Without stress, we wouldn't have got where we are today. Our cave-dwelling ancestors would have perished at the hands of bigger-toothed beings if our bodies had not been designed to secrete energy-boosting stress hormones that warn us of danger.
Now, the average person who doesn't need to wrestle a rival for a lunch or take flight from a wild animal still utilises stress to meet day-to-day challenges, but too much can have a negative effect. The hormones associated with stress - cortisol, adrenaline, norepinephrine - are beneficial in small doses but can be difficult to control and harmful to the way our bodies work.
COMMON CAUSES OF STRESS & HOW TO AVOID THEM
"Do what you love and you'll never work a day in your life." The old saying makes it seem so simple, but many people choose their career path as teenagers - a time when frankly you have more pressing matters to attend to. Being unhappy at work can make you feel like you're wasting the best hours of the day, but things can change...
Jenny Ungless, the founder and director of City Life Coaching, says many people in their late 20s and throughout their 30s successfully change careers. Often they "fell into" their current role in their teens or after university, and then they're overcome with the realisation,"This isn't really what I want to do and I've got 30-plus years left doing it."
"People hit a certain point where the current stress they're experiencing in an unsatisfying career means it makes more sense to cut their losses and move on."
Ungless, who has most recently helped turn a marketeer into a nutritionist and an IT manager into a counsellor, says that approaching 30 makes many people assess what really makes them happy and that can lead to swapping stressful, high-powered roles for lower-paid - but ultimately more fulfilling - positions.
Every so often, an elderly couple hits the news with their decision to end decades of married life because one of them can't abide the other squeezing the toothpaste tube in the middle, or not being able to make a proper cup of tea. While their problems must run far deeper than such ridiculous peeves, tiny issues can turn gargantuan over time if they're left to fester.
Dr. Sheri Jacobson, Psychotherapist & Clinical Director at Harley Therapy, said the primary causes of couples’ stress are sex, money and families.
Sex: As well as issues brought on by physical sexual problems, couples with mismatching levels of desire, or preferences, often find it stressful to discuss with their partner, which Jacobson says can lead to "outright arguments or latent frustration."
Money: On top of general money pressures, sometimes partners clash over how money should be made (how much to work) and how it should be spent (whether to save or take out loans). "Some partners keep the issues hidden, which compounds the problem as it can breed mistrust."
Families: The most common causes of family stress for couples is over how much time should be spent with extended family and how to blend step-families. "We chose our partner but their family - and to some extent their friends - may not be people we would chose to spend time with."
No one likes talking about the purple stuff but money is a major cause of stress. Cavernous debts batter away at mental wellbeing and so many people suffer from money-related stress the NHS launched a dedicated helpline to try and tackle the problem.
"It's common for people to find themselves in a downward spiral, says Caroline Keegan, Chartered Financial Planner at Serenity. "They think: 'I owe money, I am depressed, I have no control over my life...so I'll buy something new to cheer myself up,' then they owe more money..."
4. NUTRITIONAL HEALTH
Sticking the kettle on for a nice cup of tea is a typical response to stressful situations, but as well as a calming camomile or faithful English Breakfast, certain foods can aggravate anxiety levels while others help calm the nervous system and alleviate stress.
Dora Walsh, Head Nutritionist and founder of Nutriheal, says many lifestyles contribute to diminishing the body's stress-easing B vitamins.
"I've seen countless clients suffering from stress and found the B vitamins always help calm a jittery nervous system. Many people are deficient - especially heavy coffee and alcohol drinkers - so I ask them to cut down as much as they can and increase vitamin B rich foods in their diet, such as oat porridge, spelt bread and brown rice."
Binning off that jog for an evening of Broadchurch on series link will probably elevate your mood in the short term, but there's no denying regular exercise is a mood enhancer that lowers stress by rewarding sweat with feel-good endorphins.
Faisal Abdalla, a trainer at Barry's Bootcamp London, says new clients who are unused to exercise find themselves less stressed as weeks go on.
"They're busy people and when I see them in the evenings, the weight of their day has weakened them. Exercise gives an inner strength, as well as a physical workout because endorphins increase Positive Mental Attitude (PMA). They're forced to forget all their worries for a while - and of course everyone's spirits are lifted by seeing the beneficial physical effects on their body."
While small amounts of stress can spring us into action, no good can come of unleashing your inner Hulk just because you've been jostled on the crowded morning commute.
Dr. Sheri Jacobson says, "There is a very clear connection between stress and anger. When we are disproportionately stressed at a given time, or when stress accumulates over an extended period, the excess of adrenaline, cortisol, can manifest in a number of symptoms, including palpitations, skin problems, sleep disturbances, loss of libido and appetite; as well as irritability and anger.
She says that anger often arises when we are overwhelmed and our own self-imposed rules, such as, 'I must be perfect' or 'Others must always be respectful to me', are not adhered to.
Caffeine can add pizazz to a dreary morning, cigarettes may soothe the midday rush and wine often helps us unwind - and it's hardly Trainspotting fodder. However, dependancy on our temporary stress-soothers can lead to long-term problems.
Deborah Marshall-Warren, a hypnotherapist and relaxation specialist says, "Sometimes dependency on seemingly harmless substances can be a kind of self-harming behaviour so if you do decide to kick an addictive habit it's important to do so lovingly and not beat yourself up. The mind needs care and understanding to respond in kind."
The husky, ear-soothing tones of Honor Blackman or Mariella Frostrup convey a calm confidence, but for those who have not been blessed with such an admirable voice box, fears about speaking in public can be stressful - especially in professional situations.
Voice Coach Rachel Coffey says concerns about speaking and voice are a surprisingly common cause of stress that impacts negatively on people's everyday lives, professionally and personally.
"Before coming to me some of my clients were foregoing big promotions, dodging key client meetings or even skipping a friend's wedding for fear of speaking in public or having to chat to people they don't know."
By Anna Pollitt. Images: Rex Features
15 EASY ACTIVITIES TO KEEP STRESS AT BAY...
Stroke a dog
Scientists have long been telling us that pets enhance our wellbeing, with Belfast University research singling out dogs as the feel-good heroes of the pet world as they help people fight depression and socialise more.
No room for a pooch and petted all the ones in the local park?Emerald Street hit on a dog-borrowing service.
Channel your inner Emin
Utilise stress by pouring your energy into a creative activity - whether it's learning how to write a soap script or creating a powerful painting for your home. Browse national course finder Hot Courses for your nearest classes.
Read a book for six minutes
Delving into a good book for just six minutes can reduce feelings of stress by up to 68% according to University of Sussex research. Take a look at Stylist's hot picks for April.
Whether it's a hardcore sports or a soothing spa rub, massage has been scientifically linked to reduced levels of the stress hormone cortisol and an increase in immune-boosting white blood cells.
Do a Sarah Beeny
Flick onto any of Channel 4's numerous property shows to see the common theme is streamlined, tidy surroundings. A huge UCLA study recently showed many US families are overwhelmed by clutter, and managing the volume of their possessions elevates levels of stress hormones in the occupants.
Reach new mental heights
Tell Dear Diary
Unravel your mind on paper, Bridget Jones and Adrian Mole style, to help de-stress - and have something to laugh about in years to come.
Everyone should have something to look forward to, so if July is looking a little dry, stick a pin in it and start organising something spontaneous and fun for the date you land on.
Ally Sheedy's Breakfast Club Alice band makeover might have gone a tad too far, but investing in our appearance - whether it's a ten-minute face mask or a brightening nail varnish - is a quick and effective way to feel good. See Stylist's Daily Beauty Bulletin for inspiration.
Get out more
Londoners may have to scout around for some green space, but it's well worth it according to a study published in the British Journal of Sports Medicine, which found participants became less frustrated and more meditative than when they were wading through city streets.
Make that daft forwarded email a priority - laughter is one of the most powerful stress-relievers, with beneficial short and long-term physical and mental effects.
Cry it out
It's better out than in. As well as unleashing emotions, some studies suggest that tears held secrete stress hormones from the body.
See your doctor
Got a nagging medical worry that you've been too busy to deal with? Invest in some peace of mind by registering with a nearby GP and book an appointment to discuss it.
Download new music
Does a browse around iTunes give you sweaty palms? If so, new findings by McGill University could explain why.
Researchers found that the sounds of pleasing new music rewards the brain's 'pleasure centre' in a similar way to good sex.
Have a natter
Calling family or friends who you don't speak to as often as you'd like is a two-pronged stress reliever - you feel better for getting in touch and catching-up on someone else's life is like a breath of fresh air in your routine.