The human brain is an amazing machine which sometimes doesn't work as brilliantly as we would like, writes Nicola Morgan.

When we desperately want it to work at its best - exams and tests for example - many factors affect whether our brain has a good day or not. Some of those factors we can't control - things like being ill, or receiving bad news - but many we can control, once we've learnt how.

The exam season puts a lot of pressure on you and your brain. Exams are often close together and the stakes are high. It can be hard to plan far enough ahead and scary if you feel you haven't. You want to do your best but sometimes it's hard to see how you can make that happen. Some lucky people seem to thrive in these conditions but most people welcome any advice to make it all feel less out of control.

So, imagine you're an athlete, preparing for a major competition. Your coach will help you work on all aspects of your life: nutrition, sleep, stress levels and mental state, as well as practising the actual sport. Coaches will be very scientific, using the most up-to-date research about performance. As you prepare for exams, it's a good idea to have the same attitude, working on both body and mind, so that they can produce peak performance on the day.

The first thing to know is that our brains become good at things by creating strong networks between cells in the brain called neurons. And this happens mainly when we practise. Each time we do something, the connections between neurons become that little bit stronger so that the next time it's slightly easier. In theory… But there are conditions which alter how effective that practice is. The conditions include nutrition, sleep, mood, attitude, confidence and self-esteem but the one I want to talk about is stress.

Stress is healthy and important: the body's natural response to a threat or challenge, producing chemicals (especially adrenaline and cortisol) to make blood rush to our heart, brain and muscles and make us focus acutely on what needs to be done. It is designed to produce peak performance in times of danger, threat or need. And that works well for exams.

This chemical reaction also makes us feel physically uncomfortable. You know that feeling before a race, test, interview, public performance, even just speaking in front of the class: you're tense and jittery; you might feel sick; you might be irritable. Those symptoms are a perfectly normal part of this chemical reaction. If we felt too comfortable, we probably wouldn't get up off the sofa!

When the reason for stress passes, and we've dealt with whatever it is, those adrenaline and cortisol levels drop and we feel better. But the problem with lots of modern stresses (including what you deal with at school and in your friendship groups and including in the long lead-up to exams) is that they are regular and frequent, a drip-drip effect, giving us no chance to recover in between. So the cortisol builds up in our body and that can lead to headaches, stomachaches, poor concentration, poor mood and sleep problems. And more.

Stress affects learning. A bit of stress improves it but too much can make it harder to learn. Parts of your brain might be occupied with worries or other things you're thinking about, leaving less "brainpower" for your work.

So, learning to manage stress levels, building relaxation into every day, for example with exercise, social time and reading for pleasure, will help stop the cortisol build-up. Getting control of your stress will improve mood, confidence and concentration. It will help you learn more easily, recall facts more effectively, and perform better on the day of each exam.

The more we all understand about what affects our brains, positively and negatively, the better we can control them, feel better and perform at our best. We can't control everything, but we can make a huge difference. Focus on the things you can control!

Nicola Morgan is an award-winning writer for teenagers and the author of Blame My Brain and The Teenage Guide to Stress. She offers training on aspects of adolescence and has created Brain Sticks™, teaching resources about the brain and mental health.

Nicola is proud to be a co-author the new National 5 & Higher Study Skills book coming from Leckie & Leckie in August. Priced £4.99. ISBN 97800081135313. Available to buy online and in all good bookshops. www.nicolamorgan.com

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