Human beings are not built to endure prolonged periods of stress. If you want to see an extreme example of what it can do to a person, observe prime ministers as they enter and exit Downing Street. Before, fresh-faced, they simper for the cameras. Afterwards, they are gaunt, grey and lined. It is like watching an accelerated version of ageing, and a reminder of how stress corrodes the human body.

We live in stressful times, though. More people are scratching a living in the gig economy, without paid leave or long-term job security. Austerity has ripped through communities like bullets through plasterboard, destroying the mental health of those forced into dehumanising encounters with the machinery of the welfare state. The Amazon is burning, a no-deal Brexit is looming and we are hurtling headfirst towards climate catastrophe. It is no wonder that our mental health services are in crisis, more young people are seeking help for anxiety and schoolchildren are being taught mindfulness to cope with the stresses of social media. According to a 2018 study, 75% of Britons experienced such profound stress in the previous year that they felt unable to cope.

The fact is, stress kills. Prolonged stress has been linked to heart disease, depression and diabetes. But how can you stay healthy when you are stressed? We asked some experts.

Eat well

The salty-sweet smack of snack foods is often the only thing that gets many of us through stressful times. But the crisps you inhale as a deadline looms will make you feel rotten in the long term.

“When we’re overwhelmed, it’s easy to reach for a quick fix in the form of sugar-rich food and drink,” says Azmina Govindji, a registered dietitian and a member of the British Dietetic Association. “This gives you an instant spike in serotonin, the body’s feelgood chemical, but it won’t last – and neither will the fast rise in your blood glucose levels, which also gives you a temporary high.” Instead, opt for complex carbohydrates such as porridge or wholegrain bread, which will give you the energy you need to face a difficult day.

Taking 10 minutes to eat lunch away from your desk will reduce stress levels and prevent unhealthy snacking. “Eat mindfully,” Govindji urges. “Get away from your desk, chew your food slowly and savour the flavours.”

According to research from the American Psychological Association, a third of Americans reach for high-fat, high-calorie foods when stressed. “To avoid this, plan your meals to give you structure and control.” It is unrealistic to expect people to meal-prep during periods of high stress, but a very easy meal plan of porridge and berries for breakfast, a wholegrain sandwich for lunch and vegetable pasta or fish with potatoes and broccoli for dinner is achievable and healthy.

Porridge and berries can help set you up for a long day. Photograph: Arx0nt/Getty Images

Exercise helps

Many of us are guilty of an all-or-nothing mentality when it comes to fitness. We hammer the gym hard before a holiday, but when life gets in the way, our fitness goes out of the window. However, exercise is a powerful natural stress-reliever that will flood your body with feelgood endorphins.

To motivate yourself, the personal trainer Maiken Skoie Brustad advises you to “remember how good you feel after you train. After exercise, you’ll always feel better.”

If you can’t afford to visit a gym, or have responsibilities that keep you at home, there are plenty of free home-based workouts that can be squeezed into a few minutes. “Write down a cardio circuit of five exercises – three high-intensity exercises, such as running on the spot or squat jumps, and then two ab exercises such as planks or crunches – stick a timer on for 45 seconds and do each exercise for two rounds.”

Don’t feel guilty about taking time out to exercise. “You have to be strict with yourself,” Brustad says. “Say: ‘OK, on Tuesday I will clear an hour out of my schedule,’ and train no matter what. When you’re training, focus on why you’re there. It shouldn’t be a treat to give yourself time to train. It should be a necessary thing for healthy human beings.”

Don’t be afraid to seek professional help

It is not normal to exist in a state of perpetual stress. If you feel you are approaching burnout, your first port of call should be your GP. “We all have stress in our lives,” says Dr Zoe Norris, a GP, “but the definition of anxiety as a disease is different from stress.” If patients come to her complaining of stress, she will ask them whether they have been having palpitations, panic attacks or long-term sleep disturbances. These could all indicatebe indicators that they were struggling with an anxiety disorder.

Even if your stress does not meet the clinical threshold for an anxiety disorder, it is a good idea to be mindful of your stress levels. “Almost every part of the body is affected by experiencing constant stress,” Norris warns. “We are not designed for it as humans.”

Develop coping mechanisms. “Put into place protective factors to reduce the impact stress is having on you,” Norris says. Exercise, reading or socialising with friends are all levellers. “If you don’t have these coping mechanisms, what happens is that you develop bad coping mechanisms, such as drinking coffee to stay awake, then wine to help you sleep.”

Some stress is unavoidable: a relative dying, for instance. But if your stress is work-related, Norris encourages her patients to speak to their boss. “If their employers aren’t accommodating, they may come to the conclusion they need to find somewhere else to work.”

Stress is a trigger for self-destructive behaviour, such as smoking or drinking too much. “Lots of patients are keen on detoxes or Dry January, but sustained lifestyle changes are better in the long term.”

Exercise will flood your body with feelgood endorphins. Photograph: Uwe Krejci/Getty Images

Try to get enough sleep

When you are stressed, your sleep often suffers. But staying up late in order to tackle a growing to-do list is counterproductive. “If you are suffering from poor sleep, that will make your stress levels higher,” says Dr Guy Leschziner, a neurologist and the author of The Nocturnal Brain. “Getting as much sleep as possible when you’re feeling overwhelmed will help to manage your stress.”

What about sleeping pills? “They’re a double-edged sword,” Leschziner says. He explains that they can be helpful as a short-term solution, when someone is under acute stress. “If your GP prescribes you a short course of sleeping tablets, for a maximum of two weeks, they can be helpful. People can get to a crunch point where they don’t sleep at all and they can end up in a nervous breakdown situation.” But you can’t rely on pills as a long-term solution to stress. “It’s easy to get on a slippery slope. It’s better to resolve your sleep issues by dealing with the underlying source of stress.” Cognitive behavioural therapy can also help address your anxiety and improve the quality of your sleep.

Get smart about how you cope

“If you feel overwhelmed, it’s usually a combination of work and home-life factors,” says Andrew Kinder, an occupational psychologist and a member of the British Association for Counselling and Psychotherapy.

Develop your support structures. “Look at your relationships,” says Kinder. “Who are your potential allies? It may be family or friends. When people open up, they’re often overwhelmed by how much support is available to them.”

Problem-solving approaches will mitigate extreme stress. If you are worried about debt, for example, tackle it head-on. “Get out the brown envelopes, open them up, start talking with your creditor and negotiate. That will give you more hope than just sitting on it and knowing that it’s festering in the background.”

Remember: your job does not define you

We live in a society that fetishises overwork, whether it is the side hustle you balance on top of your full-time job or the toxic culture of presenteeism that increasingly blights British offices. “Ask yourself the question: what do you really care about?” suggests Prof Josh Cohen, the author of Not Working: Why We Have to Stop.

Strip your workload down to the essentials. “Excessive workloads are one of the main sources of stress,” Cohen says. Many things that we do in the workplace to endear ourselves to our bosses or appear more proactive than our colleagues are basically pointless. “There’s so much that’s just window dressing, where you’re being seen to do something.” Stop doing that and your stress levels may reduce.

To avoid burnout, remember you don’t have to spend every hour in productive or fruitful labour. Sometimes, it is good to just do nothing at all. “Resist a permanent state of task orientation. There are other dimensions of life, and selfhood, that are worth believing in. Reducing yourself to the sum of what you do and identifying yourself so fully with your work won’t do your work any good in the long term. You’ll just end up resenting it.”