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According to some, we're in the grip of an 'anxiety epidemic', with 2 in 5 of us experiencing work-related anxiety, and up to 1 in 10 of us expected to be affected by a full-blown anxiety disorder. With anxiety capable of wreaking such havoc on our emotional, physical and social wellbeing, you'd be forgiven for dismissing it as a 'useless' emotion. So why have we evolved to feel anxious, and can it still benefit us today?

Experts believe that the 'fight or flight' state induced by anxiety evolved as a means to cope with immediate, short-term fears associated with avoiding predators and securing food, drink and shelter. Once these issues were resolved, the symptoms of anxiety would dissipate. Today, however, the immediate resolution of our worries is often impossible. The result? Chronic anxiety.

According to experts, human society has shifted from an 'immediate return environment', in which actions rendered instant results, to a 'delayed return environment', in which the results of most of our actions take much longer to become apparent (e.g. we work today in order to be paid weeks or months later, and go on dates in the hopes of developing long-term relationships). In evolutionary terms, this shift occurred relatively recently (i.e. within the past few hundred years) - meaning that the mechanisms which served us so well over previous millennia haven't had a chance to catch up. You could argue, then, that much modern anxiety is, indeed, futile and counterproductive.

But a little anxiety, channelled in the right way, could still be a good thing. According to scientists, we should all be striving to hit our stress 'sweet spot'. Although high levels can be detrimental, in small doses, anxiety can help us with all manner of things, from public speaking to card games. Here are seven surprising benefits of feeling anxious...

1. It's a warning sign

Like other negative emotions, anxiety acts as an inbuilt alarm bell, urging and preparing you to take action to alter your current situation. It may not be possible to avoid or resolve every issue which causes you anxiety (after all, those bills still need to be paid), but it is always possible to channel your anxious feelings into some kind of positive action.

Become a 'healthy neurotic' by translating your fears into practical action, psychologists urge. Take things one step at a time to avoid becoming overwhelmed, and start by carrying out one action each day with both an immediate and delayed return. For example, if you are concerned about losing weight for a special event, make a point of taking a 20 minute walk or cooking a healthy meal.

2. It enhances physical performance

That 'fight or flight' response primes you for physical activity, firing up your reflexes and enhancing athletic performance. You might not be a professional athlete, but exercise can often relieve the symptoms of anxiety - make it a regular part of your routine and it could change your body's response to stress for good. There's no need to sweat it out in the gym - go for a run, give yoga a go or try out a dance class. 3. It makes you smarter

There's a raft of evidence to link anxiety with intelligence and enhanced cognitive performance. A little pre-test anxiety is associated with better performance on tricky mental tasks. More intelligent people tend to be more anxious, and produce more noradrenaline (associated with anxiety) in response to difficult problems. Even the accumulation of stressful life experiences appears to make us cleverer! According to Professor Ian Robertson of Trinity College Dublin, it's all down to noradrenaline's ability to enhance focus. Moderate stress "jizzes up" the brain, he says. 4. It can help with public speaking

See that pre-presentation anxiety as your friend and your public speaking skills could benefit, according to science. Research participants told to state, "I am excited," delivered better presentations than those who declared, "I am calm". Don't attempt to eradicate your nerves: reinterpret and channel them. 5. It makes you more observant

Anxiety makes us quicker to spot threats and more alert to relevant information in general. In gambling tasks, anxiety is associated with an enhanced ability to keep track of the relative risks and benefits associated with two decks of cards. Anxious people also seem to be better at spotting liars, leading researchers to describe them as 'natural sentinels'. 6. It makes you a better decision maker

When we feel anxious, we're less likely to think lazily or rely on cognitive biases, making us more objective reasoners. Couple that with an enhanced ability to spot and focus on relevant details, and you can consider your decision making abilities turbocharged. 7. It could save your life

Anxiety-prone people are less likely to be involved in fatal accidents, according to research.