The best sleep schedule (according to science) isn’t just “8 hours”, it’s timing + consistency.
In this episode, Dr Karan Rajan speaks with Professor Gina R. Poe about how to build a sleep schedule that supports deep sleep, REM sleep, memory, and long-term performance, using the levers that actually move the needle: consistent timing, light exposure, temperature, naps, and meal timing.
In this conversation, we cover:
Why sleep consistency is repeatedly linked with performance and healthier ageing outcomes
A practical “best schedule” window (and why earlier sleep helps catch key deep-sleep biology)
How light at night disrupts circadian timing (and why dim red light matters)
Naps: when they help, and when they can backfire on night sleep
Temperature and why overheating can reduce REM sleep
Meal timing (“chrononutrition”) and why late meals can fragment sleep
Plus: REM sleep, sleep spindles, memory, alcohol, and why some sedatives alter sleep architecture
🎬 Chapters
01:03 – Introducing Professor Gina R. Poe
01:51 – REM sleep: remembering AND forgetting
02:15 – Crick’s REM-for-forgetting hypothesis
04:16 – Hippocampus → neocortex: how memories move during sleep
06:06 – Stress “sweet spot” for learning (too little vs too much)
07:39 – Rats in space: learning in 3D/zero gravity
11:26 – Locus coeruleus (“blue spot”): arousal, learning, and REM switching
14:26 – Nightmares/PTSD: why REM needs the LC to go quiet
17:33 – Alcohol + sedatives: how they can reduce spindles and REM
18:47 – Sleep architecture 101: cycles, deep sleep, REM, spindles
20:48 – Growth hormone timing + why circadian alignment matters
21:27 – “You can’t catch up”: why your body has a schedule
23:17 – Transition into REM: spindles, K-complexes, P-waves
25:53 – How to increase spindles: learning something new
27:32 – What reduces spindles: sleeping pills/benzos/alcohol
28:29 – Wearables vs EEG: what tracking can and can’t tell you
31:27 – Wearables + alcohol effects + women & temperature tracking
33:19 – Hormones & sleep: what we know, what’s inconclusive (and why)
36:59 – New parents: shifts, feeding timing, and protecting circadian rhythm
40:15 – Night feeds: don’t turn on bright lights (use dim red light)
41:29 – The best sleep schedule (science-based): consistency + timing
43:38 – Naps: when they help and when they hurt bedtime
44:42 – Temperature: why overheating can reduce REM sleep
47:28 – Meal timing: avoid late meals + use meals to reset jet lag
49:16 – The research gap: women’s cycles, diaries, and better studies
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About Dr Karan:
Dr. Karan Rajan is a doctor, author, and educator dedicated to making health and medical science accessible to all. Through evidence-based analysis, he addresses topics such as gut health, brain health, and healthy lifestyle choices, while dispelling common medical myths with a touch of dark humor.
📱Connect with me:
Instagram: / drkaranrajan
Facebook: / drkaran
TikTok: / dr.karanr
X: / drkaranrajan
Website: www.drkaranrajan.com
#SleepScience #CircadianRhythm #SleepSchedule #REMSleep #DeepSleep
Ireland