The Cheat Sheet on Aging, Part II

The Bladder

The muscles of the aging bladder are more likely to spasm (called “overactive bladder”), and this is the most common reason for unintentional leakage of urine in men and women. When the bladder muscle spasms, you get the sudden urge to rush to the bathroom to urinate.
The best treatment for an overactive bladder is bladder training. When the sudden urge to urinate comes on, try the “hold and squeeze” technique to keep the urine in the bladder. Then, walk to the nearest bathroom. Keeping a diary to record when you are urinating throughout the day is also helpful. You will be able to see how long you can go between bathroom breaks and if there are any triggers for you.
Older women are more likely to develop bladder infection for many reasons. The female urethra shortens, making it easier for bacteria to invade. Loss of estrogen after menopause makes the skin of the urethra and vagina drier and more likely to crack and fissure.
Older people often have to get up at least once during the night to urinate. As we age, our bodies make less of an anti-diuretic hormone so it becomes more difficult to make it through the night without urinating. Most older men have an enlarged prostate and this condition can also cause frequent nighttime urination.
Prostate enlargement occurs in 60% of men at age 60 and in 80% of men at age 80. In some men, this condition can cause symptoms such as frequent urination, getting up at night to urinate, leaking urine and difficulty getting a steady stream of urine out.

The Lungs

With age, the lungs become stiffer and less elastic. On older person cannot forcefully exhale as much air in 1 second as a younger person can.
Overall, older people breath more quickly and with more shallow breaths than a younger person does.
Obstructive sleep apnea becomes much more common in the elderly and it is a common cause of daytime drowsiness.

The Kidneys

The mass of the kidneys decreases by 25-30% between age 30 and age 80. Fat and scar tissue replace some of the remaining kidney cells.
The kidneys are responsible for metabolizing drugs and filtering waste products out of the body. The filtering ability of the kidneys drops progressively with age and this decline accelerates after age 60.
With aging kidneys, many drugs are metabolized more slowly and stay in the bloodstream longer. Thus, many older people need to be given a lower dose of medication than a younger person would get.

The Rectum

The external anal sphincter, a mass of muscle 10 cm in length, holds the stool in the rectum until you want to go. Both sexes are affected by decreased resting pressure in the anal sphincter with age. This means that the muscle is less able to generate enough pressure to prevent the stool from leaking out.
Fecal incontinence, or leakage of stool, is more common in older women. One reason for this is that females are more likely to have suffered from complications of the vaginal birthing process, including pudendal nerve injury and stretching of the pelvic muscles. Nerve and muscle injury is even more likely to occur when episiotomy is performed or when forceps are used to assist in vaginal delivery.

Bone, Tendon and Muscle

Muscle loss begins at approximately age 40 in both men and women. We lose about 8% of our total body muscle mass every decade until age 70. At this point the progressive loss of muscle mass accelerates to 15% per decade.
Resistance training is the most effective way to prevent the progressive loss of muscle mass and strength that occurs with aging (a process known as sarcopenia).
As we get older the rate of muscle breakdown begins to exceed the rate of muscle formation. Testosterone levels drop which leads to lower muscle mass and bone strength. Fat cells begin to infiltrate the abdominal cavity and surround organs such as muscle and liver.
To make things worse, older individuals develop anabolic resistance, meaning that the body is less able to respond to existing hormonal signals to build muscle.
There are two different types of skeletal muscle: slow twitch muscle fibers which are best suited to endurance activities and fast twitch muscle fibers which enable us to perform speed and power exercises. As we age, we lose more fast twitch muscle fibers which decreases our speed, explosive strength and power.
Proteins are the building blocks of muscle and the body must have an adequate supply of protein in the diet to make new muscle. Because our bodies become less efficient at making protein as we age, research suggests that older individuals may benefit from a higher recommended daily allowance of protein- one gram of protein per kilogram of body weight every day (1 gm/kg/day). The current recommended dietary allowance (RDA) for protein intake for all adults is 0.8 g/kg/day.
Muscle mass is lost in the legs before the arms. Similarly, leg strength is lost at a faster rate than arm strength.
During periods of complete inactivity (during a prolonged hospitalization for example), muscle strength declines by 1-3% per day and by 10-15% per week, until it plateaus at approximately 25-40% of the baseline strength.
Pain in one joint can often be explained by a biomechanical problem elsewhere in the body. No area of the body acts in isolation. Instead, the body should be visualized as a kinetic chain of multiple joints linked together by muscles, ligaments and bones.
Chronic injury involves many interrelated factors: tissue trauma, inflammation, muscle spasm, adhesions or scarring in the soft tissue, muscle imbalance and impaired brain control of muscle.
Especially with our sedentary lifestyle, many people are prone to certain joint injuries because of poor posture and lack of balance between different muscle groups of the body. The main factors causing these imbalances include habitual movement patterns and altered movement patterns from prior injuries or surgeries.
Many individuals develop rounded shoulders and a forward head posture after decades of looking at screens. This faulty posture causes an imbalance between the weak and underused muscles of the upper/mid back (the rhomboids, lower trapezius, teres minor, infraspinatous, deep cervical flexors) and the overused, dominant muscles of the upper chest and neck (pectoralis, upper trapezius, sternocleidomastoid and scalenes).
The rounded shoulder posture described above can lead to chronic shoulder pain, neck pain and/or headaches.
By age 70, your body is the cumulative product of everything you have done and experienced. Staying physically active is critical for maintaining quality of life.
To improve balance and stability while walking, an older person’s stride length is shortened and more time is spent with both feet in contact with the ground. Thus, walking is slower. Arthritis in the hips and knees often leads to a stooped posture.
Tendons, made of a protein called collagen, connect muscle to bone and help transmit force. The load capacity of tendons decreases with age and tendon injury becomes more common. Tendon injuries heal slowly because they do not have a good blood supply (as compared to muscle).
Overuse injuries most commonly affect the tendons and are often related to repetitive mechanical load, poor footwear, muscle weakness/imbalance and poor flexibility.
Aging increases the probability of fracture in men and women. Once fracture has occurred, it heals more slowly in older people.
Overall, bone mass declines by approximately 0.5% per year in healthy older people. Women are even more affected because of the steep drop in estrogen that occurs during menopause.
Often seen in older women, osteoporosis is a condition resulting in decreased bone strength and increased risk of fracture, especially in the spine and hip.
This type of fracture, called a fragility fracture, affects as many as 1 in 3 women and 1 in 12 men during their lifetime.

General Concepts

Non-renewable structures in the body will inevitably degrade and fail over time. Some of these structures include: brain neurons, heart muscle cells, the major arteries, the lens and retina of the eye, sound sensitive ear structures, kidney filtration structures (glomeruli), bone joints and adult teeth.
Individuals over age 30 tend to show a progressive decrease in fat-free mass (FFM) and an increase in fat mass. Fat mass reaches its peak in the sixties and then slowly declines. Some studies show an accelerated loss of FFM in women after they reach age 60.
In older people, fat tends to accumulate in and around organs in the abdominal cavity. This type of abdominal fat is especially dangerous because it increases inflammation in the body and increases the risk of developing diabetes.
Aging affects circadian rhythms of body temperature, sleep and hormone production. Elders experience a phase advance, meaning that they will typically fall asleep 1 to 2 hours earlier than their younger counterparts.
Hormone production and release into the bloodstream is blunted in the older body. Lower levels of hormones such as melatonin circulate in the blood, contributing to insomnia in many older people.
One of the most profound changes in the aging body is the decreased effectiveness of the immune system. This system is responsible for fighting infection and cancer. The result of an impaired immune system is increased vulnerability to infections, cancer and autoimmune diseases such as rheumatoid arthritis, hypothyroidism and multiple sclerosis.
A weakened immune system is less able to produce a fever to fight infection– fever is absent or blunted in 20 to 30% of older individuals, making it more difficult to recognize when a bladder infection or pneumonia is present. When infected, older individuals often have atypical symptoms such as confusion, anorexia, increased falls and generalized weakness.
Your blood production system is located in tissues such as the bone marrow and spleen. Specialized stem cells in the bone marrow produce red blood cells, which carry oxygen to your body, and white blood cells, which defend your body against infection and malignancy.
With age, bone marrow mass decreases and fat cells infiltrate so you are less able to produce white and red blood cells when your body is stressed by illness or infection. This explains why older individuals do not respond as quickly to environmental stressors such as low oxygen levels in the atmosphere. The older person cannot increase the production of oxygen-carrying red blood cells as quickly as a younger person can.
Some aspects of the blood production system are preserved in old age: the lifespan of red blood cells, the overall blood volume and the total number of circulating white blood cells remains the same. Unfortunately, these white blood cells do not work as well as younger ones.
The blood of an older person clots more easily because platelets become “stickier” and the number of clot-forming proteins in the blood increases. Thus, an older person is more likely to form blood clots in the leg veins (deep vein thrombosis) and in the vessels of the lungs (pulmonary embolism)- even if she is otherwise healthy.
The average age at menopause is 51 years and the menopausal transition typically starts several years before this. During this time, menstrual bleeding becomes more irregular.
Many women experience hot flashes during the menopausal transition. The frequency and severity of hot flashes improves within a few months in 30-50% of women and resolves in 85-90% of women within 4 to 5 years.
A significant minority of women (10-15%) experience hot flashes for more than 5 years. Overall, African American women experience the highest frequency and longest duration of hot flashes.
Long term studies of twins suggest that approximately 25% of longevity is genetic.
The molecular basis of aging is currently a hot area of research. It is now believed that aging is due to the failure of our own DNA repair systems.

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References

Clark, M., Lucett, S., Sutton, B. G., & National Academy of Sports Medicine. (2014). NASM essentials of corrective exercise training. Burlington, MA : Jones & Bartlett Learning.

Fillit, H., Rockwood, K., & Young, J. B. (2016). Brocklehurst’s Textbook of Geriatric Medicine and Gerontology. Berlin: Elsevier.

O’Young, B. J. (2008). Physical medicine and rehabilitation secrets. Philadelphia: Mosby/Elsevier.