Dr. Noam Sobel: How Smells Influence Our Hormones, Health & Behavior | Huberman Lab Podcast
Andrew Huberman・2 minutes read
Humans have a remarkable sense of smell that affects interactions, health, and relationships, with research exploring topics from olfactory regeneration to chemosignaling and body odor. The complex interplay of scents, emotions, hormones, and behavior underscores the importance of olfaction in human life.
Insights
- Humans have a strong sense of smell comparable to dogs, allowing them to sense the chemical world around them.
- Tears from others can significantly affect hormone levels.
- Trauma, especially to the back of the head, can lead to a loss of the sense of smell due to damage to the olfactory nerve.
- Loss of smell, especially due to conditions like COVID, can be distressing, with a general rule suggesting that if smell isn't regained within a year to a year and a half, recovery is unlikely.
- Olfactory training, involving intentional and constant exposure to various scents, has shown success in aiding olfactory recovery, potentially more effective than alpha lipoic acid.
- The alternating airflow through nostrils may reflect autonomic nervous system balance, with potential implications for control through practices like yoga.
- The debate over the study's replication and results highlighted the complexities of scientific research, with disagreements over methodology and interpretation leading to rebuttals and further investigations.
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Recent questions
How does the sense of smell impact human interactions?
The sense of smell plays a significant role in human interactions, influencing stress levels, hormone levels, and subconscious brain functions. Humans have a strong sense of smell comparable to dogs, allowing them to sense the chemical world around them. Interacting with others involves exchanging chemicals, and tears from others can significantly affect hormone levels. Research has shown that individuals are constantly sensing their own odors, which can influence cognition and behavior. Olfaction involves receptors in the olfactory epithelium, transducing odorants into neural signals via the olfactory nerve to the olfactory bulb. Overall, the sense of smell is a powerful tool that impacts various aspects of human communication and relationships.
Can the sense of smell be lost permanently?
Loss of the sense of smell can occur due to various factors, including trauma, neurodegenerative diseases, or conditions like COVID-19. Trauma, especially to the back of the head, can lead to a loss of smell due to damage to the olfactory nerve. Complete severing of the olfactory nerve results in permanent loss, as sensory neurons typically do not regenerate in adult humans. However, partial severing or retention of some nerve tissue post-injury increases the chances of recovery due to neuron growth along existing pathways. Studies have shown that if smell isn't regained within a year to a year and a half, recovery is unlikely. Certain treatments like alpha lipoic acid have shown potential in accelerating smell recovery, but the loss of smell can be distressing and have long-term implications for an individual's quality of life.
How does the nasal cycle affect human physiology?
The nasal cycle involves alternating airflow between nostrils every two and a half hours on average, reflecting the autonomic nervous system's balance. This cycle is linked to the state of alertness or sleepiness of an individual. The alternating airflow through nostrils may have implications for autonomic nervous system balance, with potential effects on practices like yoga. Studies have shown that nasal breathing can shape cognition, modulate neural activity, and potentially influence brain functions. Additionally, a wearable device called the nasal halter has been developed to measure nasal airflow as a potential disease marker, distinguishing between ADHD and non-ADHD adults. Overall, the nasal cycle is a fascinating aspect of human physiology that can impact various bodily functions and behaviors.
How does olfactory training aid in smell recovery?
Olfactory training involves intentional and constant exposure to various scents and has shown success in aiding olfactory recovery. Studies suggest that olfactory training may be more effective than treatments like alpha lipoic acid in regaining the sense of smell. Participants in studies involving olfactory training have shown improvement in tracking odors and speed in tracking scent trails. Olfactory neurons are unique in their ability to regenerate in adult mammals, and olfactory training may stimulate this regeneration process. The training can help individuals differentiate between different scents, improve their ability to detect odors, and potentially enhance their overall olfactory function. Overall, olfactory training is a promising method for individuals looking to recover their sense of smell.
How does body odor influence human relationships?
Body odor plays a significant role in human relationships, influencing attraction, comfort, and social bonding. Research has shown that individuals imprint on specific scents, creating strong emotional connections and feelings of comfort. Studies on aggression and chemosignaling have revealed molecules like hexadecanal that can promote social bonding and reduce aggression. Human studies have demonstrated that body odor similarity can predict friendship and contribute to building relationships. The concept of "click friendships," immediate deep connections between individuals, has been linked to similarity in body odors. Overall, body odor can impact personal preferences, relationships, and social interactions, highlighting the complex interplay between scents and human behavior.