The Comprehensive Guide to Primary Ageing and Secondary Ageing

As you set foot in your later decades, it’s normal to experience age-related changes like creaking joints and graying hair. These are hallmarks of primary ageing, a natural process that causes your body functions to slowly decline over time.

On the other hand, diseases like cancer and high blood pressure are not synonymous with primary ageing. Instead, they are considered part of the secondary ageing process. Still, the rising occurrence of such illnesses is a cause for concern. In fact, the World Health Organization has predicted that chronic illnesses would increase by 57% by 2020 (from 2001).

The good news though, is that most chronic illnesses associated with secondary ageing can be avoided by living healthily. Healthy lifestyle choices also help to lessen the impact of primary ageing to a certain extent. In this article, we will discuss what primary ageing and secondary ageing entail. We will also look at ways to promote healthy ageing so that you can enjoy a better quality of life in old age.

What Is Primary ageing and Secondary ageing?

Primary ageing, also known as normal ageing, refers to the maximum lifespan of a species. This ageing process is unaffected by lifestyle factors such as stress, smoking, and diet. For humans, our maximum lifespan is 125 years.

Primary ageing can also be linked to chronological age — basically your age in calendar years. Just like primary ageing, your chronological age is also unaffected by external factors.

Secondary ageing refers to the life expectancy of a population, or the amount of time an individual is expected to live. It's affected by genetics and environmental factors. The life expectancy of an average American is 79 years old.

Another way to look at secondary ageing is through biological age, also referred to as your perceived age. Your biological age may be lower than your chronological age. In other words, you look younger and healthier than peers of the same age.

To put everything into context, think of primary ageing as the maximum number of years you could live while secondary ageing represents the risk factors that prevent you from reaching the maximum lifespan. These risk factors are usually in the form of diseases or disabilities that are a result of an unhealthy lifestyle.

The Link Between Senescence, Primary ageing, and Secondary ageing

To understand the differences between primary ageing and secondary ageing, we first need to look at a process called senescence.

What Is Senescence?

A 2002 study by the University of California, Berkeley explained that senescence is the process in which your cells stop dividing over time. Based on the Hayflick limit, the approximate number of times a cell can divide is 50 to 70. Once that limit is reached, the cell becomes senescent and remains metabolically active. But what happens to it?

According to a 2019 study in the Biochemia Medica Journal, senescent cells are eliminated in a process called senescent cell clearance by senescence-associated secretory phenotype (SASP) factors. This elimination process stops taking place with age, and these cells accumulate. The result is health changes like ageing and chronic illnesses.

A 2016 study published in the Journal of Nature Medicine details the three ways in which senescence can take place:

• Senescence due to normal ageing
• Senescence due to diseases
• Senescence due to medical treatments

This shows that both primary ageing and secondary ageing are associated with senescence.

Primary ageing and Senescence

The main cause of primary ageing is accumulated "wear-and-tear" at the cellular level. This damage is triggered by cellular stressors like free radicals, telomere shortening, and DNA damage. As such, your cells and tissues degenerate over time, leading to slower physical movements and brain activity.

Secondary ageing and Senescence

On the other hand, senescence in secondary ageing is caused by diseases and medical treatments.

Disease-related senescence is triggered by chronic diseases that take place as a result of environmental factors and unhealthy habits. For instance, smoking leads to long-term oxidative stress that increases cellular damage in the lungs. In response, there is now a greater number of senescent cells. This then results in lung disease.

Therapy-induced senescence is normally experienced during medical treatments like chemotherapy. Such treatments further intensify cellular damage beyond the normal levels experienced in primary ageing. This subsequently leads to high levels of senescent cells that speed up ageing.

What Does ageing Do to You?

After learning about the differences between both ageing processes, let's take a look at their effects on the physiological level.

Effects of Primary ageing

Since primary ageing is linked to a buildup of cellular damage over time, it leads to: 

• A weakened immune system
• Loss in skin elasticity and firmness
• Increased fine lines and wrinkles
• Hair loss and graying hair
• A decline in cognitive functions
• Impaired hearing and vision
• Reduced ability to cope with stress
• Loss in muscle mass and bone density
• Slower heart rate

Effects of Secondary ageing

On the contrary, secondary ageing processes are often related to illnesses and disabilities like:

• Alzheimer’s disease
• Arthritis
• Cancer
• Cardiovascular diseases
• Diabetes
• Forms of self-harm
• Kidney disease
• Lung diseases
• Strokes

The Interplay Between Primary ageing and Secondary ageing

As noted above, primary ageing represents the slow decline of cells and tissues. Secondary ageing, on the other hand, is more directly linked to chronic disease development as a result of external factors. However, both ageing processes are not wholly independent of each other. In fact, the effects of normal ageing can impact secondary ageing and vice versa.

To clarify, let's take the example of arterial stiffening. According to Boutouyrie and Sønder in Early Vascular ageing, your arteries harden with age, a sign of primary ageing. However, arterial hardening can also be accelerated by secondary ageing, due to health diseases like diabetes.

Can ageing Be Prevented or Reversed?

Since primary ageing is brought about by the slow deterioration of cellular structure and function, it cannot be prevented or reversed. However, the impacts of some age-related changes caused by primary ageing can be lessened by adopting healthy practices. For instance, the gradual loss in bone density can be managed through physical activity.

Conversely, the secondary ageing process is mostly due to a mix of environmental factors and lifestyle choices. By becoming healthier and more active, most chronic diseases like heart diseases and high blood pressure can be prevented. Certain health conditions like obesity and hair loss can even be reversed with dietary changes and treatments.

7 Ways to Promote Healthy ageing

To combat the effects of both ageing processes, adopt healthy habits in your daily routine.

1. Caloric Restriction

Yes, we've mentioned that the primary ageing process cannot be prevented or reversed. But there is a scientifically proven method to slow it down — caloric restriction. While a healthy and well-balanced diet is key to healthy ageing, caloric restriction goes one step further to slow down the ageing process.

Researchers at the Washington University School of Medicine in St. Louis shared that participants on the low-calorie diet, consuming only 1,800 calories a day, experienced lower levels of triiodothyronine (T3) and tumor necrosis factor alpha (TNF). These changes reduced metabolic rate and oxidative damage, which help to slow down normal ageing.

Make sure to eat 100% of the recommended proteins, vitamins, and nutrients so that you experience the full benefits of a low-calorie diet.

2. Sun Protection

Sun damage results in wrinkles, sun spots, and drier skin. Too much sun damage can also result in premature skin ageing and increase your risk of skin cancer.

To prevent this, take simple steps to protect your skin from harmful ultraviolet (UV) rays. Use a broad-spectrum sunscreen with SPF 30 and avoid the sun between 10 a.m. and 4 p.m. If you're going to be out in the sun for a while, wear sun-protective clothing, a pair of sunglasses, and a hat to avoid being sunburnt.

3. Anti-ageing Skincare Routine

To further counter skin-related age changes, use anti-ageing products in your skincare routine. This is especially so for older adults in their 40s and onwards.

Go for topical skincare products that focus on tightening and firming your skin. For instance, YORA's Conditioning Face Balm contains vitamin C and Suberlift™ to reduce the appearance of fine lines and wrinkles.

At the same time, include hydrating products like the Revitalise Face Serum to counter increased skin dryness, a common issue in mature skin.

4. Avoid Unhealthy Habits

Common vices like smoking and alcohol consumption are part of secondary ageing. These habits increase cellular damage and accelerate ageing.

Based on a 2017 study in the International Journal of Environmental Research and Public Health, smoking is the number one risk factor of chronic diseases and cancer. More than 400,000 people die prematurely in the United States because of smoking.

Alcoholism is another major risk factor for numerous health conditions like diabetes, cardiovascular diseases, and liver disease. According to the National Institute on Alcohol Abuse and Alcoholism, alcohol-related death is "the third leading preventable cause of death in the United States".

The bottom line here is that lifestyle choices play a major role in speeding up secondary ageing. As such, it's best to quit and avoid unhealthy habits altogether to promote healthy ageing.

5. Physical Activity

Instead of indulging in vices like smoking and alcohol, get your heart rate pumping. Physical inactivity is a risk factor for chronic diseases and reduced life expectancy. Exercise can be used to counteract some effects of primary ageing such as reduced bone density and muscle mass.

To counter these age-related changes, exercise by walking, swimming, or cycling. These low-impact physical activities do not need much time, cost, or effort but still provide immense health benefits.

6. Health Checkups

While most age-related changes associated with primary ageing cannot be stopped, it's possible to pick up early signs of it. This is where health examinations are useful.

A comprehensive health checkup can detect risk factors for diseases that may be due to primary ageing and secondary ageing. Early diagnosis and the right treatment plan can help manage symptoms of chronic illnesses to promote a better quality of life in old age.

If you're below 40 years old, it's recommended to get a medical checkup every five years. For older adults above 40 years old, a health assessment should be done every one to three years.

7. Mindfulness Meditation 

As you age, you may find it more difficult to fall asleep or stay asleep throughout the night. This is a natural part of the primary ageing process. The Sleep Foundation explains that “older people spend more time in the lighter stages of sleep than in deep sleep”. This age-related change may also account for the higher rate of sleep disorders, like insomnia, among the aged.

Additionally, external factors such as a spouse who snores or drinking coffee just before bedtime can affect the quality of your sleep. Similarly, negative thoughts that create worry, anxiety, or fear can also hamper your efforts of pursuing a restful slumber.

To help you sleep better at night, give mindfulness meditation a try. Mindfulness refers to being fully present — paying attention to where you are and what you’re doing. You can practice being mindful through meditation, which is how the term “mindfulness meditation” is conceived.

For tackling sleep problems, mindfulness meditation helps to quiet down active thoughts. This is evident from a 2011 study by the Yale University School of Medicine, USA. The researchers discovered that meditation lowered activity in the default mode network (DMN) — brain activity responsible for wandering thoughts and self-referential emotions.

And that’s not all, mindfulness meditation has also been proven to slow down the deterioration of an ageing brain. A 2015 study in the Journal of Frontiers in Psychology highlighted “less age-related gray matter decline” in participants who meditated compared to those that didn't. Another 2011 study in the Journal of Psychiatry Research found that eight weeks of mindfulness meditation enhanced cortical thickness in the hippocampus — the brain structure that controls learning, memory, and emotional control. This suggests that meditation not only slows down age-related cognitive decline but may also improve brain plasticity over time.

As such, practicing stillness will aid in cognitive functioning and promote peace of mind.

Adopting an Ageless Approach

Instead of looking at ageing as something that should be despised, embrace the joys that healthy ageing can bring about. Older people are not necessarily less healthy, capable, or active than their younger counterparts. With the right understanding of how primary ageing and secondary ageing take place, it's possible to age healthily and gracefully.

To ensure a higher quality of life in your golden years, make the right lifestyle choices in your daily life now. By eating well, engageing in physical activities, using the right skincare products, and avoiding unhealthy habits, healthy ageing is achievable. It's time to start adopting an ageless approach in life.