Does stress cause heart problems? What the science says…

What do scientists already know about the heart and mental health connection?

We know that people with mental health problems such as anxiety and depression are more likely to experience heart attacks, strokes, abnormal heart rhythms and the risk factors for them such as high blood pressure.

For years, the focus was on the idea that mental health problems lead people to make less healthy lifestyle choices, putting them at a greater risk of heart disease.

But although this might account for some of the risk, research now suggests there’s also a more direct biological connection between what’s going on in the brain and heart health.

How is the brain connected to the heart?

There’s a part of the brain called the lower brainstem that sends signals which control heart rate and blood pressure. This is important because if we are faced with a threat, such as a tiger, we need the body to be able to act quickly.

One way it gets us ready for this ‘fight or flight’ response is to raise our heart rate and blood pressure, so more blood is pumped to our muscles.

But when people have anxiety or face chronic stress, we think the lower brainstem is getting ‘confused’ and sending signals to raise our heart rate and blood pressure when it does not need to.

What are you doing to better understand this biological connection?

My research, funded by British Heart Foundation, is exploring how another part of the brain, the hypothalamus, is sending signals to the lower brainstem.

The hypothalamus is the part of the brain that acts like a master control centre for our response to stress. One of the ways it does this is by releasing a hormone called CRH (corticotropin-releasing hormone).

We’ve shown that cells that release CRH in the hypothalamus send signals to cells in the lower brainstem that release another hormone called GLP-1 (glucagon-like peptide-1).

GLP-1 is probably best known as being the hormone that is mimicked by weight loss injections such as Wegovy, which make you feel full more quickly, helping you lose weight. But the cells in the brain that make GLP-1 also control heart rate and blood pressure.

We are looking at the pathway between CRH cells in the hypothalamus and GLP-1 cells in the lower brainstem in mice. We see what happens when the mice are exposed to stress and measure the effects on heart rate and blood pressure. And we are investigating what happens when we block or trigger this pathway between the CRH and GLP-1 cells.

We are also mapping which other parts of the brain are activated when the mice are exposed to stress and seeing if these might also be involved in regulating signals that control blood pressure and heart rate.

How might this research help us treat heart and mental health conditions in future?

If we can pin down the biological pathway that links stress response in the brain with how the brain is regulating blood pressure and heart rate, this will allow us to develop new medicines targeting the specific hormones.

We’ve already seen how this approach, focusing on a particular hormone, has been a game-changer with obesity treatment. In the case of obesity, the new weight loss injections target the GLP-1 hormone. In the coming decades, perhaps we’ll see something similar that targets a hormone involved in stress.

Also, work like this is important as it raises awareness about the biological basis of stress and mental health problems. It can help reduce the stigma and encourage people to seek the appropriate treatment, just as they would for a physical health condition.

What other exciting research is happening in mental and heart health?

Some researchers are looking at this question from the opposite direction, exploring how the brain senses and responds to physiological changes in the body.

For example, some studies have shown that simply increasing someone’s heart rate experimentally can be perceived as unpleasant by the brain, creating a feedback loop that worsens stress responses.

There’s also lots of promising research looking at the role of the gut and its connection to both heart health and mental health problems.

What to read next...