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In this podcast episode we speak with Dr. Daniel Lieberman, professor of Biological Sciences at Harvard University, whose influential research has helped popularize the idea that humans are born to run.

His new book is called Exercised -Why Something We Never Evolved to Do is Healthy and Rewarding.

Interview with Daniel Lieberman

Daniel Lieberman is a professor of Biological Sciences at Harvard University. He received his B.A., M.A., and PhD from Harvard and also a M. Phil from Cambridge. One of his focuses is on studying the evolution of physical activity and (lucky for us) the evolution of running.

In 2004 he co-authored a paper that argued that humans evolved to run long distances. His work was influential to the writing of the best-selling book Born to Run by Christopher McDougall. This book argues for barefoot/ minimalism and profiles the Tarahumara -a tribe in Mexico renown for their long distance running ability.

Dr. Lieberman’s new book is called Exercised -Why Something We Never Evolved to Do is Healthy and Rewarding.

Daniel Lieberman. photo credit: The Harvard Gazette

From the Book . . .

Dr. Lieberman argues that we didn’t evolve to exercise. Our ancestors were hunter-gatherers and “spent many hours a day walking, carrying, digging, and occasionally running, climbing, throwing, dancing and fighting.” They didn’t need treadmills and cross-fit boxes.

Exercise is needed by us modern humans because of all of our labor-saving devices -like indoor plumbing. When was the last time you carried a bucket of water? We exercise because our daily existence doesn’t require us to exert our bodies. But before you feel bad for all your inactivity . . .

Hunter-gathers also spend a lot of time relaxing. The Hadza people of Tanzania, considered one of the last hunter-gatherer tribes in Africa, spend an average of nine hours a day sitting.

Feeling less bad about my laziness might be my favorite insight from Exercised. The book’s title is a play on words because the adjectival definition of “exercised” is to be vexed, anxious, worried, harassed.

Dr. Lieberman says it’s time to stop being exercised about exercise. Here’s why:

• Sitting is NOT the new smoking.
• Our hunter-gatherer ancestors didn’t posses super-human stamina that we don’t possess.
• It’s perfectly normal not to feel like exercising, though its health benefits are indisputable.
• Not everyone needs 8 hours of sleep every night.
• You CAN lose weight by walking.
• No, running doesn’t ruin your knees.

There are 12 myths dealt with in the book and the final chapter has a very helpful survey of how exercise helps fight chronic diseases. Take cardiovascular disease for example:

Cardiovascular disease and exercise
“Coronary artery disease is ancient and has even been diagnosed in mummies. But research on nonindustrial populations provides powerful evidence that coronary artery disease and hypertension are largely evolutionary mismatches.”

Amongst sedentary people it’s normal for blood pressure to rise with age. But among hunter gatherer populations (like the San and Hadza) lifelong low blood pressure is normal.

“By the same token, blood pressure can also stay normal into old age among industrialized people who eat sensibly and stay active.”

Cardiovascular disease typically has several intertwined factors including high cholesterol, high blood pressure, and chronic inflammation.

“It is widely recognized that cardio exercise is best for the cardiovascular system. Extended periods of aerobic physical activity require the heart to pump high volumes of blood to every corner of the body, stimulating beneficial responses that keep blood pressure low and the heart strong.”

Shorter durations of high intensity cardio appear to be as good as lengthier doses of low intensity cardio. Lifting weights also has value by improving cholesterol numbers and lowering resting blood pressure.

I hope you enjoy this interview!