Exercised: The Science of Physical Activity, Rest and Health

by Daniel Lieberman

The premise for this book is a very interesting one. There is a wealth of conflicting information about exercise, nutrition and rest, often taking opposite attitudes and making it difficult to know what the best thing is to do. In this book, Lieberman takes some of the biggest myths about exercise, rest and health and sets out the scientific evidence against those myths.

A Scientific approach

The book gets off to a slow start but settles into the following pattern: what’s the myth or assertion people tend to believe, followed by interesting anecdote or relevant story and then the evidence and arguments for and against.

The questions examined seem legitimate. Asking how much sleep do we need or the assertion that most people don’t get enough sleep is examined and analysed. Often important for these questions, unsurprisingly, is dismantling the debate. In this instance, where did the assertion that we need eight hours of sleep a night originate from? What does the evidence say?

Lieberman is effective at reviewing the evidence, including sufficient evidence at points when you need it and giving balanced takes. This owes to his background as a scientist, and it helps you keep up with the arguments for and against and is compelling. Nor is it overmuch on detail: you have enough to look more deeply into the key points, without having to check the references every two seconds.

So, what is best?

Perhaps the main question readers want answered is well, what should I do? What’s best? Broad spoiler alert: plenty of cardio, some weights, and the importance of maintaining this regimen as you age. Consistency and longevity is more important than the type, the amount of protein you take, the earphones you use, the brand clothing you wear. I’m being facetious, but I like that he considers the modern capitalism on the West, such as in his discussion on sleep:

Even more insidiously, we have become prey to what has been termed the sleep-industrial complex. People stressed about sleep are enticed to spend a fortune on hi-tech mattresses, sound machines, noise-cancelling headphones, light-blocking curtains, gizmos to halt their bedfellow's snoring, eye masks, and something called high performance bedding. These mostly harmless gadgets would no doubt amuse our ancestors who slept on the ground by a fire, but we should be downright alarmed by the abuse of sleeping pills. Sleeping pills, which are highly habit-forming, are a multibillion-dollar industry. Not counting over-the-counter medications, prescriptions for these pills in the United States have more than tripled since 1998.

(pp.92-3, Exercised)

Other advice includes a few of the different types of exercise – running, weightlifting, yoga; endurance, how sitting down affects us, and the importance of exercising at different ages, the effects of exercise on risk for disease and life longevity. Some of the advice is, perhaps, fairly common sense, but this book helps in terms of reviewing what the scientific literature suggests is the right approach to take.

Readability

The book is quite readable, using anecdotes to illustrate points and lead into a topic. The research done on the Hadza, the Tanzanian indigenous ethnic group who are the basis of some of these stories, have popped up in several non-fiction books on the subject lately. Some of the anecdotes are perhaps less interesting, when Lieberman focuses more on general personal experience rather than his deep scientific knowledge, but I’m sure this is a particularly subjective comment.

The inclusion of the anecdotes lightens a difficult subject. As for the more ‘scientific’ writing, there are plenty of complex terms which, for the most part Lieberman breaks down, though there was the occasional unexplained word slipping through which left me looking it up myself.

Final Score

There aren’t too many criticisms of the book. I wasn’t grabbed by all of the anecdotes, and as above I feel Lieberman shines when he’s dissecting the scientific evidence and the assertions people make rather than telling his own personal stories. But more important to this book is considered judgement of the evidence, inclusion of the important socio-cultural themes about exercise, and a set of broad practical recommendations that readers can take away with them.

Exercise is broad, and cultural norms, myths, facts and scientific research often create a hazy picture. But with the approach Lieberman takes, questioning truly why certain assertions have been made, it helps shed light on a complicated subject and is well worth your time if interested in the subject.

8/10