Optimal aging: tips from a longevity expert
Takeaways from a Princeton biology professor and author of the book, "How We Age."
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Colleen Murphy, a Princeton professor of molecular biology, has spent more than two decades studying the biological mysteries of aging. She wrote a book, "How We Age: The Science of Longevity," that synthesizes nearly a thousand scientific studies into a practical understanding of human aging and how we can slow it down or, at least, increase our healthy years.
This is not a book review. It’s a list of takeaways.
Below, in concise bullet-point format, are the takeaways not from Murphy’s 2023 book but from four in-depth interviews1 with Murphy about where the science of aging or, as the case may be, anti-aging, is headed. And also practical advice about how we all can increase our chances of living stronger for longer.
(All quotations below are Murphy’s, taken from the four interviews.)
Exercise: the non-negotiable foundation of aging well
Exercise is Murphy's single best advice, more than any current drug or supplement, for aging with all-purpose strength. "If you do nothing else, exercise and sleep, because those are the things that are going to help you no matter what." For sedentary people, just walking daily provides substantial benefits.
Strength training becomes increasingly critical with age, not just cardio. "Using your muscles actually helps your mitochondria” — tiny structures inside cells that act like power plants — “turn over and do better."
Resistance training triggers different beneficial pathways than aerobic exercise does.
Exercise stimulates muscles to release beneficial chemicals into the blood that end up helping your brain. “Exercise is not just helpful for keeping your body generally healthy, but also can it help with your cognitive function.”
Caloric restriction works well in the lab, not so much in life
Caloric restriction (CR) — essentially limiting the number of calories you ingest day in and out — works by slowing cellular processes to allow repair time. When cells take in fewer calories, "they're working at lower speed...which gives the cell time to repair" damage that would otherwise accumulate.
In lab studies, cutting food by 30 percent begins to show longevity gains. But, as Murphy puts it, for humans, “I think it's a terrible way to live."
Intermittent fasting, which is different than CR because it limits not calories but rather the hours of the day to take in food, may not deliver benefits: A controlled study Murphy cites found people who simply tracked their eating did as well or better than intermittent fasters, who lost muscle as a result. (The benefit may simply come from paying attention to what you’re eating.)
Longevity drugs on the horizon
GLP-1 drugs like Ozempic may be "the longevity drug that nobody was looking for." Beyond weight loss, "if you could decrease people's addiction to smoking or alcohol or opioids, that would be a way to help people that is not directly related to aging, but it definitely could increase the average lifespan."
Metformin, an inexpensive diabetes drug, is being tested in the TAME trial for healthy aging2. Which could change prescribing practices because "a physician might be more comfortable prescribing something like metformin, even to people who don't have diabetes."
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Rapamycin and similar drugs may mimic caloric restriction without the suffering. These "rapalogs" (synthetic analogs of rapamycin) target cellular pathways that slow aging, though Murphy notes "we don't necessarily know how they work."
About eight biotech companies are now developing aging drugs through proper clinical trials, which are crucial. "We really need to be in a situation where we've tested things, we know they work, and we know that they're safe."
Sleep: the world’s best free longevity drug
Sleep deprivation causes measurable brain damage. "You need to rest in order for your brain to clean out toxins...you can actually see this in these scans that people do." Murphy calls sleep deprivation "super damaging."
Individual sleep needs vary, typically between 7 and 8 hours. While some people function long-term on less, Murphy notes they're "probably a mutant" with genetic variations.
Questions about napping and sleep quality remain unanswered. Expect results in a few years.
Cognitive health strategies
Mental sharpness is "probably the most important thing for us to maintain." This priority drives Murphy's research focus, because cognitive decline affects quality of life more than most physical changes.
Brain training games don't really work. "A lot of the brain-training things are actually specific for that function and not generally applicable." Crossword puzzles improve crossword skills — not general cognition.
Social engagement and continuous learning, on the other hand, provide real cognitive benefits. Though harder to study scientifically, Murphy notes: "Being interested in life and learning more things all the time... keeping socially active, there's actually good evidence that those are very beneficial."
Understanding biological vs. chronological age
Aging seems to occur in sudden jumps around ages 40 and 60, not gradually. Murphy wasn't surprised by the 40s shift because, as she put it, women have always had to confront menopause-related changes that have been "completely ignored by science for too many years."
Biological (DNA methylation) "clocks" marketed to consumers are of questionable accuracy.
Simple physical tests may predict longevity better than expensive biomarkers. The Short Physical Performance Battery (chair stands, balance, walking) predicts health outcomes.
Supplements and scams to avoid
Most supplements lack any evidence of efficacy. "There's no evidence one way or other what's in them or whether they work." Also: "What's in the bottle may not even be what's on the label."
The resveratrol/red wine story was largely hype. Despite initial excitement about the "French paradox" (French cuisine is high saturated fat but French rates of cardiovascular disease are well below other countries’), Murphy notes the French also "walk around a lot and they have socialized healthcare."
Wait for proper clinical trials before spending your money. Murphy distinguishes between companies "selling supplements and making a lot of money off it irresponsibly" and serious biotechs doing legitimate clinical trials.
Realistic longevity expectations
Maximum human lifespan (without intervention) hovers around 115-120 years. People who've reached these ages had no access to any longevity drugs, suggesting this is the baseline human maximum.
Contrary to what certain longevity chiselers say publicly, "There's not going to be one answer, one pill for everything."
Effective aging drugs will likely arrive "within the next decade."
Quality of life matters more than maximum lifespan. "Most people would agree that they don't want to live necessarily super long. What they really want to do is live a healthy life as long as they can."
Social realities and access
Economic inequality is the biggest barrier to longevity. Addressing poverty would "raise our average lifespan before we ever [develop] a drug."
"The reason that all of us have made it to adulthood is because of vaccines," and current threats to vaccination programs "will definitely shorten lifespan."
Future longevity treatments may worsen health inequities. “Some things are not going to be very equitably distributed."
What do you agree or disagree with? Leave a comment! If you found this helpful, please share this post with others.
“The Science of Longevity: A Conversation with Coleen T. Murphy,” University of Chicago Graham School, Aug. 28, 2025
“Coleen Murphy: The Science of Aging and Longevity,” Ground Truths (a Substack by Eric Topol, MD), Mar. 3, 2024
“How We Age: The science of longevity - Dr Coleen T Murphy,” York Ideas Festival (YouTube), June 21, 2024
“Q&A with Coleen Murphy,” Daily Princetonian, Oct. 21, 2024
https://www.afar.org/tame-trial
First some questions on resistance/strength training. The definition of what this means for a given person is vague. Questions such as Intense training vs very, very light training come up. Do you need at least a minimum number of exercises per sessions or could some exercises be spread out over the day? Is yoga that has stance work vinyasas/flow, balance work, planks.etc... in addition to other parts of yoga also considering strength training and is it enough to make a difference? What about pilattes mat workouts (no machines)? In general when we talk about exercise providing benefits we don't often qualify with how long, how hard, how often to know when the benefits are better. Doing something regularly is obviously better than doing nothing. Clearly people with physical limits can't do as much and part of the answer is that you need to do what you can based on where you are physically since extremes can lead to injuries. But on the flip side, super easy, super light movement that doesn't cause some exertion probably has less benefit.
Regarding calorie restriction: Many, many people who are older are also struggling with extra weight so they will do some form of calorie restriction in an attempt to manage it. It gets complicated when you try to trade off the benefits of excess weight vs doing calorie restriction. The intermittent fasting people that use light eating (600-800 or so calories on one or two days per week) are probably not depriving themselves all that much on average. Also I wonder if calorie content was mentioned since there are people in the various camps of paleo, always healthy (a limited and tailored lower carb approach that eventually allows for whole grain and treats in small amounts but doesn't restrict calories), mediterranean diets, etc... all try to help manage weight by the content of food rather than the quantity.
I guess I need to read the book.
The importance of exercise cannot be overstated. At 79, I finally got back into strength training almost 4 years ago. I'm confident this has allowed me to pull thru medical problems I've had recently far easier and more quickly than had I not been in decent physical condition. But I was sidelined for over a month and I can tell you that atrophy happens. Back in the gym!