humanOS Radio

We tend to think of age in terms of the number of years we have been alive - meaning our chronological age. But the year that you were born is not necessarily an accurate measure of your health or your life expectancy. We are coming to realize that a better predictor is your biological age - and that can be quite different from your chronological age. So how do you learn your biological age? And what can you do with this information? In this episode of humanOS Radio, Dan speaks with Ken Raj. Ken is a Senior Scientific Group Leader at Public Health London, and has worked extensively with Dr. Steve Horvath of UCLA in developing and interpreting genomic biomarkers of aging. They are best known for developing the “epigenetic clock,” a tool that predicts life expectancy by examining age-related changes to DNA methylation, then using that information to calculate biological age in relation to chronological age. The epigenetic clock is able to predict life expectancy with remarkable accuracy, with a margin of error of plus or minus three years. In this podcast, we discuss: -How the epigenetic clock uses DNA methylation to compare biological to chronological age. -Whether DNA methylation changes are the “drivers” or the “passengers” of biological aging, and how direct a role they play in the aging process. -Whether or not epigenetic changes can be passed down from generation to generation. -Whether or not someone with a biological age greater than their chronological age is more likely to develop certain pathologies. -On the other hand, whether having a younger biological age than chronological age means greater health and a longer life. -What diet and lifestyle factors have been researched to show an impact on epigenetic aging. -Whether or not epigenetic drugs have the ability to modify this clock and slow aging. -The potential for extracting the exact mechanisms through which things like exercise and certain dietary interventions slow down epigenetic aging. -If the epigenetic clock can be used for earlier diagnosis of such age-related conditions as cancer, diabetes and neurodegenerative diseases, leading to better outcomes. To learn more, check out the blog!

In this episode of humanOS Radio, Dan speaks with John Newman. Dr. Newman is a geriatrician (a physician who specializes in the care of older people) at UCSF, as well as a professor at the Buck Institute for Research on Aging. He is chief investigator at the Newman Lab, where he is exploring ways to harness metabolic signals to promote health and resilience, particularly in older adults. Dr. Newman’s research focuses predominantly on ketone bodies - molecules produced in the liver when glucose is scarce, either due to restricted intake or prolonged physical activity. So we tend to think of them primarily as an alternative source of fuel, particularly in the context of a low carb diet. However, they are also intriguing with respect to aging, because of how they function as molecular signals, and how they influence gene expression.

Why do we age? The fundamental causes of aging at the molecular level are relatively well established. But the question of why aging happens in the first place is a more challenging one, one which has bedeviled evolutionary biologists and philosophers for years. You might think, intuitively, that the process of natural selection would gradually eliminate senescence. Aging increases mortality, and organisms that experience impaired function and ultimately die would not be able to produce as many offspring as one that was able to live (and to reproduce) indefinitely, or at least for a much longer timespan. So, you would assume that this would result in selection for organisms that live much longer, generate more offspring, and ultimately the causes of age-related deterioration would fade from the genome. Yet aging is very commonly observed. Why is that? Natural selection is strongest in early life. This makes sense - the natural environment is full of predators, disease, and other perils that often kill organisms when they are young and vulnerable. Consequently, genes and pathways that enhance survival and reproduction in early life are likely to be favored - even if they come at the cost of problems later in life, when selection is comparatively weak. But is aging inevitable? Can it be slowed, or postponed, or stopped altogether? In this installment of humanOS, Dan talks with Michael Rose. Dr. Rose is a Distinguished Professor of Ecology and Evolutionary Biology at UC Irvine. He is a prolific biologist whose research into the evolution of aging has effectively transformed that field. Rose’s laboratory has been testing the theory of antagonistic pleiotropy for nearly forty years, through artificial selection experiments in fruit flies. In what was perhaps his most famous experiment, Rose allowed flies to only reproduce successfully if they laid their eggs late in life. He discarded the eggs of any flies that laid eggs before they reached fifty years of age. Over a few generations, this population of flies evolved longer lifespans. Why might this be? Remember that natural selection is strongest early in life, and becomes weak later on. In theory, if adults reproduce when they are older, natural selection is apt to favor genes that enhance resilience (and reproduction) later into the lifespan. Dr. Rose's research into aging has also drawn him to some interesting (and possibly controversial) notions about evolutionary changes in the human diet, and how our age may influence how adapted we are to modern agricultural foods. To learn what that means, and its potential implications, check out the interview!

For the vast majority of human history, our species lived hunter-gatherer lifestyles. We can therefore learn much about how humans probably once lived by studying preindustrial societies. Research on preindustrial societies has consistently shown that these people have exemplary metabolic health. And when we consider that modern humans are succumbing to chronic diseases at an alarming rate, we clearly have much to learn from preindustrial people. In this episode of humanOS Radio, Greg Potter speaks with Professor Herman Pontzer about what Herman has learned from his research on hunter-gatherers. Herman's findings led him to develop the counterintuitive hypothesis that how physically active we are each day may scarcely affect how many calories we burn… … no, I’m not kidding. As he explains in the podcast, however, this hypothesis in no way discounts the importance of being physically active – far from it! Tune in for more on Herman’s fascinating research on physical activity, diet, and more.

Do smartphones really affect the timing and quality of your sleep? In this episode of humanOS Radio, Dan speaks with Professor Jeanne Duffy from Harvard Medical School on her most recent research investigating this question.

Stress is something we all experience all too frequently. The effects of different stressors accumulate, and when the resultant load is excessive, we are at increased risk of a range of diseases. So, to avoid the amount of stress we experience exceeding our bodies’ capacities to cope, it would be useful to have a way to monitor how we’re responding to stressors. In the last few years, numerous wearable devices that claim to monitor how we’re responding to stress have become available, and most of these measure either heart rate variability (HRV) or pulse rate variability. In this episode of humanOS Radio, Professor Phyllis Stein explains what you need to know about HRV, including what it is, why people measure it, and whether you should measure your own HRV.

Nutrition is perhaps the most emotionally charged of all of the applied sciences. It’s not hard to see why. For one thing, all of us eat, meaning that every single one of us is personally invested in this topic, and we interact with it all the time. We all develop a sense of expertise, in a way that we might not for something a bit more removed from our daily life, like robotics or civil engineering. In addition, food is arguably the most powerful and primal motivator for animals, ourselves included. And every single one of us has cultivated deep-seated dietary preferences, often established in our formative years. In other words, we are all biased, to varying degrees. It's hard for us to view our favorite foods in an entirely objective way - even when they are slowly making us sick. To further complicate matters, nutrition is very difficult to research rigorously, and studies are often rife with confounders and apparently contradictory results. The controversial nature of nutrition science was on full display this Tuesday, when Stephan Guyenet and Gary Taubes appeared together on the Joe Rogan Experience podcast to debate the causes of obesity and type 2 diabetes. Gary and Stephan have very different points of view on this subject, informed by rather different approaches to scientific literature. But as is often the case in debates, there was much that Stephan wanted to say but didn’t get an opportunity to address. That’s why we have welcomed him back to humanOS Radio, to reflect upon his experience on Joe Rogan’s podcast and to further elucidate the causes of obesity and insulin resistance. Click below to check out the interview!

In this podcast, Greg Potter speaks with James Hewitt, who has a particular interest in how people can achieve sustainable high performance. In addition to his role as Chief Innovation Officer at Hintsa Performance, James is doing a PhD at Loughborough University, where his research focuses on how workers’ lifestyle and work patterns influence their wellbeing and performance. In this interview James shares many useful insights regarding how to perform better at work. This podcast also includes a discussion on: - What “knowledge work” is -What traits and behaviors differentiate the successful from those who fall by the wayside -The importance of understanding our daily rhythms in cognitive function -How planning sports training has influenced the way James helps people perform better at work -The idea of “cognitive gears”, and why many of us would benefit from clearer demarcations between focused work and recovery -The reciprocal relationship between physical endurance and mental endurance -Physical activity for workers -The importance of mood and learning in workplace performance -How to start the day on the right foot -How to prepare for restorative sleep at night (note that I've written about caffeine, alcohol, light exposure, and temperature previously) -How to become better at public speaking

Brain injury is more pervasive and problematic than many people think. Every day, about 150 people die from traumatic brain injury-related deaths in the US alone, and whether you participate in a contact sport, work in the military, or simply travel on roads, you may at some point suffer the kind of event that incites brain injury. The problem is that brain injury is associated with numerous negative health consequences, including mental health issues and diseases such as Parkinson’s. Fortunately, there are things that we can do to help us protect against the negative consequences of brain injury. There are good reasons to think that we may benefit from using exogenous ketones for brain injury, for example. This episode of humanOS Radio explores these subjects with Dr. Tommy Wood.

Whether you want to look great at the beach, perform better at sports, or ward off disease, it’s important to optimize your protein intake. This brings us to the latest episode of humanOS Radio, in which Dan speaks with Professor Stu Phillips from McMaster University. Tune in to find out more!

Aging is arguably the leading risk factor for chronic diseases in the modern world. We have historically thought of aging as an inexorable decline of function, driven by the passage of time - something that we simply have to accept, and that cannot be changed. But what if aging were actually a modifiable risk factor? Your chronological age, meaning the length of time that you have been alive, obviously cannot be changed. But we know that biological aging can vary significantly, even among individuals who are of similar chronological age. If we can better understand the fundamental mechanisms that underlie biological aging, we might be able to devise interventions that could prevent or delay age-related diseases. One of the relevant processes is cellular senescence. Cellular senescence is a phenomenon through which normal cells irreversibly cease to divide in response to genomic damage. Senescent cells accumulate in the body as we get older, and they actually do a lot of bad stuff in the body. Senescent cells secrete pro-inflammatory factors, like cytokines, which induces a state of chronic low-grade inflammation. But it gets even worse. These senescent cells can also drive other healthy neighboring cells into senescence. So senescent cells are basically microscopic zombies! This has driven interest in identifying senolytics - compounds that can selectively kill senescent cells (while leaving normal cells alone). In this episode of humanOS Radio, Dan talks to Paul Robbins. Paul is the principal investigator at the Robbins Lab at Scripps Research Institute. Notably, his lab has been screening for drugs that can safely and effectively clear out senescent cells. This research has produced some remarkable results in animal models. For example, he and colleagues found that older mice that were given senolytics became faster and stronger, and experienced a 36% increased median post-treatment lifespan, compared to a control group. Wow! That’s just a tiny snapshot of this incredibly important work. To learn more, please check out the interview!

Why is it so hard for us to make healthy lifestyle changes - even when we have the knowledge to do better? Most of us have a list of things we would like to change. Maybe you’d like to lose thirty pounds, or be able to do fifty pushups, or run a marathon. But each of these comes with a long list of associated behaviors - many of which aren’t intrinsically rewarding - that are required to achieve and maintain these goals. It’s no wonder the statistics on weight loss are so underwhelming. On this episode of humanOS Radio, Dan speaks with James Clear. James is an author and entrepreneur who is focused on habits, decision-making, and continuous improvement. His work has appeared in the New York Times, Time magazine, and other major media outlets. In his latest book, “Atomic Habits,” James draws upon a wide array of evidence from psychology, biology, and cognitive neuroscience to construct a guide for building and reinforcing good habits and abolishing bad habits. So what are habits? James defines habits as behaviors that are repeated enough times to be nearly automatic. This means they are not demanding cognitive effort or willpower. Like brushing your teeth, or heading to the gym at 5:00pm every day, or eating a smoothie every day for breakfast. These automatic processes, which are mostly mundane things that we take for granted, are actually foundational to all of our goals. The problem, of course, is that we generally don’t see the immediate payoff for any of these behaviors. You don’t drop twenty pounds just switching from regular to diet soda one time. It is only after you’ve committed to these behaviors for a while - after your efforts have compounded - that we start to see the difference. That is why we need to develop a system to assess our current habits and build better ones. This is where “Atomic Habits” comes into play.

Why do we need to sleep? Part of what makes sleep so fascinating, as a field of research, is that it is such an enigma. Sleep is a profoundly vulnerable state, leaving us at the mercy of predators and the environment, and unable to defend ourselves or our possessions. It's also largely unproductive. Yet we spend about a third of our life in slumber. Moreover, sleep also seems to be nearly universal in the animal kingdom. Indeed, we have yet to identify an animal that clearly does not sleep at all, or even one that can forego sleep without experiencing physiological consequences. All of this, taken together, unambiguously shows that sleep is extremely important. And this makes it all the more remarkable that the actual purpose of sleep remains elusive. One idea is that sleep may function as an antioxidant for the brain, protecting neural tissue from the ravages of oxidative stress. This hypothesis largely fell out of favor, but researchers have recently started to revisit this compelling notion. In this episode of humanOS Radio, Dan talks to Mimi Shirasu-Hiza. Mimi is an associate professor of Genetics and Development at Columbia University. Her lab uses circadian mutants of fruit flies to unveil the molecular mechanisms that underlie circadian-regulated physiology. Mimi and her colleagues hypothesized that fruit flies with various genetic mutations that reduce their sleep might share a common physiological defect due to that sleep loss, but independent of the specific mechanisms driving their reduced sleep. And if they could find such a defect, that might reveal the core function of sleep in animals (including us). Through an elegant series of experiments, Mimi and her team did indeed uncover a shared defect, which points to a possible purpose of sleep in fruit flies and perhaps in humans. Check out the interview to find out what they discovered and what it might mean for us!

All of us know that lack of sleep impairs cognitive performance. But we are now realizing that sleep quality, and how long that you spend in deeper restorative sleep, also plays an important role in brain function. Today on humanOS Radio, Dan talks to Kristine Wilckens. Kristine is an assistant professor in the Sleep and Chronobiology Center in the Department of Psychiatry at the University of Pittsburgh. Her research has focused on how sleep structure can be altered to enhance cognitive function. In this interview, we review the role of slow wave sleep in learning and memory consolidation, and the kinds of activities that have been demonstrated to promote slow wave sleep. Many of these techniques - like heat exposure - are things that you can experiment with yourself right now. Check out the interview to learn more!

The subject of alcohol and health is complex. There is evidence that alcohol can be health-promoting, but more recent evidence has suggested it isn't healthy for humans in any amount. The ancient Greeks only drank their wine diluted. They believed that only barbarians would drink unmixed or undiluted wine as it would bring out a type of behavior that would cause mayhem. In this episode, Dan speaks with Todd White, CEO of Dry Farm Wines, to discuss and compare the differences between conventional wines with natural wines - which tend to be lower in alcohol, calories, sugar, and additives, while higher in phytochemicals like polyphenols - as well as a discussion of the effects these different types of wine on health. Be sure to check blog.humanOS.me for a longer discussion of alcohol and health.