When I lost Nahla, my German Shepherd, I expected to be heartbroken. What I didn't expect was what happened to my body.
Foods I'd eaten for years suddenly made me unwell. I couldn't sleep. I was exhausted in a way that felt bone-deep. My nervous system felt like it was running on high alert, all day, every day. I didn't recognise myself.
For a long time I searched for answers — supplements, tests, medical appointments. What I didn't fully understand then was that my body wasn't malfunctioning. It was grieving.
If you've experienced something similar after losing a dog, I want you to know: this is real, it is documented, and it makes complete sense.
Grief isn't just emotional. It's biological.
When we lose someone we love — including a pet — the body can go into fight-or-flight mode. Reminders of the one we lost can trigger a stress response, causing cortisol levels to rise. This isn't a metaphor. It is a measurable physiological event. Nebraska Medicine
Your beloved companion provided emotional regulation, routine, and comfort that your body had adapted to over years or even decades. When that presence suddenly disappears, your nervous system goes into overdrive trying to locate that missing piece of your daily life. Love, Baxter
For those of us who have lived with dogs, this is especially significant. Nahla regulated me. Her presence grounded me. The morning routine, the walks, the weight of her beside me — my nervous system had built itself around her. When she was gone, my body noticed in ways I couldn't have anticipated.
What the science says
Grief activates similar brain pathways as physical pain and social rejection. The body experiences loss as a real rupture in connection — which is why memories, routines, or quiet moments can trigger intense physical reactions long after a pet has passed. The Cosmic Craft
Here is what research shows can happen in the body after a significant loss:
Cortisol dysregulation
Cortisol levels can remain elevated for at least the first six months of bereavement, affecting heart and immune functioning, as well as quality of sleep and life. When the loss is new, the nervous system may keep acting like the emergency is still happening — waking at 3am, racing thoughts, a pounding heart, a churning stomach, or a sudden wave of exhaustion after doing something small. Remembering A LifeFuneral.com, Inc.
Immune suppression and inflammation
Research shows that people who are grieving have lower immune system function, and higher levels of inflammatory markers in their bodies — increasing the likelihood of illness or infection. Grief increases inflammation, which can worsen existing health problems or lead to new ones. Nebraska MedicineThe Wave Clinic
Digestive disruption
Chronic stress can induce changes to the gut microbiome and increase the permeability of the gut, causing bacteria normally contained within the gastrointestinal tract to leak outside of it — potentially activating further inflammatory responses. This is why grief can show up as nausea, reflux, changes in appetite, or foods that once felt fine suddenly causing problems. This is exactly what happened to me. UCLA Health
Sleep disruption
Sleep problems are among the most common physical effects of grief. Many grieving people struggle with racing thoughts and an inability to quiet their minds at bedtime. Insomnia prevents the body from experiencing the restorative effects of sleep, leading to brain fog, poor coordination, and changes in blood pressure. Nebraska Medicine
Fatigue and physical pain
The mental and emotional toll of grief can make even simple tasks feel overwhelming. This exhaustion is linked to stress hormone fluctuations and the body's struggle to process intense emotions. Immune cells release small proteins called cytokines, which increase the body's sensitivity to pain — which may explain the physical aching some people feel while processing grief.
Why pet loss hits the body so hard
One of the most painful aspects of pet grief is that it is often minimised by the world around us. People return to work. They expect you to move on. But the body doesn't follow social timelines.
When pet grief is unsupported, minimised, or rushed, the nervous system may remain in a state of alertness. When grief has nowhere to land, the nervous system holds it longer. The Cosmic Craft
Pets, particularly dogs, are known for their loyalty, affection, and unconditional love — qualities that make them deeply intertwined in our emotional lives. Attachment theory explains that humans naturally form strong bonds with relationships that offer companionship and comfort. Losing that bond is not a small thing. It is the loss of a co-regulator — someone who helped your nervous system feel safe every single day. Sweetgoodbyeforpets
What helped me — and what the research supports
I'm not going to give you a tidy list of five things that will fix this, because grief doesn't work that way. But I will share what supported my body through it:
Gentle movement, even short walks, to help process the cortisol. Nourishing food, even when appetite felt non-existent — the gut needs support during grief more than ever. Reducing stimulants like caffeine that were keeping my already elevated nervous system on edge. Rest without guilt. And perhaps most importantly — allowing myself to actually feel it, rather than filling every moment with noise to avoid the silence.
Healing from grief doesn't mean eliminating it. It means supporting the nervous system so it can safely process loss.
You are not falling apart. You are grieving.
If your body has been doing things that don't make sense since you lost your dog — please hear this. You are not weak. You are not "overreacting." Your body is responding, exactly as it was designed to, to the loss of a bond that was real, significant, and irreplaceable.
Grief lives in the body. Honouring that is the first step to moving through it.