Are you in control of your nervous system – or is it in control of you? It’s a question that deserves your attention, because the answer affects everything from how well you sleep to how you react when life is hard. And my guest this week believes most of us have more agency than we realise.

Dr Kristen Holmes is Global Head of Human Performance and Principal Scientist at the wearable-tech company WHOOP. She’s also a former US national field hockey player and one of the most successful coaches in Ivy League history. In her new book, Aligned, she argues that a well-regulated nervous system is the foundation for our health, performance and relationships.

We start by exploring what a balanced nervous system looks like in daily life, why some people need to begin with their body and others with their mind, and why Kristen prefers the word agency to control.

Kristen then talks me through a study she led with WHOOP, in which 39,000 of its members tried four simple, free daily behaviours, and what happened to their sleep and heart health as a result. She explains why most of us have no idea when our body naturally wants to fall asleep, why sleep consistency predicts health more strongly than sleep quantity or quality – and the single metric she believes reveals most about someone’s health.

We also cover why variety matters in how we move, why eating earlier suits our metabolism, and why so many of us fall ill as soon as we go on holiday. And Kristen shares a powerful 72-hour exercise for auditing your daily actions against your values.

In the second half, the conversation becomes deeply personal. Kristen talks about growing up around alcoholism, the trauma she experienced as a child, and how she found her way to forgiveness through curiosity. We discuss emotions rooted in trust versus fear, the role of nostalgia, and how joy differs from happiness. She also shares the meditation practice that helped her learn to love herself, and the science showing how it benefits the body.

This is a conversation for anyone who wants practical, evidence-based steps to better sleep, energy and resilience. But, perhaps more importantly, it’s for anyone who senses that lasting change also requires some inner work. Kristen brings both the data and the lived experience – and I think everyone will find something here to carry into their own life.