You wake up later than planned, so it’s a rush to get everything sorted out ahead of the school run. While you’re waiting for the toaster, idiotically, you check your phone. Something has happened, and your timeline is a scalding-hot mess of the worst takes imaginable. One of your children has left their shoes somewhere unfathomable, and there’s an envelope on your doormat scolding you for driving in a bus lane.

You’re undeniably stressed, and your body’s likely to respond by ramping up the same biological systems that evolved to deal with inter-tribe disputes and mammoth attacks. But is there a downside to being stressed – and having these systems switched on – all the time? Take a calming breath, and let’s dig into the science.

“The most immediate effect we see in a stressful situation is a surge of adrenaline causing an increase in heart rate, blood pressure and breathing,” says Prof Kavita Vedhara, a specialist in stress and behavioural medicine at Cardiff University. “This is your fight-or-flight response, and it’s designed to prepare you to address the challenge you are facing.”

Within about 30 minutes of this rapid response, you’ll also experience a rise in cortisol, often (somewhat reductively) known as the stress hormone. “Again, this is very useful in supporting the fight-flight response because it regulates blood pressure, suppresses inflammation and increases the availability of blood sugars to increase energy,” says Vedhara.

This was all very useful centuries ago when most of what life threw at us was physical challenges. But now it’s fairly rare that we need to literally run away from – or physically fight – the source of our stress, and very easy for us to start worrying about someone being mean to us on the internet, or spend hours ruminating on an argument with our partner. The problem with this, broadly speaking, is that when your body diverts all its resources to fight or flight, it’s moving them away from areas such as digestion, repair and the immune system (sometimes referred to as the rest-and-digest systems). This is fine if it happens occasionally – it’s how we’ve evolved to operate – but if we’re chronically stressed, the body never gets time to catch up.

“Perhaps the most well-known issue associated with chronic stress is poorer immune function, which can increase risk of infections, make vaccines work less well, impair wound healing, and so on,” says Vedhara. “But chronic stress has also been shown to increase the risk of obesity, depressive illness and progression of neurodegenerative diseases such as Alzheimer’s.”

Another issue is that all of this can create an unhealthy feedback loop. “Because of the complex physiological nature of the stress response, we often experience a range of changes in the body,” says Dr Jo Daniels, a senior lecturer in psychology at the University of Bath. “This in itself can become alarming for some people: why is my heart beating so fast? This can then trigger increased attention to what are essentially normal bodily variations, which effectively amplifies those physiological sensations, adding another layer of stress and anxiety.

“When we’re in a stress response, we’re hypervigilant, so we’re more likely to consider normal variations in our bodily sensations to be threatening – and because we are flooded with stress hormones and we are using that ancient part of our brains that is programmed for survival, our decision-making is also likely to be impaired, so we might respond in ways that are unhelpful.”

“If you’re feeling a little on edge, for instance, perhaps you won’t go out, because it feels like your body is saying, ‘Something’s going on here that we need to protect ourselves against’.”

How badly stressed – and how frequently – do you have to be for all of this to be a concern? This is a question scientists are still working on. “It’s an elastic system – it’s designed to respond and recover,” says Vedhara. “How bad is it genuinely? It’s certainly true that the experience of stress has such wide-ranging effects on our physiology that there is potential for it to take a very real toll on our health and wellbeing – but that’s only true for long-term and enduring stressors.”

One near certainty is that more challenging lifestyle factors make stress more of a threat. In a landmark study in the 90s, for instance, researchers recruited almost 400 healthy volunteers, exposed them to the common cold and found that being stressed was heavily correlated with a tendency to become ill. Older adults, dealing with an immune system that’s already declining, might see worse effects from being chronically stressed than people in middle age. But a complicating factor is that we seem to differ hugely in our ability to tolerate stress. “A lot depends on your life experiences,” says Daniels. “People who have been affected by trauma might have a lower threshold for stress response – while other people seem to seek out stressful careers and thrive in them. It is also influenced by learned resilience and ability to manage and respond to stress – though over the long term, as we saw during the Covid-19 pandemic, everyone has their limit.”

So what can you do to get better at managing stress? One of the most evidence-backed options, perhaps surprisingly, really is learning to just stop, take a moment and slow your breathing. “When people are stressed or anxious, they tend to breathe in a more shallow and rapid way, which reinforces the threat response, keeping the physiological loop going,” says Daniels. “If you breathe slowly, you’re giving your brain the message that everything is OK, you are safe – essentially inducing the relaxation response. So something as simple as regulated breathing really can make a difference and head stress off at the pass. The same is true for exercise, which can help reduce the excess adrenaline buildup caused by high-stress responses.”

It’s important to understand that this is most useful in acute (ie, temporary) stress situations – serious and disabling stress can’t be solved by just having a breather. If the stress is more prolonged and frequent, another option is evidence-based psychological therapies including cognitive behavioural therapy (CBT). “When stressed and overwhelmed, we often jump to thoughts like, ‘I can’t cope with this,’” says Daniels. “But is this true? Thoughts are not facts. A helpful strategy can be to sit down and assess the evidence – have you coped before? And with worse? Can you survive the worst-case scenario if you are late for school drop-off and forgot to feed the cat? It can also be useful to stop or phase out coping strategies that aren’t helpful and contribute to the problem – for example, some people tend to work longer or harder to try to solve a work-related problem, which is likely to contribute to increased stress over time.”

With mindfulness-based stress reduction techniques, the focus is different: you’re taught skills to enable you to step back from unhelpful thoughts rather than challenge them.

One option is to experiment with both, depending on the nature of what it is that’s stressing you out: negative thinking patterns and unhelpful coping strategies are often best tackled with CBT, while mindfulness-based stress reduction might be better for coping with the unavoidable.

Avoiding stress completely, of course, isn’t a realistic option. Even the 6% of people in the UK who say they’re never stressed are probably just better able to manage challenging situations than the rest of us. The best thing to do, if you’re concerned that you are suffering from high levels of stress all the time, is to understand and address the things that are causing it: this might be as simple as not going on social media first thing in the morning, or as difficult as changing your job or having difficult conversations with your family.

“Catch your stress response early, and you have a good chance of reversing it using simpler strategies – but for chronic stress, modifications to lifestyle, accessing social support and developing helpful coping skills are key,” says Daniels. “I would suggest people seek help when they are experiencing stress most or all of the time, or if they themselves are concerned about their stress levels.” And remember: while you can’t always control the mammoths charging at you, you can control how you respond to them.