The Biology of Aging: Understanding the Cellular Mechanisms of Senescence 

During infancy and throughout adolescence, most of us enjoy relatively good health, from our blemish-free skin to our well-functioning internal organs. In this period of our lives, cell regeneration occurs effortlessly. When cells become aged or damaged, our bodies naturally initiate the process of cell division and replication to ensure ongoing vitality and well-being. 

As we age, our cells begin to reach the maximum number of times they can divide. When this happens and they can no longer create new cells, they reach a state of senescence

But what is senescence, exactly? 

Today, we’re exploring the biology of aging and its connection to senescence to gain a better understanding of how and why our bodies age. 

Senescence and Aging 

Senescence and aging hold very similar meanings. The term ‘aging’ encompasses the overall process of becoming older, including the physical and mental decline in our health. Senescence, however, refers to the aging process on a cellular level, focusing on the microscopic changes that occur within our cells throughout our lifetime. 

As we age, more cells lose the ability to divide, and the number of senescent cells in our bodies increases. The accumulation of these cells often leaves lasting impacts on the overall aging process, from the appearance of wrinkles to the emergence of age-related health conditions. 

What Causes Us to Age? 

In 1900, the average life expectancy of a newborn was 32 years. During that time, most people didn’t live long enough to experience deaths related to the effects of senescence, such as cancer or heart disease. Rather, they died prematurely due to outside influences, like infectious diseases and parasites. 

Fast forward to today, when the average life expectancy has increased to 76 years. Now, most people 50 and older begin to notice several causes of aging, courtesy of senescence. But what causes senescence to occur? 

Below are a few of the factors that influence our cells to become senescent: 

Telomere Shortening 

Telomeres are repeated DNA sequences that appear at the end of our chromosomes. They act as a biological clock for each cell, counting the number of times a cell has divided. 

Each time a cell undergoes division to create a new cell, its telomere shortens. Eventually, the chromosome’s telomere becomes too short to divide further, which triggers the cell into a state of senescence. 

Oxidative Damage 

Everyday functions, like breathing and moving, create highly unstable and reactive molecules called free radicals in our bodies. Fortunately, our systems use antioxidants to neutralize them, preventing them from causing us harm. 

However, external factors such as UV radiation and pollution can create an excess of free radicals inside of us, disrupting the delicate balance between free radicals and antioxidants. This imbalance, known as oxidative stress, can cause damage to molecules in our cells and DNA, shorten telomeres and activate certain pathways in the cell that lead to senescence. 

Physical Effects of Senescence in the Form of Aging 

As you age, more cells reach senescence, increasing the likelihood of experiencing several aspects of aging, including: 

Fortunately, lifestyle factors do play a role in the rate at which you age! You may be able to slow down the process of cellular senescence by incorporating the following practices into your daily routine: 

  • Eating a balanced diet rich in healthy fats, protein and complex carbohydrates. 
  • Engaging in regular exercise. 
  • Receiving an adequate amount of sleep. 
  • Wearing sunscreen to limit your exposure to potentially harmful UV rays. 
  • Stimulating your brain with activities, such as reading, puzzles and keeping in touch with family and friends. 

Begin Your Career in Aging With a Graduate Credential From UF 

Over the past hundred years, the average human lifespan has more than doubled, highlighting the growing demand for professionals in the field of aging. Gerontology, the study of aging, forms the foundation of this discipline, focusing primarily on older adults. Within this field, you can explore many aspects of aging, including physiological changes and the healthcare needs of older populations and strategies to enhance their quality of life. 

The University of Florida proudly offers several entirely online graduate programs in the field of aging, including: 

  • Master’s Degree in Gerontology 
    This 30-credit online program is ideal for those interested in pursuing an advanced career in the realm of geriatric care. 
  • Master’s Degree in Medical Physiology and Aging 
    If you’re interested in blending the knowledge and skills from two of our online programs, look no further. This unique online graduate degree combines the curriculum from our master’s degree in gerontology and our medical physiology graduate certificate, providing a well-rounded foundation of knowledge in multiple areas. 
  • Graduate Certificate in Aging and Geriatric Practice 
    Our 15-credit graduate certificate provides solid foundational skills in aging, enhancing your resume and giving you a competitive edge when applying to medical school or other health-profession schools. 

With competitive tuition prices, year-round start dates and asynchronous courses that make it easy to complete your coursework on your schedule, what’s stopping you from taking the first step toward a career in the field of aging? Apply today! 

Sources: 
https://www.ncbi.nlm.nih.gov/books/NBK10041/
https://www.cancer.gov/publications/dictionaries/cancer-terms/def/senescence
https://www.merckmanuals.com/home/older-people%E2%80%99s-health-issues/the-aging-body/changes-in-the-body-with-aging
https://ourworldindata.org/life-expectancy
https://www.cdc.gov/nchs/pressroom/nchs_press_releases/2022/20220831.htm
https://www.frontiersin.org/articles/10.3389/fnagi.2022.827900/full
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5748990/
https://www.frontiersin.org/articles/10.3389/fnagi.2023.1281581/full
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8657738/