The olfactory system connects the nose directly to the brain—and affects more than scent alone.

When we think about health, recovery, or resilience, smell is rarely at the top of the list. Yet the olfactory system is one of our oldest sensory systems—and one of the most directly connected to the brain. Scent information travels straight to the limbic system, shaping memory, emotion, motivation, and our sense of safety.

That direct connection is why a familiar scent can instantly change how we feel. And it’s also why changes to smell can affect far more than we expect.

For people living with Long COVID or other infection-induced chronic conditions, changes to, or loss of, smell are common. While this can feel secondary to symptoms like fatigue, brain fog, or pain, it’s not something to ignore. The olfactory system plays a quiet but important role in appetite, mood, pain regulation, health, and overall brain function.

Connections With Smell

Smell supports several important functions in the body and brain. It helps prepare the digestive system so nutrients can be used more efficiently. It also influences how the brain processes pain and plays a role impacting our emotions and how we present ourselves to the outside world. When their sense of smell is reduced or lost, people often notice changes in mood, and low mood or depressive symptoms are more common.

Changes in smell are also linked to overall brain health. In some neurological conditions, changes to the sense of smell can appear early, long before other symptoms. This doesn’t mean loss of smell equals disease—but it does tell us that the olfactory system is closely connected to neural function.

With COVID infections, research shows that cells involved in sending smell signals to the brain can be directly harmed by the virus or by inflammation. This likely explains why so many people experienced changes to, or loss of, smell during and after infection. Smell is affected, but also the areas of the brain the virus could reach directly through the nose can experience damage. 

The encouraging truth is that the olfactory system – including the nose, different parts of the brain, and the connections between them – is adaptable. It can be trained and retrained. Olfactory training is an effective approach: twice a day, gently smelling a few different types of scents—such as floral, sweet, umami, and spicy—without forcing recognition or intensity.

The goal is to give the brain regular, safe sensory input. Over time, this repeated input can support neuroplastic re-engagement—helping existing smell pathways function more effectively again. This supports the sense of safety, which is crucial to reduce symptoms or inflammation.

The bigger takeaway is this: every system in the body has a role in health and resilience. When we support these systems—one by one—the brain and body have a better chance to adapt, stabilize, and function well again. 

Warmly,
Katie & Andrea

PS: If you’ve noticed changes in smell or taste since illness, you’re not alone. Supporting sensory systems is one of the ways we help people rebuild steadier brain-body function across ThriveNinety programs, always with safety, accessibility and pacing in mind.