New Scientist - The Essential Guides

THE human species was made to move. In recent years, research has overturned many of our assumptions about what exercise does for us, and revealed quite how vital it is to our health and well-being. It is little surprise that physically activity has come to be seen as a wonder drug, essential for the body and mind to function at their best. This wealth of old and new information has led to us being bombarded with advice in the media and from health bodies about exercise, but not all of it is grounded in the latest evidence, or any evidence at all. The aim of this Essential Guide is to cut to the facts about exercise and why it really is the best thing you can do if you want…

It is often said that exercise is the best medicine, and it is true that the benefits to both body and mind are innumerable. If only it could be distilled into pill format and dispatched to everyone. Exactly why exercise is so good for us, and inactivity so bad, however, can be a complicated question to answer – one that goes back deep into our evolutionary past. Understanding why exercise is such a tonic is only the start, though. We then have to ask what is the best dose, and how often we should take this remedy, if we truly are to reap the benefits.…

IT IS a shocking fact that many of us today are almost entirely sedentary. The current US and UK government guidelines for physical activity recommend that adults do at least 2.5 hours of moderate exercise or 75 minutes of vigorous exercise every week. In the US, only half the population meet these guidelines, and the situation is only slightly better in the UK. But to work out whether you are doing enough, you first need to know what counts as moderate and vigorous. Physical activity is any type of movement that uses up energy. So you can think of exercise as a type of physical activity that is done in a structured way and has as its goal some sort of physical fitness – though as we will discover in…

AS A species, humans evolved from lazy stock. All animals rest when they can, saving precious calories for survival and reproduction, but by any measure, our great ape relatives are impressively sedentary, resting and sleeping for 18 hours a day. However, when our ancestors began hunting and gathering, around 2.5 million years ago, it put an evolutionary premium on physical exertion. These activities are incredibly demanding, requiring hours of effort each day to find food. Individuals that were more active found more food and had more offspring – and these, in turn, inherited their desire to move. Over generations, the human brain evolved to reward hard work, releasing endorphins and endocannabinoids – the body’s homemade, feel-good drugs – in response to endurance exercise. The “runner’s high” was born, taking up…

Early humans, we always thought, first struggled onto two feet after a long period of gorilla-like knuckle-walking. But a newer hypothesis suggests that our move to bipedalism began much earlier, at a time when our ancestors were still living in the trees. According to this line of thought, about 15 million years ago, our tree-dwelling ancestors began to spend more time standing up, at first holding onto branches with their hands and gradually balancing independently. One study found that even lightly touching a moving branch with the fingertips provides enough sensory feedback to the brain to stay balanced. If this is true, then learning to balance is an integral part of what made humans what we are today. Turn to page 72 for more on balance…

FIRST, the obvious benefits: exercise keeps our muscles and hearts strong, our blood vessels pliant and improves aerobic fitness. When we get our heart rate up, the stresses imposed by the blood rushing through our arteries promotes the production of nitric oxide, which helps repair blood vessels and keep them elastic. Maintaining strength and aerobic fitness is particularly important as we age. Older adults who can cover at least 365 metres in a standard 6-minute walking test have half the risk of dying in the subsequent decade as their peers who can’t make 290 metres. Additional robust evidence comes from the Exercise is Medicine initiative pioneered by the American College of Sports Medicine in Indianapolis, Indiana. Researchers there have collated studies over decades looking at people who follow the US…