bone mass declines and after age 75 the lean mass tends to decline as well.

This change in body composition and makes the BMI harder to interpret.

In senior age a BMI in the normal range is more often associated with a person that has underlying diseases and is frail and has a high risk for death.

Underweight has definitively an increased risk for death because a BMI under 18.5 is related to underlying diseases, frailty and a lack of reserve.

Obesity over a BMI of 35 is also connected to a higher risk. The reason is not so much related to the BMI, but to the chronic diseases that develop in the high BMI range. I fact 90 % of seniors with a BMI over 35 are metabolically unhealthy and they tend to be frail as well.

The remaining BMI range between higher normal weight category and class 1 obesity is not automatically connected to a higher risk for mortality. Around 30 % of seniors in this BMI category are metabolically healthy. Monitoring of the BMI, lifestyle, and symptoms of chronic diseases over time is important.

Energy Reserves Are Important in Old Age

From the previous chapter you know that muscle and organ function declines with age, but especially in high age. In addition, the risk for chronic diseases and infectious diseases (flu, Covid-19) increases.

You know that it becomes progressively harder with age to bounce back from diseases, stress or even exercise.  Now imagine a senior that is very thin before they contract the flu or need surgery. In both cases the senior will lose lean mass rapidly because of a reduction of physical activity. If said senior does not have any energy reserves the recovery becomes even harder. This seems to be the reason why a BMI in the upper overweight range is indicative of good nutrition, giving the senior more nutrients and energy reserves to recover.

Sudden Weight Loss Is the Strongest Predictor For Mortality

Sudden weight loss has been identified as one of the key predictors of mortality in older populations. Sudden weight loss is defined as losing 4-5% of original body weight within a year or losing 10% or more of normal body weight in 5-10 years.³

Often this body weight loss—keep in mind that we are talking of sudden weight loss at any weight—includes lean body mass. Loss of lean body mass increases the risk of becoming frail. Developing frailty at any BMI range can send seniors into a downward spiral.

The Development of Frailty Impacts Quality of Life And Longevity

What picture are you conjuring up when I talk about a frail person? Most likely you think of a very thin, delicate person that could be blow over by a strong wind. This is not necessarily the case. Frailty can come with thinness or obesity. The main descriptor is a person who has little reserve and strength at any weight. In fact, today we see early onset of frailty especially in obese people living a sedentary lifestyle especially if they have developed chronic diseases.

The driving force for frailty is sarcopenia independent of weight.

Risk Factors Factors For Developing Sarcopenia

[Text coming soon]

How to Diagnose Sarcopenia

For the longest time sarcopenia was defined as the loss of muscle mass due to inactivity or old age. Recent studies had a closer look and didn’t find a direct connection between low muscle mass, disability, and mortality. Instead, those newer studies found a connection to disability, morbidity, cognitive decline and lower survival times when physical performance and muscle strength were both impaired. This led to a new definition of sarcopenia.

Sarcopenia is defined as low muscle mass combined with either low muscle strength and or low physical performance.

The physiological research back this finding. Elderly people do not just lose muscle mass but also see an increase in ectopic fat. Ectopic fat infiltrates muscles fiber and reduces muscle functionality and strength. Low muscle strength and functionality  decrease physical performance.

In addition advanced aging impacts all cells in the body (see cellular aging). Mitochondrial dysfunction reduces the production of ATP.  Fatigue is increased. ER stress reduces the effectiveness of protein folding and cellular garbage increases since the removal system is also impaired.

Combined with a sedentary lifestyle muscle mass decreases rapidly and the remaining muscle fibers are less functional.

Increase in ectopic fat and mitochondrial dysfunction is not only a feature of old age but can also increases in obesity as early as middle adulthood. Obesity increases ectopic fat amounts and the development of chronic diseases are combined with mitochondrial dysfunction.

How can we tell if a person has developed sarcopenia?

Thus it becomes important to know the signs and get tested for developing sarcopenia. The European Working Group on Sarcopenia for Older People (EWGSOP) has developed standards for diagnostic testing across the three parameters of sarcopenia which is recommended for individuals aged 65 and older:

• Physical performance: This is usually the first test conducted and is done so by observing patient gait speed (walking speed). The standard for a normal gait speed is anything greater than 0.8 meters per second. The gait speed can be measure in a hallway and requires only a measuring tape and some masking tape to mark start and end points. The patient has 2 meters to accelerate, then walks between 4 and 10 meters at top speed. This stretch is timed and the gait speed calculated.
• Muscle Strength: This is tested through the use of a hand grip called a Dynamometer. Squeezing the grip will display the amount of strength in kilograms with the normal being about 28.0-44.0 kg and 15.0-27.0 for males and females respectively.
• Muscle Mass: This is usually the last test conducted which is most commonly done through dual-energy X-ray absorptiometry (DXA). Among other mass tests, it’s the most accurate at estimating the proportion of lean mass, fat, and bone density. The skeletal mass is divided by the individuals height to determine the amount of mass and cut-offs are based on individual factors

The final diagnoses of sarcopenia is done through a combination of these tests.

Prevention and Treatment of Sarcopenia

The best way of course to prevent sarcopenia is a heaving a healthy lifestyle in young and middle adulthood. It is similar to osteoporosis. Developing optimal bone density will give you a reserve when bone loss naturally occurs during aging. Developing a healthy level of lean body mass and muscular strength will give you a reserve during age-related LBM decline.

Does that mean that nothing can be done if sarcopenia develops with age? Here the research is promising. Short-term exercise interventions including resistance training (about 5 months) have been effective in increasing quality of life and independence. Dietary interventions such as protein and vitamin D supplementation are researched as well, but with unclear results.

Sarcopenia Is the Driving Factor For Frailty

Late diagnoses and failure to effectively treat sarcopenia will inevitably lead to a state of frailty. When thinking of frailty, the word “fragile” comes to mind. If not handled with care, fragile objects can break/fall apart. While I hope your not picking up elderly people and dropping them, someone experiencing frailty must be handled and treated with the utmost care, otherwise a cascading decline across multiple dimensions of health will  begin.

Sarcopenia leads first to a functional decline. Once people cross a certain sarcopenia threshold poor strength and physical tiredness leads to walking and balancing problems. Developing those problems people with sarcopenia go less out, sit more at home, and start limiting physical activity entirely. Frailty sets in.

Live completely changes from one of activity and social interaction to spending more time alone. Frail people tend to feel down, anxious and depressed. Mitochondrial dysfunction also affects the brain and problems with coping, learning and making decisions develop.

The social isolation due to the inability to move and the avoidance of challenging situations will lead to social decline.

Those three areas of frailty are not isolated from each other. Social isolation leads to less stimulation which hastens the cognitive decline. Feeling bored and alone increase depression symptoms. Depression and social isolation leads to less movement because there is no reason to challenge oneself.

You can clearly see how sarcopenia, once it results in frailty, can start a vicious downward spiral.

The Development and Progression of Frailty is a Dynamic Process

Frailty is an age-related clinical condition that is connected with a decline in functioning across several physiological systems with an increased vulnerability to stressors.

“The interconnected nature of frailty can lead to substantial declines across multiple forms of well-being. When I worked in a retirement home, multiple forms of frailty could be visibly seen in the residents. From a displeased scowl directed at the nights dinner to a resident socially isolating themselves in the corner of the dining room, it was easy to see these forms of frailty unfold.

However, there were times when the socially isolated resident would meander over to a small table of three and engaged in small talk. I even walked into the four of them blissfully devouring dairy queen together, a interaction so humbling that branding the resident as isolated would have never have come to mind.

This example actually represents the dynamic nature of frailty. It’s not a simple linear decline towards dysfunctionality, but rather a wellbeing water slide with twists and turns that make some days great and others not so much.

What separates the bad from the good days is usually the amount of stressors someone with frailty faces. Being in the declined state that they are, even the smallest forms of stress can have a huge impact. Waking up to find that the cereal, a routine order for one of my residents, was accidentally misplaced with a fruit bowl was too much for this resident to handle and it sent them into spiraling rage for the next few days.

This dynamic, if not handled with care, will eventually lead to a dangerous state of frailty that contributes to health risks. Those most immediate risks include falls, delirium, and fluctuating disability. This inevitably leads to increases healthcare costs and can force some families to make the decision to admit an elderly relative to long-term care facilities or hospitals.

“~Eric

Frailty is not a straight line to death but the condition is an oscillating up and down until frailty spirals out of control and hastens death. Frailty is not equally distributed in our society. Women are more affected than men and the more financial resources a person has the less the aging process is connected with frailty. People with a low income cannot afford to live in an environment with ample social stimulation, a variety of exercise or eating a healthy diet. Once frail seniors need to give up their home environment and live in a care facility money determines their ability to live in an environment that offers cognitive and social stimulation as well as exercise classes.

Progressing Frailty Is Connected to An Array Of Geriatric Symptoms

When sarcopenia reaches a threshold the first symptoms of frailty show. The first symptoms is usually undue exhaustion. Daily living starts to cause excessive fatigue. In consequence the person slows down and then lowers physical activity entirely. The reduced physical activity leads to more muscle loss and general weakness sets in.

Once frailty takes a hold of the person and progresses other feared geriatric symptoms can be detected. These include cognitive decline, falls due to strength and balance problems. Broken bones and injuries reduce physical activity further and lead to an accelerated cognitive decline. Once the frail person spends most of the day in bed pressure ulcers and delirium are feared.

In clinical settings the clinical frailty scale to the right is used to identify the degree of frailty and start appropriate interventions.

Keep in mind though that two frail people can cope very differently and therefore the trajectory of frailty is very individual. A person that is still socially connected with plenty of family and friend visits will cope with a setback for example from a fall easier and recuperate. Or not, if the frail person is depressed or more anxious by nature. The living environment plays a huge role here. Meaningful social connections, cognitive stimulation and continued exercising will keep the person on a much slower trajectory.

Frailty Prevention And Intervention Strategies Include Diet And Exercise 

Frailty can be present in normal weight, overweight or obesity, but sudden weight loss is the best predictor for sarcopenia, developing frailty and ultimately mortality. Spotting the sudden weight loss and starting lifestyle interventions can prolong life and increase quality of life.

The available knowledge for the effectiveness of nutrition intervention is limited and no perfect blueprint has been found. The goals are to reduce severe obesity to allow for easier physical activity and reduce inflammation. Reduction of inflammation is also supported by eating a plant-heavy diet rich in anti-oxidants and flavonoids. At the moment the recommended diet is a Mediterranean style diet because studies have demonstrated a positive impact on inflammation, chronic diseases and cognition. Not all elderly people will accept a Mediterranean diet. Similar culturally appropriate diet such as the DASH diet are good choices as well.

The main goal of the dietary intervention is to prevent sudden weight loss especially from muscle mass. The research has focused heavily on increased protein intake, vitamin D, omega-3 fatty acids, and antioxidant supplementation as an intervention strategy as well. But again, clinical trials have shown mixed results, nonetheless, the intake for these nutrients should be adequate to support maintenance of muscle mass and build reserves for health set-backs.

As always, prevention is better than intervention. A healthy plant-heavy, nutrient diet will be the first important preventative step to avoid sarcopenia and frailty. A focus on protein intake is more important once people reach old age since most Americans have a more than adequate protein intake.

Starting an Exercise Regime Improves Quality of Life Tremendously

A gym membership for frail elderly people? Maybe not to your favorite gym, but starting an appropriate exercise program is essential for increasing strength and reversing frailty. Studies evaluating exercise programs for frail people have shown to be very successful in reversing frailty and increasing independence.

The program should start out with light resistance training, balance, and flexibility training. The aim is to improve muscle mass, increase independence and balance. This will allow more independence completing daily chores such as dressing and moving around and reduce the risk for falls.

Once initial improvement is reached the exercise program should be ongoing and address the three key areas of exercise programming.

• Resistance: Resistance training should be light and progressive, and targets all major muscle groups. It should be done 2-3 times per week. Increased muscle strength will not only help with everyday mobility, but also improve balance.
• Flexibility & Balance: flexibility training should be reinforced everyday through passive stretching while balance training should be done 2-3 times per week.
• Aerobic: Once strength has returned moderate aerobic activities such as aerobic exercise classes, walking, dancing should start. Intensity should be enough to elevate the heart rate but not lead to total exhaustion. Doing so for 20-30 minutes, 3 times per week is recommended.

Unlike diet interventions, exercise intervention programs have shown impressive results  treating sarcopenia and ultimately frailty. Resistance training has been clearly associated with improved speed gait and increased lean muscle mass.