How Does Alzheimer's Affect the Body's Systems?

How Does Alzheimer’s Affect The Body’s Systems?

Alzheimer’s disease is more commonly known to affect cognitive function, but it can also have an impact on other bodily systems as well. While it is a devastating disease, it’s important to understand what it is and its effect on the body. We will explore what body systems are affected by Alzheimer’s as well as the organs affected by Alzheimer’s disease.

What Is Alzheimer’s?

Alzheimer’s is a type of dementia that occurs when nerve cells in the brain die. It can lead to impaired memory, thinking and behavior as well as confusion. Symptoms continue to get worse and may grow severe enough to interfere with daily tasks. Everyday activities such as talking, eating, walking, and using the bathroom can become increasingly difficult to do on your own.

It is named after the German physician Dr. Alois Alzheimer who first discovered this disease in 1906.

It accounts for roughly 60-80% of dementia cases. Dementia is a general term to classify a decline in mental ability that is severe enough to interfere with daily life. Alzheimer’s is a specific disease which is caused by complex brain changes following cell damage.

Symptoms And Possible Causes

One of the most common early symptoms is difficulty remembering new information because the disease typically impacts that part of the brain first. As Alzheimer’s advances, symptoms get worse and can eventually lead to difficulty with speaking, swallowing and walking. Below are some of the most common symptoms:

  • Confusion
  • Problems with memory and thinking
  • Restlessness
  • Personality changes
  • Problems with judgement
  • Trouble communication, such as not making sense when talking
  • Problems following directions
  • Problems with spatial awareness, meaning not knowing how objects around you relate to you
  • Lack of interest or concern with other people
  • Forgetting who people are, including children and spouse
  • Misplacing things
  • Trouble doing familiar tasks

It is not a normal part of aging. The greatest risk factor is increasing age, with the majority of people who have it being age 65 and older. But there are about 200,000 Americans under the age of 65 who have it. It is most often caused by:

  • Age and family history
  • Certain genes
  • Abnormal protein deposits in the brain
  • Environmental factors
  • Problems with the immune system

Lifestyle factors linked to heart disease may also increase your risk of developing Alzheimer’s. Factors include smoking, alcohol, diabetes, and high blood pressure (hypertension). Physical inactivity (sedentary lifestyle) and a high body mass index (BMI) may also contribute to an elevated risk of developing the disease. While all of these listed factors play a role in Alzheimer’s risk, age remains the highest risk.

How Is Alzheimer’s Diagnosed 

It is often diagnosed by a healthcare provider ruling out other conditions first. A thorough exam of the nervous system will be conducted. A doctor will also do a complete health history, a mental status test as well as lab work and possibly brain imaging tests like a CT or MRI.

The effect that Alzheimer’s has on each individual can differ. The pace of the disease may be slower for some and advance much more quickly for others. The average life expectancy for someone diagnosed with this disease typically ranges between 4 to 8 years after diagnosis. However, it has been reported that some individuals have lived much longer after diagnosis, up to 20 years.

There is unfortunately no cure, but there are treatments that can temporarily slow symptoms from worsening and improve quality of life for those who have it.

The Stages Of Alzheimer's And How The Disease Progresses


Alzheimer's disease begins to take hold long before any apparent and surfacing symptoms occur. This stage is referred to as preclinical Alzheimer's disease and is typically only identified in a research setting. Symptoms during this stage will not be noticeable to you or those around you. 

The preclinical stage of Alzheimer's can sometimes last anywhere from a few years to even decades. Although there won’t be noticeable changes on the surface, new imaging technologies are now able to identify protein deposits (amyloid-beta) that are a hallmark of the disease. Biomarkers and genetic testing are also beneficial for evaluating how at risk you may be of developing the disease. 

Mild Cognitive Impairment

In the mild cognitive impairment  (MCI) stage, the brain's memory and ability to think clearly will begin to change. The changes will be mild enough that they won’t be significant enough at this stage to disrupt relationships or work as of yet. MCI may cause memory lapses involving relatively easily recalled information such as appointments, conversations, and recent events. 

You may also find yourself experiencing difficulty judging the amount of time needed or steps required to complete tasks. Alzheimer’s will begin to increase the difficulty of making sound decisions. 

Not everyone who struggles with mild cognitive impairment has Alzheimer’s. MCI is usually diagnosed with a doctor’s professional judgment and an evaluation of the symptoms. These same procedures help doctors to determine if the patient’s MCI is due to Alzheimer’s or something else entirely. 

Mild Dementia

The mild dementia stage is when Alzheimer's is most often diagnosed. During this stage, it will be clear to family and doctors that a person is struggling with their memory and thinking skills, impacting their performance of daily functions and tasks. 

Recalling newly learned information can become increasingly difficult during this stage. People in this stage may ask the same question multiple times as they struggle to retain the information. They may also experience difficulty with problem-solving, more complex tasks, and making sound judgments. Lapses in judgment occur often in this stage, such as when making a financial decision. 

How does dementia affect the body? Individuals will also experience increasing difficulty with getting around, even in places that should be familiar to them. Misplacing items and difficulty with organizing and expressing their thoughts are also common. Some individuals may also experience personality changes, such as becoming withdrawn or subdued. Irritability, anger outbursts, and lack of motivation to complete tasks are also common during this stage. 

Moderate Dementia

During this stage, people with Alzheimer's grow increasingly confused and forgetful, requiring more assistance with self-care and daily tasks. Individuals may need help choosing the proper clothes for an occasion or the weather. Loss of control of their bladder and bowel movements may also occur. 

Greater memory loss, increasingly poor judgment, and deepening confusion are prevalent during this stage. Because of these difficulties, leaving anyone suffering at this stage alone is considered unsafe. Wandering is common as they possibly try to locate some person or place that feels more familiar to them. 

Significant personality and behavior changes often develop in this stage. It is not unusual for individuals in this stage to develop unfounded suspicions. They may also begin to hear or see things that are not really there. It is common for individuals also to grow restless and agitated, leading to aggressive physical behavior and outbursts. 

Severe Dementia

In this late stage of the disease, mental function will continue to decline. This mental decline will lead to a growing impact on the individual's physical capabilities and movements. In this stage, individuals typically require total assistance with functions such as bathing, dressing, eating, and using the bathroom. 

Individuals may also become unable to walk without assistance and unable to sit or hold one’s head up without assistance or support. Reflexes are abnormal, muscles become rigid, and eventually, the ability to swallow or control their bowel and bladder is lost, as well. 

Communication is increasingly challenging at this stage. Although words or phrases may be occasionally uttered, an individual may no longer be capable of speaking in a manner that makes sense. Coherent communication becomes much more difficult. 

How Does Alzheimer’s Affect The Digestive System?

Researchers have found a connection between the microorganisms in our gastrointestinal system to a variety of health conditions including Alzheimer’s disease, but exactly how does Alzheimer’s affect the digestive system? The intestinal flora can produce something called amyloid, which enters the blood circulation and crosses the blood-brain barrier to get into the brain. 

The accumulation of amyloid plaques between nerve cells (neurons) in the brain is one of the hallmarks of Alzheimer’s disease. There is also a component of bacterial cell membranes known as lipopolysaccharides that can get into the body’s bloodstream and activate inflammatory processes which contribute to Alzheimer’s.

The risk can be reduced by eating a plant-based diet rich in fruit and vegetables and high in fiber. The Mediterranean Diet is a popular one that has been shown to reduce Alzheimer’s disease risk. Black and green tea can also help support gut health.

How Does Alzheimer’s Affect The Respiratory System?

Breathing problems aren’t normal, but they are quite common in older people, especially those with Alzheimer’s disease, but how does Alzheimer’s affect the respiratory system? It can be caused by a number of conditions, including:

  • Asthma
  • Anxiety
  • Infections
  • Choking
  • Diet and exercise
  • Blood clot
  • Chronic obstructive pulmonary disease (COPD)
  • Heart failure

Breathing issues can be prevented by avoiding sudden temperature changes, air pollution, pollen, dust, cigarette smoke and chemical fragrances.

Doing breathing exercises can help get as much air in the lungs as possible. One way to do this is to sit up straight. Then breathe in through the nose, purse lips and then breathe out slowly. Try to breathe out twice as long as you breathed in.

How Does Alzheimer’s Affect The Nervous System?

The nervous system is the center of all mental activity including thought, learning and memory. It works with the endocrine system to regulate and maintain homeostasis in the body.

Alzheimer’s disease leads to issues in the nervous system including cognitive function such as problems with memory, thinking or behavior as well as confusion and judgement. People with Alzheimer’s may have trouble doing familiar tasks and often misplace things.

Alzheimer’s disease mostly affects the brain and nervous system progressively getting worse over time.

How Does Alzheimer’s Affect The Brain?

A healthy brain contains billions of neurons, which are specialized cells that process and transmit information between different parts of the brain to the muscles and organs of the body via electrical and chemical signals (2). Alzheimer’s disease disrupts this communication. This ultimately results in loss of function and cell death.

The brain typically shrinks to some degree as a person ages, but it doesn’t actually lose neurons in large numbers. In Alzheimer’s disease the damage is larger. Neurons stop functioning and lose connection with other neurons affecting communication.

It first starts with destroying neurons that are involved in memory and eventually affects areas in the brain responsible for language, reasoning and social behavior. Overtime, a person may lose his or her ability to live and function independently.

People with Alzheimer’s may also experience vascular problems that may lead to reduced blood flow and oxygen to the brain. This results in inflammation which adds further vascular problems.

How Does Alzheimer’s Affect You Physically?

Alzheimer’s doesn’t just affect a person mentally, it can also affect a person physically too. Some people may end up with physical problems before experiencing serious memory loss. It can affect the way a person walks and talks as well as the issues listed below (1):

  • Loss of balance
  • Loss of coordination
  • Stiff muscles
  • Shuffling or dragging feet when walking
  • Trouble standing
  • Trouble sitting in a chair
  • Weak muscles
  • Fatigue
  • Trouble with sleep
  • Trouble controlling your bladder or bowels
  • Uncontrollable twitches

As the disease progresses, your body will be at greater risk for additional health issues. As your immune system begins to fail, you may develop infections more easily. Injuries due to falls from a loss of balance are more likely to occur. Most people who live with Alzheimer’s die from infections like pneumonia, as well as heart attack and other life-threatening health problems.

Daily Life And Challenges Of Care

Oftentimes people with Alzheimer’s have trouble taking care of themselves, even basic necessities like washing their hair and their body, brushing their teeth and changing clothes become increasingly challenging.

Some people even have trouble chewing food and swallowing. This could lead to dehydration and malnourishment. 

The risk of choking or inhaling your food becomes greater as your ability to chew and swallow steadily lessens. Additionally, inhaling your food or drink by accident can lead to pneumonia. 

Pneumonia is reported as being a common cause of death for those living with Alzheimer's due to food or drink entering the lungs and developing an infection. Malnutrition and dehydration, as well as falls and other infections, are also common causes of death. 

As of 2019, Alzheimer’s was reported as the fifth leading cause of death for people over 65 in the US. Between the years 2000 and 20019, Alzheimer deaths doubled. Reportedly, more people died from the disease than from breast and prostate cancer combined.


  • Don Moxley - Director of Applied Science

    Don Moxley is the Director of Applied Science at Longevity Labs. Moxley draws upon his career as an athlete, a sports scientist, and an instructor to lead and educate on the science of autophagy and longevity.