The tortoise has an average life expectancy of over 100 years. It is not surprising that the genomic composition of the tortoise has sparked interest among many curious researchers attempting to better comprehend the genomic determinants of longevity and metabolism. However, even among humans, these average numbers have been far superseded. In 1997, when France’s Jeanne Calment breathed her last, she was the oldest living person in the world at 122 years old. Currently, 118-year-old Kane Tanaka of Japan is the world’s oldest person alive. Wonder what has kept these record-breaking supercentenarians going?
- Longevity is the life expectancy of an individual living thing. It refers to how much time a person will live,
- Genetics, lifestyle, metabolism, and our environment are a few major factors that impact one’s longevity,
- Studies have shown that moderately restricted caloric intake can slow one’s metabolic rate.
What is Longevity
In simple words, longevity means existence for a long duration. In the context of human life, it refers to how long an individual lives. The term is often synonymous with life expectancy. Well, how long a person’s life is determined by a number of factors such as genetics, environment, and lifestyle. Let’s take a deeper look at each of these factors.
Factors that affect Longevity
Nine different genetic hallmarks known to contribute to longer lifespans have been identified thus far; these include genomic instability, cellular senescence (ageing), deregulated nutrient sensing (metabolic activities can exert stress on our cells, causing them to age faster), and epigenetic alterations, among others. In simpler words, each of these hallmarks is linked to alterations in metabolism. Besides the individual’s genetic composition, their environment and lifestyle play a crucial role in determining their longevity.
With developments in health care systems and improved accessibility to medical care, we have historically seen a decline in the incidence of infectious and other chronic diseases, as well as mortality rates worldwide. As a result, the global average life expectancy has increased from 45 years in 1900 to the late 70s today.
Ongoing research among nonagenarians and centenarians suggests that the lifestyles of these older adults reflect several commonalities, such as non-smoking status, healthy body weight, and low-stress levels—all of these results in a lower likelihood of developing age-related chronic diseases. Research also suggests that most long-lived individuals are women. While we may fancy adding more candles to our birthday cakes, it is more important to focus on living a healthy life.
Metabolism is a process of life-sustaining chemical reactions continually occurring in your body that converts what you consume into energy. Your metabolic fitness level depends on how efficiently your body generates and processes energy. The doubly labelled water method is considered the gold standard for studying metabolism in most research. It tracks the amount of carbon dioxide exhaled by an individual during daily activities.
How are Metabolism and Longevity related?
In the early 20th century, biostatistician Raymond Pearl hypothesized that an organism’s metabolic rate is considered to be inversely proportional to the maximum lifespan. This implied that species that live fast will die young, whereas those that live slower owing to a slower metabolic rate will actually live longer. This was considered an advancement to the ‘rate of living’ theory.
However, more recent findings from mice studies suggest that the theory that higher energy expenditure may imply a lower life span may no longer be true, after all. There is little corroboration for the argument that the number of breaths one takes, oxygen metabolism, and heartbeats ascertain a person’s lifetime. The theory gains ground when smaller species with faster metabolism are compared with larger ones with slower metabolism but it does not conclusively illustrate the disparities within species.
The leading researcher of the study, Dr Pontzer, says in The New York Times that for the first month of life, babies have the same metabolic rate as their mothers, as opposed to the general perception that infants burn calories faster. In the study, the start of the metabolism decline was only witnessed at age 60. This downturn was attributed to the deterioration in the functioning of vital organs as people age.
What can you do to improve your Metabolic Control of Longevity?
Using modern statistical modelling analyses, recent research has predicted that records of the longest living person in the world are likely to be broken by 2100 and that people will likely live anywhere between 125 and 130 years. While experts continue to analyse these predictions further, there is considerable knowledge about what we can do in an effort to improve our longevity.
One of the most popularised ways to influence your metabolism is caloric restriction reducing the number of total calories consumed in your daily diet. One easy way to do this is to practice portion control. According to Herman Pontzer, an evolutionary anthropologist at Duke University and author, how we eat and use up our calories are more important than our fixation with what to eat.
Studies have shown that even a moderately restricted caloric intake can slow down your body’s metabolic rate so that it uses less energy to sustain everyday functions. Over time, this would result in lower oxidative damage to cells and tissues, as suggested by longevity researchers. Luigi Fontana, an internist who led the Washington University trial proposes that the answer may lie in specific insulin pathways rather than metabolism decrease.
“What we are finding now is that it’s not the number that matters. Genetics, the composition of the diet, when you eat, and what’s in your microbiome influences the impact of calorie restriction,” says the lead author and researcher of the calorie restriction study. In human beings, the process of ageing is governed by a metabolic clock. There is ample evidence that living a sedentary lifestyle, a poor nutritional intake, and exposure to environmental pollutants may accelerate age-associated pathologies.
These include type 2 diabetes, cardiovascular diseases, and several forms of cancers. While research on whether cutting calories helps add more years to your life may not be crystal clear, caloric restriction is associated with a reduction in the rates of cancer and lifestyle diseases.
Preventive health check-ups, a balanced diet, exercise, and nurturing your mental health can add a few extra years to your life. Remember, to change your lifestyle and sustain any new habits, be like the tortoise and introduce them at a slow and steady pace! Most of us have grown up reading or listening to Aesop’s popular fable The Tortoise and the Hare racing each other. The moral of the story—slow and steady wins the race—was perhaps one of the first lessons we learned in our formative years! This tale serves as a good metaphorical reminder that human life is analogous to a marathon and that those who are more steady-going and relentless are likely to live longer.
Disclaimer: The contents of this article are for general information and educational purposes only. It neither provides any medical advice nor intends to substitute professional medical opinion on the treatment, diagnosis, prevention or alleviation of any disease, disorder or disability. Always consult with your doctor or qualified healthcare professional about your health condition and/or concerns before undertaking a new health care regimen including making any dietary or lifestyle changes.