As you age, certain body functions and processes shift. These physiological changes of aging affect multiple systems that impact cognition, cardiovascular health, muscle strength, bone density, weight status, sex hormones, and skin health. Many aging-related changes are involuntary. However, lifestyle modifications—such as sleep, stress, nutrition, and physical activity—can mitigate the effects of aging, promoting longevity and a greater quality of life.
Let’s break down what aging is, how it relates to longevity and the physiological changes that relate to each body system.
Aging is the decline in function resulting from the accumulation of cellular damage. [1] There is no single explanation for aging. Rather, aging is linked to changes in biological, physiological, environmental, psychological, behavioral, and social processes. Research continues to evolve on how these factors affect age-related chronic diseases. Genetics influence longevity; about 25% of the variation in longevity can be attributed to genetics. But, environmental, social, and lifestyle factors may play a larger role in a longer lifespan and healthspan. [1,2,3]
Aging is not always linear or consistent. It affects all body systems—as people age, they are more likely to experience several conditions simultaneously. By identifying certain aging processes to target with lifestyle modifications, researchers hope to slow the start and progression of diseases and instead establish a path towards a longer lifespan and greater healthspan. [2]
Longevity is the length of the lifespan (the time a person lives) regardless of internal physiological changes associated with aging. [4] So extending longevity means slowing or prolonging the aging process.
The physiological changes of aging are characterized by an alteration—usually a decline—in organ function, with these changes accumulating over time. Some aspects of aging are harmless to overall health, like the graying of hair. Other aspects can significantly impact functional abilities and quality of life. The effects of some age-related changes, such as decreases in hormone levels, are not isolated to one organ system. Instead, the consequences of low hormone levels, cognitive impairment, cardiovascular irregularity, or muscle and bone loss are compounded and can propel that progressive decline of health. [1,2,5]
Aging can affect the heart health and blood vessels. Research shows that low-density lipoprotein tends to creep up with age. High levels of LDL cholesterol—especially when there’s inflammation present—creates plaques or deposits in arteries, increasing arterial stiffness and hardening. This in turn restricts how much blood can pass through an artery, which increases the likelihood of having high blood pressure and heart disease. [6]
Bones are constantly remodeling. During this process, old bones are removed by osteoclasts (bone-degrading cells) and replaced with new bones by osteoblasts (bone-forming cells). [9]
During childhood and times of growth, the bone-building phase is the dominant phase. But with age, osteoclasts become more prominent and initiate bone breakdown. This causes bones to lose density and become weaker. And the risk of osteoporosis—a bone disease characterized by a decline in bone density and quality associated with aging—and fractures increases. [9,10]
Body composition refers to the percentage of fat or lean-body mass (that consists of muscle, bone, and water mass). Aging processes promote the breakdown of lean body mass and favor the accumulation of fat mass. [14] One reason for this shift in body composition is attributed to age-associated decreases in sex hormones—testosterone in males and estrogen in females. [15] In females, estrogen levels fall drastically after menopause. In males, testosterone levels decrease about 1%-2% each year after age 40 (although low testosterone levels can occur at any age). [16] Both of these hormones are involved in weight regulation and metabolism, and low levels are associated with weight gain typically in the midsection and abdomen.
Body composition and the accumulation of excess weight also impact metabolic health and blood sugar control. Your metabolism determines how many calories you need a day to maintain bodily functions (like breathing and digesting food) and any physical movement. Muscle has a higher metabolic rate than fat, meaning it requires more calories to carry out its essential functions. Decreases in lead body mass as you age means you need to take in less calories than previously to maintain weight. [17] Not doing so could lead to weight gain.
Loss of muscle mass and strength, known as sarcopenia, often accompanies aging. Research into the cause of sarcopenia is constantly evolving, and scientists believe its onset is likely related to neurological declines, hormone alterations (like those described above), nutrition, and/or exercise. Together, these age-related imbalances in normal cell processes contribute to sarcopenia, as signals for cell breakdown dominate signals for cell growth. [21,22]
Sarcopenia is associated with mortality. Lower muscle mass and strength lead to imbalances and frailty, which increases the risk of falls. [23]
The brain changes as we age. Shrinking neurons and changes to how those neurons communicate affect memory, recall abilities, problem-solving and multitasking capabilities, and attention span. [27,28]
A decline in sex hormones accompanies aging and contributes to a proinflammatory state.
Dehydroepiandrosterone-sulfate (DHEAS), a precursor for sex hormones, helps maintain energy, muscle and bone health, and sexual function. Low levels of DHEAS in women are associated with stress and poor sleep. Moreover, DHEAS decreases with age. Similarly, testosterone levels in males and estrogen levels in females decrease with age, affecting sex drive, sexual function, and bone and muscle health. [33-35]
The skin often provides the first visible signs of aging. Some people may notice wrinkles, pigmented spots, and loss of plumpness starting in their 20s or 30s. Skin aging is driven by multiple factors including collagen decreases (a protein in connective tissue that supports skin elasticity), alterations in facial fat and muscle distribution, genetics, and hormonal shifts. And environmental and lifestyle factors—such as UV light and smoking—can accelerate aging and leave noticeably visible signs of age earlier. [40]
While extending your lifespan can add years to your life, extending your healthspan helps you enjoy and stay active in those later years. InsideTracker is designed to help you live healthier longer by providing you with personal health analysis and a data-driven wellness guide. No matter what your age is now, it’s never too early or too late to invest in yourself. Tracking your biological age with InsideTracker's InnerAge 2.0 provides unique insights into how your body is aging, recommendations to improve on those markers of aging, and motivation for lowering or maintaining a lower biological age than chronological age.
Some aging processes are (eventually) inevitable. But, implementing small lifestyle changes to nutrition and exercise routines can prevent the early onset of aging and associated chronic diseases and extend your healthspan—the period of your life living in good health.
References:
[1]https://www.nia.nih.gov/about/aging-strategic-directions-research/understanding-dynamics-aging
[2] https://www.who.int/news-room/fact-sheets/detail/ageing-and-of-health
[3] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4822264/
[4] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3257745/
[6] https://www.nia.nih.gov/health/heart-health-and-aging
[7] https://pubmed.ncbi.nlm.nih.gov/33446313/
[8] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5696634/?report=classic
[9] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3383520/
[10] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7143872/
[11] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5818787/
[12] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7143872/
[13] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6950804/
[14] https://www.nature.com/articles/s41591-019-0565-5
[16] https://www.tandfonline.com/doi/full/10.3109/13697137.2012.707385
[17] https://www.ncbi.nlm.nih.gov/books/NBK133218/pdf/Bookshelf_NBK133218.pdf
[18] https://bmcmedicine.biomedcentral.com/articles/10.1186/s12916-020-01847-9
[19] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7468870/
[20] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7922336/
[21]https://journals.lww.com/co-rheumatology/Abstract/2012/11000/Sarcopenia_in_older_adults.7.aspx
[22] https://www.youtube.com/watch?v=t9wJ1ywLfog
[23] https://www.karger.com/Article/FullText/517099
[24] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4555150/
[25] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2804956/pdf/nihms131937.pdf
[26] https://pubmed.ncbi.nlm.nih.gov/32483625/
[27] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8627478/
[28] https://www.nia.nih.gov/health/how-aging-brain-affects-thinking
[29] https://pubmed.ncbi.nlm.nih.gov/26718417/
[30] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3256163/
[31] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8192763/
[32] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9372582/
[33] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3636678/
[34] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3756071/
[35] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5710003/
[36] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6750292/
[37] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6438434/
[38] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9216258/
[39] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5561416/
[40] https://pubmed.ncbi.nlm.nih.gov/31345325/
[41] https://pubmed.ncbi.nlm.nih.gov/27749441/
[42] https://pubmed.ncbi.nlm.nih.gov/28805671