Use It or Lose It
Physical activity slows senescence, so activity must go up with age, not down - and retirement is the trap.
- Difficulty
- Moderate
- Time to result
- ~ongoing to results
- Steps
- 5
- Confidence
- 90%
Lieberman identifies the belief that it is normal to be less active as you get older as the single most important myth about exercise. Ageing is the clock ticking, which nothing changes; senescence is how the body degrades, and physical activity slows it. Movement turns on repair and maintenance processes that keep muscle strong, limit DNA mutations, maintain mitochondrial numbers, and clear the gunk from brain cells that contributes to Alzheimer's and other dementias. Humans are one of the very few species that live roughly 20 years past reproduction, and ancestrally those grandparent decades were spent working, foraging and caring for grandchildren - not resting. The prescription is that as you age you must deliberately maintain and add activity, particularly resistance training, and that if you retire from work you must replace the physical activity that work supplied.
Origin
Lieberman set out the use-it-or-lose-it principle in chapter 12 of his 2013 book The Story of the Human Body, and the ageing case is sharpened by Ralph Paffenbarger's long-running study of Harvard alumni, which Lieberman calls one of his favourite studies ever published.
Core principles
- 01Ageing is unavoidable; senescence is partly negotiable.
- 02Physical activity does not merely maintain the body, it activates repair and maintenance across nearly every system.
- 03Exercise becomes more important with age, not less.
- 04Loss of muscle - sarcopenia - triggers a self-reinforcing decline into frailty and further inactivity.
- 05We evolved to be working grandparents, not resting ones.
- 06Retirement is a modern Western invention, and there is a physiological price for it.
- 07It is the absence of physical activity, rather than age itself, that lets ageing run amok.
How to run it
- 1
Reject the default that activity should taper with age
Treat declining activity as a choice being made, not a natural consequence of getting older. Lieberman calls this the most important myth in the field by far.
Watch out Medical training reinforces the default - students are still taught that blood pressure simply goes up as people age, which Lieberman says is a feature of inactive Western populations rather than of ageing.
- 2
Add resistance training, at least twice a week
Deliberately schedule strength work even if, like Lieberman, you have always preferred endurance activity and disliked weights. He now does a good two strength workouts every week at least, specifically because of what he learned about ageing.
Pro tip Endurance and resistance work slow different components of senescence, so neither substitutes for the other.
Watch out People default to the training they enjoy because they get reinforcement from it, which is exactly how a lifelong endurance athlete arrives at old age with no strength base.
- 3
Protect against sarcopenia before it starts the spiral
Muscle loss produces frailty and reduced functional capacity, which reduces activity, which accelerates further muscle loss. Intervene while the loop is still open rather than after it has closed.
Watch out Once the vicious cycle begins, it is described as genuinely debilitating and much harder to reverse than to prevent.
- 4
If you retire, replace the activity work supplied
Retirement removes a large block of daily movement along with the job. Lieberman's position is that you can absolutely replace work with challenging, rewarding, fun things to do - the important thing is simply not to stop being physically active.
Pro tip Choose replacements with a social and structural component, since the workplace was supplying both the necessity and the community.
Watch out Bereavement compounds the effect: grief and depression raise cortisol and suppress immunity, and often coincide with a collapse in activity.
- 5
Keep a functional benchmark you refuse to lose
Hold onto a concrete physical capability you intend to still have decades from now - Bartlett's version was being able to walk down 300 metres of stairs at 60 because something worth doing was at the bottom. Train to keep the capability, not an abstract number.
Pro tip A specific, emotionally loaded benchmark survives motivational slumps better than a target weight or pace.
In the wild
Ralph Paffenbarger exploited the fact that Harvard, like other private universities, never loses touch with its alumni because it keeps asking them for money until they die. Through the development office he followed cohorts of alumni for 25 to 30 years, repeatedly surveying physical activity, diet and smoking, then correcting for every factor available. Alumni in their 20s, 30s and 40s who exercised four or five times a week had roughly 20% lower death rates. By the time those alumni reached their 60s and 70s, the more active group had 50% lower death rates.
→ The effect of physical activity on mortality grew larger with age, and the result has since been replicated many times - establishing that exercise becomes more, not less, important as you get older.
Lieberman describes himself as someone who has always loved walking, running and endurance activity and always hated doing weights, calling himself a wimp and not a very strong person. The more he studied resistance training and its importance with age, the more he kicked himself for having been lazy about it.
→ He now does at least two strength workouts every week - the single change from writing the book that stuck in his own life.
Humans evolved to live roughly 20 years past reproduction, a life history almost no other animal shares apart from killer whales. Ancestrally and in many cultures still today, grandparents work in the fields, hunt, gather, provide food for children and grandchildren and help with childcare - their job is to be physically active. That activity switches on repair and maintenance processes across muscle, DNA, mitochondria and brain tissue.
→ Lieberman contrasts this with modern retirement to Florida or Mallorca with golf carts, and concludes that nobody retired in the past and that we pay a price for the modern version.
Common mistakes
Assuming the diseases of ageing are inevitable
Lieberman argues we have confused diseases that become more common with age for diseases caused by age. High blood pressure, many cancers and dementias are substantially preventable, and treating them as fate removes any reason to act.
Blaming genetics for a trajectory that is largely environmental
In Lieberman's field the phrase is that genes load the gun and environment pulls the trigger. Predispositions exist, but the same genes in different environments produced far lower disease rates in previous generations - and environment is partly under your control.
Doing only the training you already enjoy
People do what they like because they get reinforcement from it, which reliably produces a one-sided training history. Lieberman's own decades of avoiding weights is the cautionary case.
Treating retirement as a rest
When people retire they become less active, and that loss of activity has enormous effects across the body, brain and mind. The status change quietly removes the largest structured source of daily movement most people have.
Is it for you?
Best for
People in midlife or later planning how to age, endurance athletes with no strength base, and anyone approaching or newly in retirement.
Not ideal for
Young athletes optimising performance, and anyone with an acute condition where a clinician has specifically restricted loading.
From the transcript
“The most important myth, I think, by far, is this idea that as you get older, it's normal to be less active. And that is…”
“as you get older, exercise becomes more, not less, important for maintaining your health.”
“So now I try to do a good two strength workouts out of every week at least.”
“The important thing is just not to not to stop being physically active.”
“it's the absence of physical activity, which lets aging run amok.”
“when we need when we increase our demand, we increase our capacity, right? When you go to the gym and you work out, right? You…”
From the episode
Harvard Professor: "10,000 Steps A Day" Is A LIE! Revealing The 7 BIG LIES About Exercise, Sleep, Running, Cancer & Sugar!!! Daniel Lieberman
Harvard Professor