"Cliff-like aging" really exists! Scientists reveal two key time points for accelerated aging of the human body

Tuchong Creative

Such plots often appear in movies and TV dramas, where the protagonist's hair turns white overnight due to excessive sadness, and suddenly looks like he has aged by a dozen years. Although this is an artistic exaggeration, in fact, "cliff-like aging" really exists in reality. Scientists have found that after two time points, humans will age faster.

On August 14, 2024, a study published in the journal Nature Aging by a research team from Stanford University showed that the human body does have two important accelerated stages in the aging process, at around 45 and after 60 years old, but with different emphases.

Although the acceleration does exist, research also suggests that we can adjust our lifestyle habits more specifically to adapt to these changes and maintain health.

Aging is a complex physiological process that is not only related to age, but also involves the influence of many factors such as physiology, psychology, environment and lifestyle.

In appearance, aging is manifested by decreased skin elasticity and luster, hair loss, lighter hair color, changes in body shape and slower walking speed; physiologically, it involves the weakening of the functions of important organs and immunity; psychologically, aging can be manifested by decreased memory and concentration, and a decrease in curiosity and adaptability to new things.

In clinical practice, aging is often assessed by testing multiple indicators such as bone density and inflammatory response markers, or by using a grading scale, such as observing the degree of palpitations and shortness of breath after exercise to assess heart function.

All complex biochemical reactions in the human body need to be performed by protein molecules. How does "cliff-like aging" manifest itself at the cellular and molecular level?

The Stanford University study followed 108 healthy participants aged between 25 and 75 from different races for many years. The research team collected biological samples from the participants every 3 to 6 months, including blood, feces, and swab samples of the skin, mouth and nose. By analyzing 135,239 biological features in 5,405 biological samples, including transcriptomics, proteomics, metabolomics and cytokines, the results showed that about 81% of the molecular markers in the human body showed significant changes during the aging process, especially in the two stages around 45 and 60 years old.

The number of differentially expressed molecules and microorganisms during aging, with two local peaks detected at 44 and 60 years of age

At the first turning point around the age of 45, the aging of the skin and muscles accelerates significantly. The elasticity of the skin is closely related to the function of the extracellular matrix. The extracellular matrix is ​​composed of collagen, elastin and glycosaminoglycans, which provide structural support for the skin. The accelerated degradation of these molecules may lead to obvious changes in appearance.

From the age of 30, muscle mass decreases by 3-8% every decade on average, and becomes more obvious after the age of 45. And with the weakening of the regulatory function of actin, muscle strength and flexibility are further affected.

In addition, during this transition period, the body's metabolic activity for fat, alcohol and caffeine is significantly weakened.

After the age of 60, in addition to the above changes, the acceleration of aging is more reflected in the increased susceptibility of the human body to various diseases.

The levels of phenylalanine, urea nitrogen and glucose in the blood increased significantly, and these indicators are closely related to heart dysfunction, renal dysfunction and type 2 diabetes. Unsaturated fatty acids help prevent atherosclerosis, improve blood vessel elasticity and reduce inflammation. The activity of this type of fatty acid synthesis pathway decreases significantly after the age of 60, affecting its protective effect on the cardiovascular and cerebrovascular system.

Previous statistics show that in the United States, the incidence of cardiovascular and cerebrovascular diseases is about 40% between the ages of 40 and 59, and rises to about 75% between the ages of 60 and 79. The results of this molecular study are very close to this.

In addition, after this transition period, dysfunction of chemokines is more common. This is a class of molecules responsible for recruiting immune cells and promoting inflammatory responses. Its abnormal activity can easily lead to chronic inflammation and increase the risk of tumors.

The study also pointed out that many biological reactions interact with each other during the aging process, exacerbating the aging process. For example, lipid metabolism disorders may lead to a decline in cell function and further weaken other metabolic functions. Therefore, we should try our best to avoid problems in multiple links at the same time in the elderly stage and take preventive measures in advance according to age characteristics.

For example, according to the research results, people should actively reduce their intake of fat, alcohol and caffeine after the age of 45, increase exercise to slow down the loss of muscle mass and enhance cardiopulmonary function. After the age of 60, people should pay more attention to protecting the functions of important organs, be cautious about chronic inflammation and be alert to the risk of tumors.

With advances in medicine and improved living conditions, life expectancy continues to increase across the globe.

Although aging is inevitable, we look forward to future research continuing to reveal the characteristics of aging and helping people stay healthier for as long as possible as they age.

This article is a work supported by the Science Popularization China Creation Cultivation Program. Author: Xu Sijia

Reviewer: Liang Qianjin, Professor of School of Life Sciences, Beijing Normal University

Produced by: China Association for Science and Technology Department of Science Popularization Produced by: China Science and Technology Press Co., Ltd., Beijing Zhongke Xinghe Culture Media Co., Ltd.