Why do our bodies age?

Definition of Aging

• Aging is a complex process that involves intrinsic biological processes as well as interaction with environmental factors (e.g., sunlight, toxins, diet).

• There is no strict scientific definition, but it can be described as changes in the structure and function of molecules and cells within the body.

• These changes lead to declines in functionality and ultimately the failure of the organism.

Mechanisms of Aging

• Scientists have identified nine physiological traits central to aging, including:

  • Genetic Damage:

    • Accumulation of DNA lesions due to replication and environmental factors.

    • Mitochondria are vulnerable, as they produce ATP and regulate critical cell functions (like cell death).

  • Epigenetic Changes:

    • Certain genes are silenced in youth but become prominent with age, contributing to diseases like Alzheimer's.

Cellular Regeneration and Aging

• Telomeres:

  • The protective regions at the ends of chromosomes shorten with each replication cycle.

  • Shortened telomeres limit cellular replication, affecting the body's renewal capabilities.

• Cellular Senescence:

  • Cells can grow senescent, halting their cycle in response to risks (e.g., cancer), which increases with age.

  • This response limits the body's ability to regenerate tissues.

Impact of Aging on Stem Cells

• Stem cells, crucial for replenishing other cells, decrease in number and regenerative ability as we age.

• This decline impacts tissue renewal and maintenance of organ functions.

Decline in Cellular Functionality

• Aging leads to:

  • Impaired quality control of proteins, resulting in toxic accumulations.

  • Excessive metabolic activity, potentially dangerous for cells.

  • Slowed intercellular communication, detrimentally affecting overall body function.

Future Perspectives on Aging

• The understanding of aging is still evolving, raising questions about the roles of diet, exercise, and medicine in longevity.

• Potential future technologies (e.g., cell-repairing nanobots, gene therapy) might extend lifespan artificially.

• Philosophical questions arise: do we desire to live beyond current limits, inspired by records like Calment's?

Impact of Aging on Normal Body Systems

Aging affects the functionality of various body systems, leading to a range of changes that can impact overall health and quality of life.

1. Musculoskeletal System:

   • There is generally a decline in muscle mass and strength (sarcopenia) as well as bone density, increasing susceptibility to falls and fractures.

2. Cardiovascular System:

   • Blood vessels may lose elasticity, leading to higher blood pressure and a higher risk of cardiovascular diseases. Heart rate may also not respond as well to physical stress.

3. Respiratory System:

   • Lung capacity decreases, and breathing may become less efficient due to loss of elasticity in lung tissues and reduction in overall respiratory muscle strength.

4. Nervous System:

   • Cognitive functions may decline, potentially leading to memory loss, impaired processing speed, or conditions such as dementia. Neuronal plasticity also decreases.

5. Endocrine System:

   • Changes in hormone levels can affect metabolism, leading to increased fat accumulation and challenges in maintaining muscle mass.

6. Immune System:

   • Immune response becomes less robust, increasing vulnerability to infections and chronic illnesses. There is also a higher incidence of autoimmune disorders.

7. Gastrointestinal System:

   • Digestion slows down, leading to problems such as constipation and decreased absorption of nutrients, which can impact overall health and energy levels.

Impacts of Aging on Older People

• Older individuals may experience a combination of physical and cognitive impairments, which can affect their ability to perform daily activities.

• Chronic conditions such as arthritis, diabetes, and heart disease may become more prevalent, complicating their overall health.

• Psychological aspects such as depression or anxiety can also arise due to social isolation or loss of independence.

• Nutritional needs become critical, and older adults often need to adapt their diets to maintain adequate nutrition due to changes in metabolism and appetite.

Changes Nurses Might Expect to See in Older Patients

• Physical Changes: Reduced mobility (muscle weakness, stiffness), slower healing time, increased frequency of fatigue.

• Cognitive Changes: Short-term memory loss, confusion, difficulty focusing, or processing information.

• Emotional and Psychological Changes: Signs of depression or anxiety, changes in social engagement, and potential behavioral changes due to cognitive decline.

• Vital Signs: Variations in baseline blood pressure and heart rate, slower recovery from exertion, and potential for orthostatic hypotension.

• Nutrition and Hydration: Changes in appetite or dietary preferences seemingly impacting nutritional status, leading to weight loss or dehydration, which are common concerns in older adults.