01/09/2026
Grief is one of the most painful human experiences. We talk about the psychological toll, the sadness, the anger, the numbness. We talk about the emotional weight. But we rarely talk about what grief does to the physical body.
Mary-Frances O'Connor, a professor of psychology at the University of Arizona who directs the Grief, Loss and Social Stress (GLASS) Lab, has spent her career investigating exactly that . Her research focuses on the neurobiological, cardiovascular, and immune response to bereavement . In The Grieving Body, she answers questions that most people don't even know they should be asking: Can we die of a broken heart? What happens in our bodies when we're grieving? Why are we more prone to illness during times of enormous stress?
This is the follow-up to her acclaimed The Grieving Brain. And like its predecessor, it combines rigorous science with warmth and empathy. The book is illustrated with black-and-white charts and graphs, making the science accessible without dumbing it down.
There are plenty of books about grief. Most focus on the emotional journey, the stages, the coping strategies, the hope for healing. O'Connor doesn't ignore those things, but she takes a different approach. She asks: What is grief doing to your body?
This shift in perspective is crucial. When a person is grieving, they're not just sad. They're experiencing real, measurable physiological changes. Their cardiovascular system is under stress. Their endocrine system is dysregulated. Their immune system is compromised. The book explores the toll loss takes on each of these systems, and the implications for long-term well-being .
O'Connor's background makes her uniquely suited to this work. She holds a PhD in clinical psychology and completed a post-doctoral fellowship in psychoneuroimmunology, the study of how psychological processes affect the nervous and immune systems . She understands the mind and the body, and how they speak to each other.
Five Lessons from the Book
1. Yes, you really can die of a broken heart
This is not a metaphor. Broken heart syndrome, also called stress cardiomyopathy or Takotsubo cardiomyopathy, is a real medical condition. It's often brought on by stressful situations and extreme emotions . A sudden rise in stress hormones like adrenaline can stun the heart muscle, causing symptoms that mimic a heart attack: chest pain, shortness of breath, fainting . Most people recover quickly, but in rare cases, it can be fatal. O'Connor explains the science behind this phenomenon. Grief is not just an emotion. It's a biological event that can literally impact the heart.
2. Grief dysregulates the entire stress response system
The endocrine system, the glands and organs that make and release hormones, controls many important bodily functions, including growth, metabolism, and reproduction. Under normal conditions, it maintains a delicate balance. But grief throws that balance off. Chronic stress from grief keeps the body in a state of high alert. Stress hormones stay elevated. Sleep suffers. The body's systems work overtime, and over time, that takes a toll. The body isn't designed to sustain that level of stress indefinitely.
3. Your immune system takes a hit
Inflammation is a normal part of the body's response to injury or infection, a protective mechanism that triggers an immune response to fight off threats . But chronic inflammation is different. It's an abnormal immune response that doesn't end when it should. Over time, chronic inflammation can damage healthy cells, tissues, and organs, leading to diseases such as cancer, heart disease, diabetes, asthma, Alzheimer's, and autoimmune conditions .
O'Connor's research shows that grief creates conditions for chronic inflammation. The body is in a state of prolonged stress, and the immune system pays the price. This is why grieving people are more susceptible to illness, their defenses are down.
4. Coping behaviors matter, and not all coping is equal
Grief often leads to behaviors that make things worse: poor sleep, poor nutrition, isolation, substance use. These aren't failures of character. They're understandable responses to overwhelming pain. But they also compound the physical toll. O'Connor emphasizes the importance of body budget management, taking care of sleep, nutrition, and physical activity even when it feels impossible. Sleep is essential for body repair and brain maintenance . Nutrition reduces stress and inflammation . Physical activity is the body's natural antidote to stress. When grief makes these things feel pointless, that's exactly when they matter most.
5. Grief is an opportunity for healing, but not in the way you think
The subtitle is bold: "How the Stress of Loss Can Be an Opportunity for Healing." This could easily be read as toxic positivity, but O'Connor means something specific. The stress of grief reveals vulnerabilities in the body. It exposes what was already there, just below the surface. And that knowledge, painful as it is, can be a starting point. Understanding the physiological impact of grief is the first step toward mitigating it. It's not about rushing through grief or pretending it doesn't hurt. It's about recognizing that caring for the body is part of caring for the soul. The research-backed, warm, and empathetic approach O'Connor takes is aimed at helping readers not just survive grief, but understand it deeply enough to heal .
The Grieving Body is a book that answers questions you may not have known you were asking. Why does grief make you exhausted? Why do you get sick more often? Why does everything feel harder? O'Connor provides the science behind those experiences, and in doing so, she validates them.
The stress of loss is not just in your head. It's in your heart, your immune system, your hormones, your entire body. Understanding that doesn't make the pain go away. But it does help. It helps to know that what you're feeling is real, and that there are things you can do to protect yourself while you heal.
O'Connor writes with the authority of a researcher and the empathy of a clinician. She has spent her career studying the physiology of grief, and she brings that expertise to every page. The result is a book that is both informative and deeply reassuring. It says: This is happening to you. It's real. It's hard. And you are not alone.
BOOK: https://amzn.to/4oHPQ75
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