The XX Lab

Sarah

4.9 (13)
Self-Improvement

Welcome to The XX Lab, where I talk with scientists and top-performing women to give you insights that you can use in everyday life. This is not another health podcast telling women to optimize endlessly or chase extreme longevity. It’s a science+life podcast for women who want to feel better now—not just live longer later.

5h ago

WHOOP Scientist: The #1 Habit for Better Sleep, Recovery & Long-Term Health | Dr. Kristen Holmes #17

Your WHOOP recovery score dips, you slept fine, you did everything right, so why does the number look worse? What if that "bad" reading is your body working exactly as it should? In this episode of The XX Lab, Dr. Sarah Hill sits down with Dr. Kristen Holmes, Global Head of Human Performance and Principal Scientist at WHOOP, to explore what wearables really measure in women, resilience to hormonal change, sleep-wake regularity, mental health as the foundation of performance, and her new book, Aligned. Whether you are curious about what your wearable is telling you, navigating perimenopause, or rethinking how mental health, sleep, and recovery connect, this conversation offers a women-first lens on performance and resilience. KEY TAKEAWAYS: - A lower recovery score during your cycle is often normal biology, not a sign you did something wrong. - Women on hormonal birth control show fewer perturbations, and their data can resemble a man's. - Cardiovascular amplitude is a novel, patented marker of resilience that HRV and resting heart rate miss. - The resilience you build in your 20s and 30s shapes your perimenopause and menopause experience. - If your mental health is not right, top fitness and performance stop mattering very quickly. - Sleep-wake regularity predicts disease better than sleep duration and supports mental health too. Timestamps The Scientist Behind Your WHOOP Recovery Score (00:00) From Elite Coaching to Human Performance Science (02:25) Availability: The Metric That Predicts 86% of Success (04:45) Leaving Princeton to Scale Recovery at WHOOP (10:15) Why Your Cycle Changes Your Recovery Score (14:55) Resilience to Hormonal Change and Amplitude (18:10) Why Building Resilience Starts in Your 20s and 30s (24:15) The New Book Aligned and Losing Her Mother (32:45) Why Mental Health Is the Foundation of Performance (44:00) Sex Differences in Sleep and the Light Diet (55:25) The HEAL Framework and Sleep-Wake Regularity (1:11:55) Guest Bio Dr. Kristen Holmes is the Global Head of Human Performance and Principal Scientist at WHOOP, where she has led research on recovery, sleep, and women's health since 2016. A two-sport All-American at Iowa and seven-year US National Field Hockey Team member, she was one of the most successful coaches in Ivy League history at Princeton, winning 12 league titles in 13 seasons. A psychophysiologist, her work focuses on how psychology, physiology, sleep, and recovery shape human performance. She is the author of Aligned. - Aligned (book): https://a.co/d/aligned - Instagram: https://www.instagram.com/kristen_holmes2126 - WHOOP: https://www.whoop.com *** 📘 Go deeper with Dr. Sarah Hill's books, both science-backed guides to understanding your own biology: The Period Brain: the new science of why we PMS and PMDD, and how to feel your best all month long 👉 https://www.amazon.com/Period-Brain-Science-Manifesto-Women/dp/0063382474 This Is Your Brain on Birth Control: how the pill shapes mood, attraction, and behavior in ways most women are never told 👉 https://www.amazon.com/This-Your-Brain-Birth-Control/dp/0525536035
Aug 31

Shira Boehler: The Cancer That Kills More Young Women Than Breast, Ovarian & Colon Combined | #16

You did everything right, kale, running, annual blood tests, and still ended up with a mass in your lung. So why does the disease killing more young, healthy women than breast, ovarian, and colon cancer combined still carry the stigma of a smoker's disease? In this episode of The XX Lab, Dr. Sarah Hill sits down with Shira Boehler, lung cancer survivor, author of the New York Times bestseller One Scan Saved My Life, and founder of the Cancer Doesn't Care foundation, to explore why lung cancer is rising in young non-smoking women, sex differences in medicine, the toll on caregivers, and why a $200 scan could rewrite the guidelines. KEY TAKEAWAYS: - Lung cancer kills more young, healthy women than breast, ovarian, and colon cancer combined, yet gets a fraction of the awareness and funding. - "If you smoke, you get lung cancer" has curdled into "if you have lung cancer, you smoked", a stigma that keeps survivors silent. - The real truth is simpler and scarier: if you have lungs, you can get lung cancer. - Non-smoking women in parts of Asia get lung cancer at higher rates than smoking men, pointing to a female health crisis science hasn't explained. - Studying diseases separately in men and women may accelerate progress and reveal sex-specific risk factors. Timestamps 00:00 One Scan Saved My Life: Shira Boehler's Story 05:37 Pushing for the Low-Dose CT Doctors Dismissed 08:52 Why Lung Cancer Kills More Young Women Than Breast Cancer 14:08 The Myth That Only Smokers Get Lung Cancer 21:31 How Women's Heart Attack Symptoms Went Ignored for Decades 27:20 How She Told Her Kids She Had Cancer 39:32 Why Your Surgeon Should Warn You About Depression 43:52 The Ripple Effect: Susan Wojcicki and Hidden Costs 53:00 What to Say When Your Doctor Refuses the Scan 56:14 How to Get a Low-Dose CT for Under $500 1:04:36 If She Could Rewrite the Screening Guidelines 1:10:07 The One Thing She Wants Every Woman to Do Guest Bio Shira Boehler is a lung cancer survivor and author of One Scan Saved My Life, a New York Times bestseller chronicling her diagnosis as a healthy, non-smoking runner and mother of four. Diagnosed at 43 after a mass was caught incidentally, she had half her right lung removed and was declared cancer-free at stage one. She founded the Cancer Doesn't Care foundation, which funds low-dose CT screenings for those who cannot afford them, and focuses on early detection, dismantling stigma, and modernizing screening guidelines. - Book: One Scan Saved My Life https://a.co/d/006gnafi - Foundation: https://www.cancerdoesntcare.com - Instagram: https://www.instagram.com/shiraboehler/ *** Go deeper with Dr. Sarah Hill's books, both science-backed guides to understanding your own biology: The Period Brain: the new science of why we PMS and PMDD, and how to feel your best all month long https://www.amazon.com/Period-Brain-Science-Manifesto-Women/dp/0063382474 This Is Your Brain on Birth Control: how the pill shapes mood, attraction, and behavior in ways most women are never told https://www.amazon.com/This-Your-Brain-Birth-Control/dp/0525536035
Aug 24

Why Does Attraction Change in Relationships? with Dr. Andrea Meltzer | #15

Why does attraction change once you're in a long-term relationship? And could hormones, physical attractiveness, and even what happens after sex shape how satisfied couples remain over time? On this episode of The XX Lab, Dr. Sarah Hill sits down with Dr. Andrea Meltzer, Professor of Social Psychology at Florida State University, to explore the science of attraction, mate choice, sexual satisfaction, and long-term relationship health. Dr. Meltzer has spent years studying how individual differences and interpersonal dynamics shape romantic relationships. Her research uses longitudinal and experimental methods to examine newlywed couples, giving researchers a rare look at how attraction, stress, sexual satisfaction, and perceptions of partners influence relationship outcomes over time. Does physical attractiveness predict relationship satisfaction?The conversation begins with a surprising finding about physical attractiveness and relationship satisfaction. Dr. Meltzer explains why attractiveness can matter differently for men and women once a relationship becomes established, and why the person you find attractive from across the room isn't necessarily the same person you experience as attractive when they're your partner. Sarah and Andrea also discuss how people tend to see their romantic partners more positively than outside observers do. Relationship satisfaction and commitment can shape how attractive we perceive our partners to be, suggesting that attraction isn't simply a fixed reaction to someone's physical appearance. How can couples protect relationship satisfaction over time?Relationship satisfaction tends to decline on average over the course of marriage, but Dr. Meltzer emphasizes that couples differ considerably in how steep that decline is. Her research points toward factors that may help buffer against those changes. The conversation ends with practical ideas for maintaining strong relationships, including positive communication, supporting a partner's goals, and creating novel experiences together. Dr. Meltzer also highlights something couples may underestimate: the role that outside stress can play inside the relationship. This episode is for anyone curious about the science of attraction, hormones, sex, mate choice, marriage, and what actually helps romantic relationships stay satisfying over time. KEY TAKEAWAYSRelationship attraction is shaped by context, meaning a partner's personality, behavior, status, and relationship dynamics can matter alongside physical appearance.Sexual afterglow can last roughly 24 to 48 hours after sex, potentially helping couples maintain a sense of connection between sexual experiences.Stronger sexual afterglow has been associated with greater relationship satisfaction months later, suggesting that the effects of sex may extend beyond the sexual encounter itself.Sexual frequency appears to matter up to a point, while sexual afterglow may become particularly relevant once couples are already meeting their desired level of sexual frequency.Positive communication and novel experiences together may help protect relationship satisfaction, while outside stress is an often-underestimated influence on romantic relationships.GUEST BIODr. Andrea Meltzer is a Professor of Social Psychology at Florida State University whose research examines relationship development, maintenance, and well-being. Her work focuses on how individual differences, stress, sexual satisfaction, partner perceptions, and interpersonal dynamics shape romantic relationship outcomes over time. Follow The XX Lab for more science-based conversations about women's health, psychology, relationships, and human behavior.
Aug 17

7 Surprising Things Your Voice Reveals About You with Dr. Greg Bryant | #14

What does your voice say before you even finish a sentence? Long before someone processes your words, their brain has already begun decoding your voice. In a fraction of a second, people can make surprisingly accurate judgments about your age, biological sex, emotional state, health, native language, and even aspects of your social relationships. The fascinating part? Most of this happens automatically. In this episode of The XX Lab, Dr. Sarah Hill sits down with cognitive scientist Dr. Greg Bryant, Professor and Chair of Communication at UCLA, to explore the hidden science of human vocal communication. Drawing from evolutionary psychology, cognitive science, and behavioral biology, Dr. Bryant explains why our voices evolved to carry so much information and how humans have become remarkably skilled at interpreting those signals. Sarah and Greg discuss how listeners detect subtle vocal cues associated with illness, strength, stress, confidence, and authenticity. They also explore why these abilities likely evolved to help humans navigate cooperation, competition, caregiving, and mate selection. Whether you're interested in psychology, neuroscience, communication, women's health, or human behavior, this conversation offers a fascinating look at one of the most overlooked aspects of everyday life: the science hiding inside every conversation. KEY TAKEAWAYSYour voice communicates far more than the words you speak, including biological and social information.Listeners can often estimate a person's age, biological sex, emotional state, and native language after hearing only a brief vocal sample.Subtle vocal characteristics can provide clues about illness, physical condition, and overall health.Humans evolved specialized abilities to rapidly interpret vocal signals because they support cooperation, survival, and social decision-making.Genuine laughter carries different acoustic characteristics than polite or socially motivated laughter.Vocal communication combines language, context, and sound into a remarkably rich social signal.Evolutionary psychology helps explain why humans are exceptionally tuned to vocal cues.Understanding how voices shape perception can improve communication, relationships, and social awareness. GUEST BIODr. Greg Bryant is a cognitive scientist who studies communication and cognition from an evolutionary perspective. He serves as Professor and Chair of the UCLA Department of Communication, where his research examines vocal communication, laughter, music perception, social cognition, cultural evolution, and behavioral biology. His work combines laboratory experiments, cross-cultural field research, acoustic analysis, and comparative studies across species. GUEST LINKSSpotify (Music) https://open.spotify.com/artist/7txtvHi6cCtJJRhZX2zBlJ HOST LINKSWebsite https://www.sarahehill.com Instagram https://www.instagram.com/sarahehillphd LinkedIn https://www.linkedin.com/in/sarahehillphd If you enjoyed this conversation, follow The XX Lab, leave a review, and share this episode with someone who's fascinated by the science of human behavior.
Aug 10

Why Women Compete Differently Than Men with Dr. Khandis Blake | #13

Are women really less competitive than men, or have we been measuring competition the wrong way? In this episode of The XX Lab, Dr. Sarah Hill sits down with Dr. Khandis Blake, PhD, evolutionary psychologist and researcher, to explore how hormones, competition, confidence, mate preferences, and modern environments shape women's behavior in ways that are often misunderstood. Why do women compete differently than men?Drawing on years of research in evolutionary psychology, Dr. Blake explains why women often compete through different strategies than men, how status and relationships influence those behaviors, and why common stereotypes fail to capture the full picture. Sarah and Khandis discuss the evolutionary pressures that shaped female competition and why cooperation has been just as important to women's success as competition itself. The conversation also explores how hormonal fluctuations across the menstrual cycle can influence confidence, ambition, social behavior, and partner preferences. Together, they unpack what researchers know, what remains uncertain, and why nuance matters when discussing sex differences. How do hormones shape everyday decisions?Sarah and Khandis examine research on hormonal contraception, workplace behavior, mate choice, and the gender pay gap, asking whether biology and modern culture interact in ways that help explain differences in outcomes without reducing them to simple cause-and-effect stories. Whether you're interested in women's health, psychology, relationships, or understanding the science behind human behavior, this episode offers an evidence-based conversation that challenges common assumptions while respecting the complexity of the research. Key TakeawaysWomen often compete through social and relationship-based strategies rather than direct physical competition.Cooperation and competition have evolved together as complementary survival strategies.Hormonal changes can subtly influence confidence, motivation, and social behavior.Confidence is influenced by both biology and environment rather than either factor alone.Hormonal contraception may affect some aspects of psychology differently across individuals.Mate preferences are flexible and can shift depending on context and life stage.Evolutionary psychology helps explain behavioral patterns without determining individual outcomes.Biological differences should inform research without reinforcing stereotypes.Understanding women's psychology requires considering both culture and biology.Scientific nuance is essential when discussing hormones, behavior, and sex differences. Guest BioKhandis Blake is an evolutionary psychologist whose research examines female competition, hormones, mating psychology, status, and human behavior. Her work explores how evolutionary science can help explain modern social dynamics while challenging common misconceptions about women. Enjoyed this conversation? Follow The XX Lab and leave a review to help more people discover evidence-based conversations about women's health, psychology, and human behavior.
Aug 3

The Wellness Industry Isn't Making Us Healthier with Sarah Ann Macklin | #12

We have more health information than ever before, yet we're getting sicker, more stressed, and more overwhelmed. So what's missing? In this episode of The XX Lab, Dr. Sarah Hill welcomes Sarah Ann Macklin, registered nutritionist, former international model, host of Live Well Be Well, and author of Healthy Shouldn't Be This Hard. Together, they explore why today's $8.5 trillion wellness industry isn't delivering better health and why the missing ingredient may have less to do with information and more to do with how we relate to ourselves. Why isn't more health advice making us healthier?Sarah Ann shares her remarkable journey from the fashion industry to clinical nutrition, revealing how years of chasing perfection ultimately reshaped her understanding of health. She explains why fear-based wellness messaging often backfires, how self-worth influences health behaviors, and why sustainable habits begin with self-compassion rather than self-criticism. The conversation also explores mindset, stress, body awareness, food insecurity, nutrition science, and the fascinating ways our thoughts can influence our physiology. Sarah and Sarah discuss why understanding your body's signals is essential for making lasting lifestyle changes and why health doesn't have to be built on restriction or guilt. What does it really mean to work with your body?From the science of interoception to practical advice about whole foods, supplements, cooking, and behavior change, this episode offers an evidence-based roadmap for building a healthier relationship with food and with yourself. Rather than chasing perfection, Sarah Ann explains why learning to trust your body may be one of the most powerful health interventions available. Whether you're overwhelmed by conflicting nutrition advice, struggling to build healthier habits, or simply looking for a more compassionate approach to wellness, this conversation offers practical tools backed by science. Key TakeawaysMore health information doesn't automatically lead to better health outcomes.Self-compassion is a critical foundation for long-term behavior change.Fear-based wellness marketing often undermines healthy habits.Whole foods support healthier body signals than highly processed foods.Mindset can influence physiological responses to nutrition and exercise.Chronic stress affects both physical and mental well-being.Supplements should support, not replace, a nutrient-rich diet and should be guided by appropriate testing when possible.Sustainable health comes from working with your body instead of constantly trying to fix it. Guest BioSarah Ann Macklin is a registered nutritionist, former international model, founder of the Be Well Collective, host of the Live Well Be Well podcast, and author of Healthy Shouldn't Be This Hard. Her work focuses on evidence-based nutrition, behavior change, and helping people build healthier relationships with food and themselves. Guest LinksWebsite: https://www.sarahannmacklin.comLive Well Be Well PodcastInstagram: @sarahannmacklinBook: Healthy Shouldn't Be This HardBe Well Collective If you enjoyed this conversation, follow The XX Lab and leave a review to help more listeners discover science-backed conversations about health, psychology, and human behavior.
Jul 26

Why Are We So Lonely Despite Being So Connected? with Dr. Bill von Hippel | #11

We're more connected than any generation in history, yet loneliness continues to rise. What happened? In this episode of The XX Lab, Dr. Sarah Hill sits down with Dr. Bill von Hippel, evolutionary psychologist and bestselling author of The Social Paradox, to explore why the very freedoms that define modern life may also be driving us further apart. Why does modern life leave so many people feeling isolated?Drawing from evolutionary psychology, Bill explains how humans evolved to depend on tight-knit communities for survival and why today's culture of independence, mobility, and individual achievement often clashes with those ancient social instincts. Together, he and Sarah unpack the surprising ways technology, urbanization, modern dating, and changing family structures have reshaped our relationships and our well-being. The conversation explores why autonomy and connection often pull us in opposite directions, how our brains respond to social isolation, and why loneliness isn't simply an emotional experience but a biological signal that evolved to keep us connected to others. Can we build happier lives by understanding our evolutionary past?Bill shares practical insights from The Social Paradox, discussing why meaningful relationships remain one of the strongest predictors of happiness, health, and longevity. He also explains how modern environments amplify stress, why friendship becomes harder in adulthood, and what individuals can do to cultivate stronger social networks despite the demands of contemporary life. Whether you're interested in psychology, relationships, health, or understanding why modern life often feels disconnected, this episode offers a thoughtful, science-backed perspective on one of the defining challenges of our time. Key TakeawaysHuman brains evolved for close-knit communities rather than large, anonymous societies.Loneliness functions as a biological signal that encourages social reconnection.Modern independence often comes with hidden psychological costs.Strong relationships consistently predict better physical and mental health.Evolutionary mismatch helps explain why modern environments can increase stress and isolation.Technology connects us efficiently but doesn't always satisfy our need for meaningful social bonds.Adult friendships require intentional effort because modern lifestyles reduce repeated social contact.Balancing autonomy with connection leads to greater long-term well-being.Understanding our evolutionary history provides valuable context for today's mental health challenges.Small, consistent investments in relationships can have an outsized impact on happiness. Guest BioDr. Bill von Hippel is an evolutionary psychologist, professor, and bestselling author of The Social Paradox. His research explores human behavior, social relationships, happiness, evolutionary psychology, and the ways modern environments shape our minds and well-being. Guest LinksWebsite: https://billvonhippel.comBook: The Social ParadoxResearch publicationsUniversity profile (if included in your transcript resources) If you enjoyed this conversation, follow The XX Lab and leave a review to help more listeners discover evidence-based conversations about women's health, psychology, and human behavior.
Jul 19

Why Dating Apps Make Commitment Harder | #10 Dr. Cari Goetz

Dating apps promised more choice. But what if more choice is making relationships harder to build? In this episode of The XX Lab, Dr. Sarah Hill sits down with Dr. Cari Goetz, evolutionary psychologist and relationship researcher, to explore the psychology of mate switching, online dating, sexual exploitability, casual sex, and the hidden forces shaping modern relationships. Cari explains how humans evolved in environments with relatively small pools of potential partners, and why today's endless swiping culture may be activating psychological mechanisms that were never designed for thousands of options. The conversation dives into the paradox of choice, why people often become less satisfied when they have more alternatives available, and how dating apps may subtly encourage a constant comparison mindset. How does online dating affect long-term relationships?Sarah and Cari unpack research suggesting that the way people select partners online may differ dramatically from how humans historically chose mates. Instead of evaluating a few potential partners holistically, many daters begin filtering candidates by isolated traits, which can make commitment more difficult and increase the temptation to keep searching for someone better. The discussion also explores practical strategies for using dating apps without falling into a perpetual mate-switching mentality. If you've ever wondered why dating can feel so exhausting, why casual sex can be emotionally complicated, or why modern relationship advice often feels disconnected from human psychology, this episode offers a nuanced, research-based perspective. Key TakeawaysThe paradox of choice can make people less satisfied with a dating partner when they perceive endless alternatives.Limiting the number of dating profiles you evaluate may improve decision-making and reduce comparison fatigue.Early-stage dating is often when people are most vulnerable to a constant "someone better might be out there" mindset.Being intoxicated, fatigued, or appearing less aware can increase perceptions of vulnerability.Men who are low in agreeableness and highly interested in casual sex were more likely to perceive women as sexually exploitable.Sexual regret and sexual disappointment are distinct emotions and may be conflated in some research.Women's casual sex experiences are often shaped by potential costs such as pregnancy, STIs, and reputational concerns.Women's sexual motivation may increase during the years when fertility is beginning to decline, potentially reflecting an evolved reproduction-expediting mechanism.Guest BioDr. Cari Goetz is an evolutionary psychologist whose research focuses on mating psychology, mate switching, sexual exploitation, relationship dynamics, and reproductive behavior. She is a faculty member at California State University, San Bernardino and has published extensively on human mating strategies and social behavior. Guest LinksCSUSB Profile: https://www.csusb.edu/profile/cgoetzLinkedIn: https://www.linkedin.com/in/cari-goetz-62725542/Google Scholar: https://scholar.google.com/citations?user=BIKau3cAAAAJ&hl If you enjoyed this conversation, follow The XX Lab and leave a review to help more listeners discover evidence-based discussions about women's health and human behavior.

Trailer

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June 1st

4.9

out of 5

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Welcome to The XX Lab, where I talk with scientists and top-performing women to give you insights that you can use in everyday life. This is not another health podcast telling women to optimize endlessly or chase extreme longevity. It’s a science+life podcast for women who want to feel better now—not just live longer later.

Creator

Sarah
Years Active

2026
Episodes

18
Rating

Explicit
Copyright

© 2026 Sarah