Daniel Lieberman: Evolutionary biologist and professor at Harvard University; author of Exercised and The Story of the Human Body, known for studying how humans evolved to move and how that relates to modern health and disease.
What this episode covers
Daniel Lieberman explains evolutionary medicine: that humans evolved to be physically active only when it is necessary or rewarding, which is why exercise feels unnatural in our comfortable modern world. He debunks myths around the need for 8 hours of sleep, 10,000 steps, sitting being 'the new smoking', and running ruining your knees. He details how physical activity slows senescence, regulates inflammation via muscle-produced IL-6, and lowers risk of cancers, diabetes and dementia. He stresses prevention over treatment, the importance of strength training with age, and barefoot/forefoot running mechanics. He closes by arguing the key to becoming an exerciser is social accountability and compassion rather than shaming.
Recommended on this episode
Vivobarefoot shoes
Vivobarefoot
“there's a Vivo barefoot. Um yeah, I I wear the same shoes... great shoes. Yeah, those are wonderful shoes... exactly the kind of shoes that will help strengthen your feet”— Daniel Lieberman
The guest's own work
Exercised
Daniel Lieberman
“And I recommend everyone to go get this book Exercised because um yeah, I thought I knew a lot about exercise”— Steven Bartlett
The Story of the Human Body
Daniel Lieberman
“In your first book in 2013, The Story of the Human Body, in chapter 12 you said um you used this phrase, you use it or lose it”— Steven Bartlett
Also referenced (named, not recommended)
The Biggest Loser
NBC
“Have you ever seen the TV show The Biggest Loser? Uh, yes, where they where people go and lose weight.”— Daniel Lieberman
Big reveals from this episode
- The idea that humans naturally need 8 hours of sleep is a myth; people without electricity sleep 6-7 hours and the lowest-mortality point is around 7 hours.
- The Paffenbarger Harvard alumni study showed exercise becomes MORE important for survival as you age, with active older alumni having 50% lower death rates.
- Women who get 150 minutes of physical activity a week have 30-50% lower lifetime breast cancer risk.
- Muscles act as an endocrine organ, producing IL-6 which at high levels is anti-inflammatory, so exercise turns down systemic inflammation.
- Running does NOT cause knee arthritis; if anything it may be slightly protective because cartilage benefits from use.
- Low-dose exercise (150 min/week) burns too few calories to drive weight loss, but exercise is highly effective at preventing weight regain after dieting.
- Lieberman's research suggests the biggest driver of becoming a lifelong exerciser is social accountability, not willpower alone.
Worth remembering
- Among the Tarahumara, the concept of 'training' doesn't even exist as a word in their language.
- The 10,000 steps goal originated from a 1960s Japanese pedometer marketing decision, not science.
- Humans and orcas are essentially the only species that live ~20 years past reproduction, evolving to be active grandparents.
- Hunter-gatherers walk an average of about 15 km (two to three hours) per day.
- The Bjorn Borg sports company in Sweden requires every employee to exercise during a mandatory 'sports hour' every Friday.
- Plantar fasciitis is a 'mismatch disease' caused by weak feet encased in stiff, supportive shoes.
- An efficient running cadence is about 170-180 steps per minute, with the shin vertical at landing to avoid overstriding.
- A San Francisco friend used stickk.com to send $50 to the NRA (which she hates) every time she skips her daily walk as accountability.
- Only 50% of Americans ever exercise, and only 20% meet minimal WHO activity standards.