Not only does exercise improve your mood and enhance your self esteem, your brain loves physical exercise too. Exercise is now thought to promote the growth of new brain cells. Until recently, received wisdom had it that we are born with a full complement of neurons (brain cells) and produce no new ones during our lifetime. Fred Gage from the Salk Institute in La Jolla, California, broke that myth in 2000 when he showed that even adults can grow new brain cells. He also found that exercise is one of the best ways to achieve this.
Angela Balding from the University of Exeter, UK, found that schoolchildren who exercise three or four times a week get higher than average exam grades at age 10 or 11. The effect is strongest in boys, and while Balding admits that the link may not be causal, she suggests that aerobic exercise may boost mental powers by getting extra oxygen to your energy-guzzling brain.
Simply walking sedately for half an hour three times a week can improve abilities such as learning, memory and concentration. Senior citizens too who walk regularly perform better on memory tests than their sedentary peers. What's more, over several years their scores on a variety of cognitive tests show far less decline than those of non-walkers. Every extra mile a week has measurable benefits - on your thinking abilities and your physique.
In mice, at least, the brain-building effects of exercise are strongest in the hippocampus, which is involved with learning and memory. This also happens to be the brain region that is damaged by elevated levels of the stress hormone cortisol. So if you are feeling frazzled, it may do your brain a favour if you go for a run - or simply take a walk!
Brain storm - if you don't use these skills you lose these skills!
Some parts of the brain are still developing through adolescence (which we now know lasts until well into our twenties!) and it would seem rewires or reorganizes itself at this age. Could this explain some of teenagers' unique behavioural traits?
Prefrontal cortex The prefrontal cortex is the home of "executive" functioning, high-level thinking processes that, among other things, allow us to develop detailed plans, execute them, and block irrelevant actions. This area undergoes a bulking up between the ages of 10 and 12, followed by a dramatic decline. So…if you don't use these skills you lose these skills! If the adolescent's brain is still learning these skills, this might help explain why teenagers can sometimes seem so disorganised, irrational, poor at assessing risk and can't foresee consequences.
Corpus callosum These are nerve fibres linking the left and right sides of the brain. The parts thought to be involved in language learning undergo high growth rates before and during puberty, but this growth then slows. This might help explain why the ability to learn new languages declines rapidly after the age of 12, and certainly is involved in learning writing skills.
Pineal gland The pineal gland produces the hormone melatonin, levels of which rise in the evening, signalling to the body that it is time to sleep. During adolescence melatonin peaks later in the day than in children or adults. This could be why teenagers tend to be so fond of late nights and morning lie-ins. It is possible teenagers' 8am school starts may be a mistake. They may take less in for the first two lessons of school as they are still in biological 'sleep time'!
Right ventral striatum This area of the brain is thought to be involved in motivating reward-seeking behaviour. A study last year showed that teenagers had less activity than adults in this part of the brain during a reward-based gambling game. The researchers speculate that teens may be driven to risky but potentially high-reward behaviours such as shoplifting and drug-taking because this area is under-active.