Finally there is the social interaction. If a person is at home feeling depressed, then visiting the gym with other people might provide a break from that isolation. If you use a drug to block the production of beta-endorphins, the improvement in mood after exercise still occurs, suggesting that endorphins might have nothing to do with the process.
In the Department of Kinesiology at University of Wisconsin-Madison there are treadmills, weight machines, exercise bikes, free weights and a swimming pool. While human guinea pigs pump iron every flutter of their heart can be measured. Outside there is even an arboretum where volunteers cut down the undergrowth while wearing transmitters which allow the scientists indoors to measure their heart rates. After they’ve finished the work, their levels of anxiety and depression are measured. With the help of this equipment and a team of volunteers, Professor William Morgan has developed a theory which might explain why exercise can make you feel happy – he calls it the distraction hypothesis. It is appealingly simple; exercise makes us feel good merely because it distracts us from the worries of the day. He found that although people do experience a decrease in anxiety as a result of vigorous physical activity, the effect soon wears off and within twenty-four hours you’re back to where you started. Therefore regular exercise could be a way of topping up your joy and keeping a lid on anxiety. Too much exercise, however, can have the opposite effect. In experiments where swimmers progressively increased their training sessions from 3,000 metres a day to 12,000 metres a day, the athletes gradually became more depressed. Once they began to decrease the distance they swam, their mood slowly returned back to normal.
There is some more good news for people who prefer to sit still. Professor Morgan also found that when he asked people to sit in a quiet room in a comfortable old leather armchair or lazyboy, as he calls it, for the same length of time as an exercise session, they felt just as good afterwards.
A final theory of why exercise might make you feel good is the thermogenic hypothesis – the idea that you feel happy after exercise because your body temperature has increased and that it is this high temperature which is responsible for the release of beta-endorphins, which in turn make you feel good. Not surprisingly, research in this area began in steam baths and saunas in Scandinavia. In one study back in 1972 the volunteers who took part had a twenty-minute sauna followed by a ten-minute shower for which they were paid in cash and in beer. Before and after the sauna the mood of the volunteers was measured. Beforehand two of the twenty male volunteers had warned the experimenters that they didn’t like saunas and indeed four people did find the sauna so stressful that they had to be let out early. However, overall people did feel less anxious after the sauna, but so did the control group who had undressed, sat waiting on a bench for twenty minutes and then had the ten-minute shower.
More recently William Morgan’s team have tried to determine whether it’s the exercise per se or the rise in temperature which makes people feel good after exercise. He found that if the whole body is heated mood can improve for up to twenty-four hours and in the bloodstream at least, levels of beta-endorphins rise. The team have come up with ingenious experiments in an attempt to establish the answer such as getting one group to exercise dressed in everyday fitness gear while another group exercised clad in warm clothes, a hood, gloves, a surgical mask and two blankets. Despite the rise in body temperature, not surprisingly the hot group ended up feeling more anxious than the others, rather than less. Another approach is to prevent the exercise from increasing the body’s temperature by lying in a cold bath for half an hour before exercising. It was found that if a person’s body had been cooled beforehand their temperature remained low and they felt no better after exercise, whereas the people whose bodies had not been cooled did feel happier after exercise, suggesting that it could be the rise in temperature, not the exercise itself, that makes people feel better.
Another way of testing this theory is to prevent body temperature from rising with exercise by doing that exercise under water, but when this was tried with scuba divers they still felt better afterwards, suggesting that it’s not the warmth that’s doing the trick. At the University of California Shawn Youngstedt and his team put volunteers on exercise bikes under water with their heads poking out above the surface. There was no improvement in mood after exercising, but the researchers do warn that this might have been due to the novelty of the task or anxiety caused by having their oesophageal temperature taken – a procedure involving the insertion of a tube up the nose and down into the throat. Other experiments have involved exercising while wearing a scarf filled with ice and even having a rectal temperature taken before, after and (somehow) during exercise. In this study anxiety did decrease after the exercise session, but perhaps the participants were simply relieved that it was over. So it seems that exercise can make people feel good, but we’re still a long way from knowing exactly why.
smiling
‘Cheer up! It might never happen,’ builders like to shout as I walk along the street perfectly happily, not feeling sad, but daydreaming. Irritating though these remarks are, the builders might in fact be on to something. While it makes intuitive sense that exercise might make you feel good, the next topic is more primitive and rather more surprising. Remarkable research has found that we can influence our brain chemistry through something far less taxing than exercise – smiling.
The first person to make a serious study of the smile was the French neurologist Duchenne de Boulogne who determined which muscles were needed to make each facial expression by stimulating each muscle with an electric current. In 1862 he published a book chronicling his findings which included photographs of a man clearly in a state of terror while metal implements were held against his skin. Fortunately for the man, the expression was created purely using the electric current and he could feel no pain because he had a condition which rendered his face numb. Using this method Duchenne studied in detail the muscles responsible for different facial expressions, including smiling. He soon identified the difference between a genuine and a fake smile; the key is a muscle above the eye where crow’s feet form, called the orbicularis oculi. Anyone can fake a smile by raising the corners of their mouth and baring their teeth, but if the muscle above the eye remains motionless the smile looks wooden.
Today the world authority on facial expression is Paul Ekman, who uses his expertise to, amongst other things, train police to spot when people are lying. He’s found that a smile is hard to fake because most people can only voluntarily contract one part of the orbicularis oculi – the inner part which tightens the eyelids. Only 10% of people can decide to contract the outer part of the muscle which pulls the eyebrow down at the same time as raising the cheek and pulling up the skin below the eye. Therefore the way to judge whether a smile is genuine is to see whether the cheeks move higher and the eyebrows tip down slightly. You can experiment by standing in front of a mirror faking smiles. Hopefully you will feel so daft that eventually you smile genuinely and then you can see the difference. Ekman’s other clues to spotting a false smile are that it can be asymmetrical, with a timing that isn’t quite right – either just too early or slightly too late. If the person faking the smile is right-handed, the left-hand side of their mouth will tend to move up more.
The authenticity of a smile can reveal the unexpected. In one study women’s smiles were analysed from a college yearbook. Thirty years on the women with the genuinely happy smiles using the muscle around the eye, were more likely to be married and happy. The researchers did rate each woman’s looks in case the smiley women were simply the prettiest and perhaps therefore the most likely to have found partners, but this wasn’t the case.
It’s not only adults who can fake a smile. Paul Ekman discovered that if a stranger approaches a ten-month-old baby, the baby might well smile, but that smile won’t involve the crucial eye muscle, but if their mother approaches them, it does. Although the baby isn’t deliberately faking a smile, at this young age it can already smile politely.
From the age of four or five weeks babies