We have long known that stress can cause a cascade of physical problems, from a racing heart rate to sleep problems.

But just how harmful can it be? 

Experts have told MailOnline that mental turmoil may be just as deadly as physical illnesses. 

According to psychologist Dr Audrey Tang, prolonged stress can trigger a release of hormones that dramatically raise the risk of heart attack and weight gain — which could lead to obesity-related diseases. 

Dr Tang has revealed the warning signs that your stress levels are peaking, and are storing up physical problems in the years to come.

It comes as football manager Pep Guardiola appeared to demonstrate an alarming stress response at a post-match press conference this week following the disappointing 3-3 draw against Feyenoord in the Champions League. 

Manchester City boss was questioned about the cuts on his nose and scratches on his head that emerged after the game, to which he responded 'I cut myself', 'I want to harm myself’. 

His reference to self-harm prompted fans to express their concern, but the 53-year-old has since admitted he had been caught 'off guard' by the question adding that he didn't want to 'make light of the very serious issue'.

Chartered psychologist Dr Audrey Tang told MailOnline that stress can drastically affect the way we behave as well as impact us physically if it is what's called chronic — lasting for at least a few weeks.

Dr Tang said: 'Psychologists look for signs that stress is affecting you day to day. For example, if you aren't sleeping, if you aren't eating, if you're irritable, if you're not doing all the things that you love, if you're obsessing over something.'

Physically, the most common signs of chronic stress are chest pains, headaches and muscle aches.  

This is because stress causes the body to release too much of the hormone cortisol, which is produced by the adrenal glands that sit on the top of the kidneys. 

It regulates a wide range of bodily processes including blood pressure, metabolism, fertility and sleep-wake cycles.

As well as cortisol, the body releases a surge of adrenaline — an increase in both hormones is a result of the 'fight or flight' reaction that's triggered when we're under threat. 

Together, these hormones cause the blood vessels to constrict, which makes our heart have to work harder to pump blood around the body.

This can lead to heart palpitations and chest pains, as well as high blood pressure and pains in the muscles and head.

 'If the stress doesn't go away, that's when things like high blood pressure, heart attacks, all of those physical things are more likely to happen,' Dr Tang warned.

The NHS agrees that long periods of stress can our raise blood pressure, as well as causing headaches, blurred vison and chest pain.

Another sign that cortisol is at worryingly high is struggling to get to sleep, or waking up frequently during the night. 

Dr Tang explained that a lack of sleep can cause problems day to day and trigger behavioural problems like general irritability and carelessness. 

However, sleep deprivation doesn't just put us in a bad mood, in the long-term it can also impair metabolism and further increase your risk of cardiovascular diseases, according to experts. 

Dr Tang describes stress as a 'vicious cycle' as a lack of sleep also makes it harder for the body to regulate cortisol levels, worsening the problem.

Another sign to watch out for is a dramatic change in appetite.  

'Sometimes stress makes us not eat at all, but for others, it makes us eat lots, and that's the effect of the cortisol affecting our normal processing,' she said.

In addition, stress can make the body physically tense up as a way of guarding the body against injury and pain, according to the American Psychological Association.

This adds to muscle pain because the tissues are constantly taut.

Another sign your stress is at alarming levels is a significant loss of libido. 

According to the mental health charity Mind you may lose interest in sex or be unable to enjoy it.

That's because chronic stress can affect testosterone production resulting in a decile in sex drive. 

Although there are no specific treatments for stress, you should speak to your GP if stress is affecting your physical health. 

Studies show that stress should not be taken lightly.

One 2021 paper showed the mental health problem can cause sudden cardiac death, while a 2015 study showed a 50 per cent increased risk of early death due to chronic stress and depression.