Uploaded October 2025 | Updated September 2026, 3 weeks ago
In this episode, I speak with Professor Guy Leschziner, a consultant neurologist and leading sleep specialist who has spent over a decade as the clinical lead at one of Europe's largest sleep disorder centers.
Drawing on insights from neuroscience, clinical practice, and evolutionary biology, Guy explores the fascinating world of sleep—from its biological functions to its profound impact on our physical and mental health.
Expect to learn:
— Why studying the extremes of human behavior helps us understand normal brain function
— How sleep affects everything from immune function to cognitive performance
— The surprising way our brain's "glymphatic system" cleans toxins during deep sleep
— Why insomnia treatments like CBT-I are so effective and how they work.
And more.
You can learn more about Guy's work at https://www.guyleschziner.com.
—
Guy Leschziner, Ph.D., is a neurologist specializing in sleep disorders and epilepsy, serving as Consultant Neurologist at London Bridge Hospital and Clinical Lead for the Sleep Disorders Centre at Guy’s and St Thomas’ Hospital, one of Europe’s largest sleep units. He is also Reader in Neurology at King’s College London’s Institute of Psychiatry, Psychology and Neuroscience. Dr. Leschziner is the author of The Nocturnal Brain, The Man Who Tasted Words, and The Seven Deadly Sins, and has presented sleep-focused series for BBC Radio and Channel 4.
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Timestamps:
00:00 - Intro
01:39 - Why Extreme Human Cases Matter
02:40 - The Strangest Sleep Disorders
04:27 - The Bizarre Case of Kenneth Parks
05:44 - What Your Brain Does While You Sleep
08:45 - When Sleep Becomes a Legal Issue
10:36 - Why We Really Need Sleep
11:43 - How Sleep Cleans the Brain
13:42 - What Happens When You Don’t Sleep Enough
15:25 - Why Evolution Made Us Sleep
17:04 - How the Brain Sleeps in Halves
19:35 - Habits That Ruin Your Sleep
22:18 - The Foundations of Great Sleep
25:33 - Training Your Brain to Sleep Better
28:02 - Reprogramming Your Sleep
29:06 - How CBT Can Cure Insomnia
31:38 - How Sleep Shapes Your Mind
32:56 - Why Modern Life Destroys Sleep
35:03 - The Power of Your Body Clock
37:29 - How Light Controls Your Sleep
38:56 - Why Our Body Clock Exists
40:41 - How the Blind Experience Sleep
42:53 - Are You Born a Night Owl or Early Bird?
44:22 - The Truth About Chronic Pain
47:54 - Pain Without Injury — How It Happens
49:04 - Should You Take Melatonin?
50:38 - The Science of Perfect Wake-Up Timing
52:14 - Real Hope for Insomnia Sufferers
54:48 - The Biggest Myths About Sleep
56:58 - Final Thoughts
--
Interview Links:
— Guy’s website: guyleschziner.com
— Guy’s book: amzn.to/3VvTnb6
In this episode, I speak with Professor Guy Leschziner, a consultant neurologist and leading sleep specialist who has spent over a decade as the clinical lead at one of Europe's largest sleep disorder centers.
Drawing on insights from neuroscience, clinical practice, and evolutionary biology, Guy explores the fascinating world of sleep—from its biological functions to its profound impact on our physical and mental health.
Expect to learn:
— Why studying the extremes of human behavior helps us understand normal brain function
— How sleep affects everything from immune function to cognitive performance
— The surprising way our brain's "glymphatic system" cleans toxins during deep sleep
— Why insomnia treatments like CBT-I are so effective and how they work.
And more.
You can learn more about Guy's work at https://www.guyleschziner.com.
—
Guy Leschziner, Ph.D., is a neurologist specializing in sleep disorders and epilepsy, serving as Consultant Neurologist at London Bridge Hospital and Clinical Lead for the Sleep Disorders Centre at Guy’s and St Thomas’ Hospital, one of Europe’s largest sleep units. He is also Reader in Neurology at King’s College London’s Institute of Psychiatry, Psychology and Neuroscience. Dr. Leschziner is the author of The Nocturnal Brain, The Man Who Tasted Words, and The Seven Deadly Sins, and has presented sleep-focused series for BBC Radio and Channel 4.
--
Timestamps:
00:00 - Intro
01:39 - Why Extreme Human Cases Matter
02:40 - The Strangest Sleep Disorders
04:27 - The Bizarre Case of Kenneth Parks
05:44 - What Your Brain Does While You Sleep
08:45 - When Sleep Becomes a Legal Issue
10:36 - Why We Really Need Sleep
11:43 - How Sleep Cleans the Brain
13:42 - What Happens When You Don’t Sleep Enough
15:25 - Why Evolution Made Us Sleep
17:04 - How the Brain Sleeps in Halves
19:35 - Habits That Ruin Your Sleep
22:18 - The Foundations of Great Sleep
25:33 - Training Your Brain to Sleep Better
28:02 - Reprogramming Your Sleep
29:06 - How CBT Can Cure Insomnia
31:38 - How Sleep Shapes Your Mind
32:56 - Why Modern Life Destroys Sleep
35:03 - The Power of Your Body Clock
37:29 - How Light Controls Your Sleep
38:56 - Why Our Body Clock Exists
40:41 - How the Blind Experience Sleep
42:53 - Are You Born a Night Owl or Early Bird?
44:22 - The Truth About Chronic Pain
47:54 - Pain Without Injury — How It Happens
49:04 - Should You Take Melatonin?
50:38 - The Science of Perfect Wake-Up Timing
52:14 - Real Hope for Insomnia Sufferers
54:48 - The Biggest Myths About Sleep
56:58 - Final Thoughts
--
Interview Links:
— Guy’s website: guyleschziner.com
— Guy’s book: amzn.to/3VvTnb6
