The Shocking Link Between Stress and Lifespan

Chile is a developing country in South America. You might expect its life expectancy to be lower than in wealthier nations. However, on average, Chileans live 2 years longer than Americans.

Now, one might argue that this is because a significant portion of U.S. hospitals are privately funded, leaving most people in low-income households with limited healthcare access. But if that were the only factor, then we’d expect the gap to be much smaller in European countries with more equitable healthcare systems, like Norway right ? Surprisingly, the difference in life expectancy between the top and bottom 10% in Norway is comparable to that in the U.S. (refer Figure 1).

While it’s true that Norwegians, on average, do live longer than Americans, what intrigues me more is the strong correlation between income and life expectancy. Why is there a staggering gap of almost 15 years in life expectancy between the top 10% and the bottom 10%?

Before answering that, let’s try to estimate how long we’ll live based on our annual income.

Predicting Life Expectancy Based on Income

In the past few years, income inequality in Australia has been increasing, similar to trends in countries like the US and the UK. Given that income inequality has been shown to have a greater impact on life expectancy that the type of healthcare system (from the Norway example), we can attempt a fair comparison by extrapolating life expectancy based on income for Australians, who generally live longer than Americans.

But before you start calculating your own lifespan, keep in mind that I’ve adjusted this data for individuals born in 2024. If you’re a millennial, Gen Z, or Baby Boomer, cut yourself some slack.

The Numbers: Income and Life Expectancy

The reported annual income by percentile varies across most sources. According to the Poverty and Inequality (2024) report, the top 10% of Australian households earn approximately $5,248 per week after tax. I’ve crunched the numbers. Based on these figures, a male in the top 10% would have an after-tax annual income of around $137,000 ($273,000/2 per person), translating to a lifespan of up to 86 years. In contrast, people in the bottom 10% earn about $400 per week after tax, or roughly $21,000 per year, with an expected lifespan of 74.5 years.

We often assume that factors like diet, exercise, location, healthcare access, and education play major roles in longevity. However, studies show that none of these alone strongly correlate with life expectancy.  So, what is the most significant contributor to premature death?

The Answer: Chronic Stress

Not all stress is harmful. Short-term stress, or acute stress, is the adrenaline rush before a big race or a nerve-wracking meeting, which can be beneficial. It sharpens focus, increases blood flow, and suppresses inflammation.

But chronic stress is different. It kills us!

Chronic stress is constantly waking up early after late-night shifts, juggling multiple jobs, and barely making ends meet. This type of long-term stress kills.

How Chronic Stress Destroys the Body? (The Science)

When under stress, our body releases cortisol, a hormone that alters organ functions to help manage high-stress situations. In short bursts, cortisol isn’t harmful. However, prolonged elevated cortisol levels can cause severe physiological damage, including:

These physiological changes are linked to high cortisol levels: cardiovascular disease, type 2 diabetes, dementia, and gut disorders. Interestingly, these are the leading causes of death among low-income households.

So the chain reaction looks like this:

High stress (long-term) -> Physiological changes -> Chronic diseases -> Premature death.

People with higher incomes tend to live longer because they accumulate more wealth over time, allowing them to live a lower-stress lifestyle for longer.

Essentially, stress is the cigarette of the 21^st century. 

Other Factors Contributing to the Gap

Though chronic stress is a major factor, other variables contribute to the stark difference in life expectancy:

Smoking: is a timeless contributor. People in lower socioeconomic groups are significantly more likely to smoke, largely due to lower education levels. The strong correlation between education and smoking rates reinforces the role awareness plays in health outcomes.  

Education: Those in the top 10% of earners are typically more educated. Higher education levels are associated with increased health awareness, better job opportunities, and financial stability, all of which contribute to longevity.

Net Household Wealth: More than just income, total wealth is a better predictor of life expectancy. I should have pointed this out earlier, as what truly matters is not just how much someone earns, but how much they manage to save. A high net worth provides financial stability, allowing individuals to sustain themselves without a job for a longer period, thereby reducing financial stress.

How to Reduce Stress and Live Longer

In today’s high-stress environment, managing stress is more important than ever. Here are some effective ways to keep cortisol levels in check:

- Regular Physical Activity – Helps regulate cortisol levels and improves overall well-being.

- Stress Management – Meditation can lower stress hormone levels.

- Getting enough sleep - Poor sleep raises cortisol levels.

Final Thoughts

Income inequality isn’t just an economic issue. It is a health crisis. While we can’t eliminate stress entirely, understanding its impact on longevity gives us the tools to take control of our well-being.