Okinawa, Japan. Sardinia, Italy. Nicoya, Costa Rica. Three points on the map that are far from each other but which, nevertheless, have a surprising feature in common: the life expectancy of their inhabitants is very high, over 100 years.

These are three of the so-called Blue Zones: places where people not only live longer but in better health. So what’s their secret? 

Beyond diet or physical activity, researchers agree on one key factor they all share: their inhabitants live in environments that favour relaxation and social relationships and promote a strong sense of purpose in life, as well as experiencing low levels of stress. 

And this is no minor detail. Although stress is a natural response by the body that enables us to react to dangerous situations, when it goes on for too long it can become a silent enemy for our health.

The scientific evidence is clear: chronic stress is a risk factor in the development of neurodegenerative, cardiovascular, immunological and mental diseases, affecting not only our quality of life but also our years of life. 

In this joint article we explore how stress, when it becomes chronic, can erode the foundations of our health. We’re accompanied by three researchers from the CaixaResearch network who are studying the effects of stress from different angles: mental health, the heart, the immune system and the brain.

 

How does stress affect the cardiovascular system?

According to the World Health Organisation, cardiovascular disease is the leading cause of death globally. Coincidentally, eight of its major risk factors (obesity, high blood pressure, high cholesterol, diabetes, smoking, lack of exercise and inadequate diet and sleep) also have a high correlation with stress and the effect on key organs, such as the brain.

“Stress affects all aspects of life, especially cardiovascular health” explains Valentí Fuster, one of the world’s most renowned cardiologists, researcher and director of the Carlos III National Centre for Cardiovascular Research (CNIC) and Mount Sinai Hospital in New York, in this MediaHub interview. 

The fact is that chronic stress has a cumulative effect on our cardiovascular system: it raises blood pressure, promotes inflammation in the blood, alters heart rhythm and can reduce blood flow to the heart. In the long term, all this can damage blood vessels and increase the risk of atherosclerosis and even heart attack. Moreover, in addition to these physiological effects it can also cause behavioural changes: it increases the likelihood of adopting unhealthy habits (such as smoking, alcohol or substance abuse, imbalances in diet and relaxation), lengthening the list of risk factors and increasing the likelihood of cardiovascular damage. 

“However, stress is also a personal thing. We live in a 100% consumerist and competitive world but everyone has to think about what they want in life” notes Valentí. “Often, competitiveness comes because you want to be in a much more advantageous financial position. But a much more primitive and less stressful life can also be rewarding. There are seven places in the world, the so-called Blue Zones, where people live in community, eat better and have less stress. So it’s essential to stop and think: What do I want? And how can I survive?”

 

What’s the impact of stress on the brain?

We’ve all heard of the famous “stress hormone” called cortisol. “If the levels of this type of hormone increase, we also observe alterations in the brain. From strokes to cognitive dysfunction and mental health problems” notes Paulo Pinheiro, a CaixaResearch researcher at the Centro de Neurociências e Biologia Celular in Portugal.

His team is working to provide an accurate description of the molecular mechanisms that link stress to the neuronal alterations causing such consequences.

“The effects of stress on the brain range from reduced neuroplasticity and memory problems to the development of anxiety disorders and depression. We know this is triggered by overactivity of the amygdala, a region of the brain that’s involved in fear responses” says Pinheiro. “We’ve also seen that it severely affects other regions, such as the prefrontal cortex, which is involved in higher reasoning, decision-making and impulse control, resulting in a shorter attention span, poor judgement and greater impulsivity“.

According to the Portuguese researcher, there appear to be differences between men and women in their response to chronic stress, although this line of research is still being developed. “Men seem to be more prone to cognitive impairment, whilst in women the emotional effects predominate”. Even so, a common feature has been found in both sexes: “If stress is too intense and prolonged, it can cause irreversible changes in the brain” he adds.

 

How does stress affect the immune system?

Some people seem to get sick more easily during a period of high stress whilst others don’t fall ill until the stressful period has ended, for instance once they’re on holiday. This difference has a biological explanation: stress produces an inflammatory response that affects the immune system in two seemingly opposite ways. Initially, it may be beneficial in combating pathogens but, in the long term, it weakens our immune response.

“There are well-documented links between chronic stress and the immune response: stress increases peripheral inflammation, which reaches the brain in the form of pro-inflammatory molecules, activating the immune cells in the brain. This triggers a state of neuroinflammation, which contributes to cognitive dysfunction” explains Pinheiro.

In fact, “This pro-inflammatory state can spread throughout the body and affect health in general” says Ayako Nakaki. Ayako is a “la Caixa” Foundation fellow, reasearcher at the Fundació de Recerca Clínic Barcelona-Institut d’Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS) and participant in the IMPACT-BCN project, which focuses on describing the impact of lifestyle and maternal stress during pregnancy on the health of women and their babies. 

“A large number of studies have shown that more than 20% of pregnant women experience stress and anxiety. We hypothesised that reducing this stress would improve the inflammatory state of mothers and, with it, the neurodevelopment of their children”. The results were clear. “Lowering stress levels and following a Mediterranean diet improved children’s socio-emotional development during the first two years of life”. However, although these results are encouraging, “more research is still needed to fully understand the why, and the biological mechanisms behind this phenomenon” adds Nakaki.

 

How can we reduce stress to improve health?

Although much remains to be discovered, Ayako believes that, in the case of pregnant women, screenings aimed at monitoring stress levels could be included in routine medical follow-ups, thereby improving the health of mothers and their children. 

Solutions of this kind are more necessary than ever. Even though stress has become an increasingly normalised part of our lifestyles, it’s still a serious problem for society. “It’s often the main cause of major health problems such as dementia, diabetes, heart disease, obesity and substance abuse. But the fact that it’s difficult to detect and the lack of tools to quantify it delay its diagnosis until it becomes a clinical pathology” explains Paulo. So what can we do to stop it in time?

“Therapies based on lifestyle changes, such as meditation, physical exercise, a balanced diet and adequate rest, can be effective in preventing stress-related cognitive decline. But perhaps most importantly, it’s vital to acknowledge there’s a problem which needs to be addressed. The numbers don’t lie: stress-related disorders represent a huge cost for health systems” concludes Pinheiro.

Valentí Fuster goes one step further, highlighting the social context. “Right now, the consumer society is beating disease prevention… We have to create a culture of health and quality of life, in which prevention plays a central role. In other words, if we all believe that taking care of ourselves and having a good quality of life in our 70s, 80s or 90s is important, we can win the battle. And the economy will also benefit. I always give a very easy example with traffic lights: if there were no traffic lights, there would be enormous chaos. Traffic lights help us circulate so that everything works. It’s the same with health. Prevention is traffic lights; it’s indispensable for everything to work. I’m hopeful about this because social thinking is changing… And we’re increasingly valuing well-being as a common good“. 

Obviously we can’t all move to Okinawa, Sardinia or Nicoya but we can take inspiration from their habits to build our own Blue Zones: physical and mental spaces where rest and relaxation, meaningful relationships and a sense of purpose play a central role. After all, taking care of emotional well-being isn’t a luxury but an investment in health.