Until now, the process of aging has been an inevitable part of human life. As time goes on, the human body undergoes changes at the cellular and molecular level that eventually lead to visible signs of aging - up to and including age-related diseases. A healthy lifestyle that includes regular physical activity, a balanced diet, sufficient sleep and avoiding harmful habits such as smoking is often regarded as the key to slowing down the aging process. But is a healthy lifestyle actually enough to stop aging and halt the aging process? And if not: does a healthy lifestyle at least significantly slow down the aging process?
Why do we age?
The biological aging process
The biological aging process is a complex interplay of genetic factors, environmental influences and lifestyle factors. Over time, cells lose functionality, and the body becomes more susceptible to diseases and degenerative changes. There are a number of factors that can influence this process by changing the speed at which it progresses. First, however, let's look at how aging can be divided into subcategories.
Primary aging
A basic distinction is made between primary and secondary aging. Primary aging is caused by cellular aging processes and thus defines the maximum achievable lifespan for a species. Primary aging comprises the biological processes that take place naturally in the body and cause us to age. For example, our body needs ATP for muscle contraction, among other things, and ATP is produced in the mitochondria. However, the production of ATP releases free radicals, which over time cause the mitochondrial DNA to mutate. As a result, the mitochondria can no longer produce ATP in the original way (oxidative phosphorylation + citric acid cycle), but only through the citric acid cycle, which creates an excess of electrons that causes various kinds of cell damage contributing to aging. No matter how healthily we live, we will not be able to prevent this aging process through a healthy lifestyle, because each of us needs ATP and the production of ATP automatically creates free radicals, which over time result in cell damage.
Secondary aging
The secondary aging process can be the result of, for example, diseases, lack of exercise, poor diet, poor air or the use of addictive substances. It occurs as a consequence of an (unhealthy) lifestyle. Secondary aging is therefore the part of aging that can actually be prevented by a healthy lifestyle.
Can primary and secondary aging be distinguished from each other?
The two subcategories serve rather to make clear that there are aging processes that cannot be influenced by a healthy lifestyle, but take place naturally in our body, no matter how healthily we live. In reality, however, primary and secondary aging do not really involve different biological changes at the molecular or cellular level. Rather, a poor lifestyle accelerates the aging process that takes place naturally and cannot be prevented without artificial intervention.
Limits of a healthy lifestyle
So anyone who pursues a healthy lifestyle in order not to age is merely preventing the part of aging that occurs in addition to the natural aging process, but not the natural aging process itself. And this is where rejuvenation research comes in.
Rejuvenation research and primary aging
Rejuvenation research aims to reverse aging. Unlike people who aim to prevent secondary aging by living healthily, rejuvenation research aims to reverse primary aging in addition to secondary aging. Since primary aging determines the maximum lifespan a species can reach, successful rejuvenation research would not only ensure a healthier life, but even a longer, healthier life. If rejuvenation therapies were applied and improved regularly, it would even be conceivable that the maximum lifespan would increase significantly (Longevity Escape Velocity).
Does a healthy lifestyle at least significantly slow down the aging process?
First of all: this question is not easy to answer, and perhaps that is why it is not yet widely known that a healthy lifestyle has a comparatively small effect. But what makes this question so hard to answer?
To give a well-founded answer to this question, all options for a healthy lifestyle would have to be considered. In addition, you would need measurements of the extent to which this or that lifestyle affects mean and maximum lifespan. However, to capture the effect on lifespan in humans, a corresponding study would have to run for several decades - and so far there are not many of those. Nevertheless, we have taken a look at the available data for you.
Calorie restriction as one of the most effective lifestyle interventions
Calorie restriction is the reduction of energy intake without malnutrition. It is considered one of the most effective lifestyles for a long, healthy life.
Calorie restriction (CR) is, to date, the most successful intervention to delay ageing progression or the development of age-related chronic diseases.1
And yet calorie restriction probably only extends life expectancy by 2-3 years.2
So the intervention that is considered the most effective probably only has a life-extending effect of 2-3 years. This effect is so small that most people would probably accept living 2-3 years less rather than reducing their calorie intake. After all, it is often not easy to reduce your calorie intake, or it can become expensive over time if you instead take so-called CRMs (caloric restriction mimetics), which are supposed to produce the positive effects of calorie restriction without you having to watch your calorie intake.
Blue Zones - regions of longevity
Blue Zones are regions in which the people living there live longer on average than the average person living in other regions. The figures that show this are mostly based on demographic data. Blue Zones include, for example, Okinawa in Japan, Sardinia in Italy and Loma Linda in the United States.
Blue Zones are so interesting because you can look at the lifestyle of the people living there and draw conclusions about which lifestyle is particularly healthy, either by comparing the lifestyles of the different Blue Zones with each other to find commonalities, or by looking for differences from the regions that are not Blue Zones.
It can therefore be assumed that people who live in the Blue Zones do a lot of things "right" with their lifestyle. So how much longer do these people live, who do a lot of things right, i.e. live very healthily?
In 1995, the mean life expectancy of the inhabitants of Okinawa was 1.5 years higher than that of the inhabitants of mainland Japan, and the difference in maximum life expectancy was 3.8 years. Compared with Americans, the mean lifespan is 4.9 years higher - still very little.3
So even people who live very healthily - whatever their healthy lifestyle looks like - live on average only 5 years longer than people who lead an average lifestyle.
Another (possibly even simpler) way to measure the effect of a healthy lifestyle with today's means is to compare the life expectancy of different countries. Japan, for example, is known for having one of the highest life expectancies in the world overall. Reasons for this are its well-developed healthcare system, its high hygiene standards and above all its healthy diet: lots of vegetables, fish, seafood, rice and green tea. Nevertheless, although Japan ranks 4th in the list of all countries by average life expectancy, it is only 4.2 years ahead of the USA, which ranks only 48th.4
Conclusion: Is it enough to live healthily in order not to age? Is it at least enough to live healthily in order to age healthily?
No! A healthy lifestyle only prevents secondary aging, which - as the name already suggests - is not the "main aging process", but merely accelerates it. So with a healthy lifestyle, you are only preventing the aging process, which is happening anyway, from happening even faster. A healthy lifestyle can influence the speed of the aging process, but it cannot stop it. This is also where the 3-5 years come from that you can gain with today's measures for a "healthy lifestyle".
Whether that is enough for you, i.e. whether you see no need to campaign for more rejuvenation therapies instead of or in addition to a healthy lifestyle, even though rejuvenation therapies could reverse primary aging and thus potentially bring about a considerably greater increase in maximum lifespan, is something everyone has to decide for themselves.
Sources
- López-Lluch G, Navas P. Calorie restriction as an intervention in ageing. J Physiol. 2016 Apr 15; 594(8): 2043-60. doi: 10.1113/JP270543. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4834802/ (last accessed: December 6, 2023)
- de Grey AD. The unfortunate influence of the weather on the rate of ageing: why human caloric restriction or its emulation may only extend life expectancy by 2-3 years. Gerontology. 2005 Mar-Apr; 51(2): 73-82. doi: 10.1159/000082192. The Unfortunate Influence of the Weather on the Rate of Ageing: Why Human Caloric Restriction or Its Emulation May Only Extend Life Expectancy by 2-3 Years | Gerontology | Karger Publishers (last accessed: December 6, 2023)
- Willcox BJ, Willcox DC, Todoriki H, Fujiyoshi A, Yano K, He Q, Curb JD, Suzuki M. Caloric restriction, the traditional Okinawan diet, and healthy aging: the diet of the world's longest-lived people and its potential impact on morbidity and life span. Ann N Y Acad Sci. 2007 Oct; 1114: 434-55. doi: 10.1196/annals.1396.037. https://citeseerx.ist.psu.edu/document?repid=rep1&type=pdf&doi=d60c36654c81af95c02fdf8e428971fab2f392c6 (last accessed: December 6, 2023)
- https://de.wikipedia.org/wiki/Liste_von_L%C3%A4ndern_nach_durchschnittlicher_Lebenserwartung (last accessed: December 6, 2023)
Author: Sandra