How To Sleep Like A Caveman (Is 6 Hours Enough?)

Dr. Vandelar emphasizes that you cannot permanently change your chronotype; you can only override it temporarily. For evening types who struggle with early starts, the standard advice is to get up early and use a lot of light. However, he cautions that if the delay is large (e.g., naturally falling asleep at 3 AM but needing to be up at 7 AM), a simple morning light push is insufficient. Instead, he describes a structured chronotherapy approach: either moving the schedule backward (waking up 30 minutes earlier every two days with light at the new target time) or moving forward (going to bed 3 hours later each day until the desired bedtime is reached, using light upon waking at the shifted times). This forward-moving technique is particularly useful for adolescents with Delayed Sleep Phase Syndrome. Light lamps that emit 10,000 lux are clinically equivalent to outdoor light. He also mentions that light in the evening can push the clock later, which is useful for morning types who want to stay up later for social reasons. The key is to be consistent and use light precisely timed.

Dr. Vandelar defines Delayed Sleep Phase Syndrome as a condition where an individual's natural sleep onset is extremely late (e.g., 3-3:30 AM) and they cannot fall asleep earlier no matter what they try. This leads to chronic sleep deprivation, daytime sleepiness, concentration problems, and often tardiness at work or school. The common advice of just waking up early and getting light does not work for a 4-hour delay. He has used the forward-moving chronotherapy extensively in adolescents at a sleep medicine center. The protocol: on day 1, the person goes to bed at their natural time (3 AM). On day 2, they delay bedtime to 6 AM; day 3 to 9 AM; and so on, shifting 3 hours later each day. Upon each new wake time, they get bright light exposure to anchor the new rhythm. After 7-9 days, they 'circle the clock' and land at the desired earlier bedtime (e.g., 11 PM). This method is often more effective and faster than the backward approach, but it is intense. The backward approach (30 min earlier every two days) is gentler but may fail for large delays.

Dr. Vandelar addresses the scenario of being jolted awake—like Ben's blood glucose alarm story—where the body is thrust into an immediate state of arousal far from sleep. In such cases, the first priority is to de-arouse. He explains that many people worry about how long it takes to fall back asleep, but that worry itself is counterproductive. The more important goal is to become relaxed. If the arousal is too high, staying in bed can reinforce a stress reaction. Instead, he recommends getting out of bed and doing something that creates a good feeling and lowers heart rate and blood pressure, such as reading a book, watching a documentary, or doing a small puzzle—with no bright light. Only when one feels a genuine sense of sleepiness or deep relaxation should they return to bed. He distinguishes between being 'sleepy' and being 'relaxed': if you are relaxed and lying in bed with low arousal, that is perfectly fine even if sleep does not come immediately. Ben mentioned that he personally finds meditation apps like New Calm helpful for this, and Dr. Vandelar agreed that such sounds can work for mild arousal, but for very high arousal, getting out of bed is necessary.

Dr. Vandelar strongly advises against relying on commercial sleep trackers. He explains that these devices are 'completely unreliable' at determining which sleep stage you are in. Moreover, the scores they produce (like 72 out of 100) can induce significant anxiety, a phenomenon sometimes called orthosomnia. People who felt they slept great may see a low score and then feel tired because the device told them they should be. In contrast, a simple sleep diary—recording when you went to bed, when you woke up, and how restful you felt—is more clinically useful and does not introduce this anxiety. He references the fact that even actigraphy (a medical device) has a ~20-30 minute discrepancy compared to subjective report, meaning that objective data is not always more 'true' than perception. The goal is to understand your personal sleep need and pattern, which a diary over a holiday period can reveal naturally without technology.

Dr. Vandelar explains that the effect of napping depends entirely on your sleeper type. For someone with a healthy sleep system, a brief afternoon nap can be restorative—it sharpens cognition and mood without significantly impairing nighttime sleep. This is consistent with some ancestral patterns where the Hadza tribe nap on average once every two days, adding about 17 minutes of total sleep. However, for someone with insomnia, the reduced sleep pressure from a nap can lead to increased nighttime wakefulness, because the brain's adenosine-driven sleep urge is depleted. He also distinguishes between fatigue and sleepiness: many people with insomnia feel extremely fatigued but not truly sleepy. They mislabel this and may lie in bed for long periods expecting sleep, which only builds frustration. He notes that building sleepiness (via adenosine) requires being out of bed and active. This is why 'sleep restriction' is a component of CBT-I: temporarily reducing time in bed to boost sleep pressure. By contrast, in good sleepers, napping does not disrupt the robust sleep system.

Dr. Vandelar highlights that one of the major differences between traditional tribes and modern industrialized societies is sleep regularity. Tribal members adhere to very regular bedtimes aligned with natural light and dark cycles. In western society, the weekend sleep-in creates 'social jetlag', which disrupts the circadian clock and reduces sleep quality. He mentions a recent study showing that sleep consistency may even trump sleep volume for health outcomes. His advice: respect your personal circadian rhythm by maintaining a fixed sleep schedule. During holidays, when you can sleep without alarms, observe your natural rhythm to discover your personal chronotype and sleep need, then try to stick to that schedule as closely as possible during working weeks, using light therapy if needed to shift slightly.

Dr. Vandelar emphasizes the role of thermoregulation in sleep. The body's core temperature naturally drops in the evening as part of the circadian signal for sleep. Hot baths manipulate this: warming the periphery causes blood vessels to dilate, releasing heat and subsequently lowering core temperature once you get out and cool down. The critical timing is important—1.5 to 2 hours allows the full effect. He also notes that a heavy meal close to bedtime raises metabolic heat and digestive activity, counteracting this cooling process. He recommends finishing the last meal by 8 PM (or similarly giving at least 2 hours before bed), eating something light if hungry late, and keeping the sleeping environment cool. Ben mentions that his wife is a 'furnace' and he uses bed cooling devices, which aligns with this principle.

Dr. Vandelar explains that there are known processes regulating sleep: the circadian clock, sleep pressure (homeostasis), and a possible third process that helps consolidate sleep in the latter part of the night. The theory is that when you wake up to an alarm and then hit snooze, you drop into very light, fragmented sleep for 7-10 minutes, then wake again, over and over. This repeated breaking of sleep may actually strengthen the brain's drive to stay asleep, resulting in greater sleep inertia when you finally get up. Although direct research evidence is mixed, he leans toward recommending against snoozing. He contrasts this with protocols like NSDR (yoga nidra) that Ben mentions: those are restful wakefulness, not fragmented sleep, so they fit the 'awake but relaxed' philosophy and may be beneficial.

Dr. Vandelar addresses a question about whether masturbation to fall back asleep (à la Joe Rogan) has any scientific backing. He confirms that orgasms are indeed 'sleep-promoting' because they release a cocktail of hormones that facilitate relaxation and sleep onset. He notes that sexual activity with an orgasm is more sleep-promoting than without, and that the difference between partnered sex with orgasm and masturbation with orgasm is not large. The effect is more pronounced in men, likely because men achieve orgasm more consistently in heterosexual sex. This aligns with the broader sleep advice that relaxation and positive hormone release can aid sleep. He does not frame it as a primary insomnia treatment but rather as a behavior that physiologically supports sleep.

Dr. Vandelar points to studies on traditional tribes that live without artificial light or heating, whose sleep patterns likely mirror those of our ancestors 10,000–100,000 years ago. These people, such as the Hadza, show an average sleep duration of 6.2–6.5 hours measured by actigraphy, and they spend roughly 2–2.5 hours awake during the night. Crucially, they do not perceive this wakefulness as a problem—it is simply part of their normal night. The anthropologist research shows that in a typical night, there is less than one minute where every member of the group is asleep at the same time; someone is always alert, providing a sentry function against predators or other danger. Vandelar argues that this points to an evolved biphasic or polyphasic sleep architecture, and that modern anxiety about 'perfect sleep' has pathologised a normal biological pattern. A massive epidemiological study of 1.1 million people across the US, UK, and Netherlands found that being awake up to 20% of the night is entirely normal. He suggests that 'restful nights are more important than sleep'—if you are awake but relaxed and resting, it is not a health issue.

Dr. Vandelar traces the 8-hour rule to Robert Owen, a social reformer in Wales during the industrial revolution, who proposed an 'eight hours labour, eight hours recreation, eight hours rest' slogan as a humane alternative to brutal factory shifts—not a sleep science recommendation. In the modern era, Matthew Walker's popular book 'Why We Sleep' heavily promoted 8 hours as essential, but Vandelar notes that research published after the book demonstrates that being close to 7 hours, in the range of 6 to 8, is actually more associated with good health outcomes and is how people genuinely sleep. A large tri-national study found the average self-reported sleep is 7 hours, and only 10-25% sleep 8 hours or more. Vandelar suggests the 2015 National Sleep Foundation recommendation of 7-9 hours is a bit on the long side; the evidence base has shifted since then toward a wider normal range.

Dr. Vandelar discusses two main functions of dreaming. First, emotional processing: the amygdala (emotion center) is highly active during REM sleep, and dreaming helps reprocess daytime emotional experiences. Second, creativity and cognitive flexibility via bizarre dream content. He references neuroscientist Eric Hoel's theory that the surreal, non-logical nature of dreams acts as a kind of 'virtual reality' environment that prevents the brain's neural networks from becoming too specialized ('overfitted') to the regular patterns of waking life. By confronting the brain with odd, impossible scenarios, dreams force the system to remain plastic and capable of handling unexpected real-world challenges. Hoel's work further shows that when you make artificial intelligence systems 'dream' by injecting bizarre or off-pattern data, they become more intelligent and adaptive to changing environments. The human brain, as a 'supercomputer', benefits similarly. Vandelar notes that most people remember story-like dreams, which are typical of REM sleep, but dreaming occurs in all sleep stages. Suppressing REM with substances like cannabis or sleeping pills therefore disrupts both emotional processing and this creative flexibility.

Dr. Vandelar outlines that vulnerability to insomnia is not evenly distributed. Around 50% of the population has low sleep reactivity and can sleep well even under significant stress. The other 50% have high sleep reactivity, which is partly heritable—if a parent has it, the child is more likely to have it too. This trait means that life challenges (financial problems, marital issues, high workload) translate into hyperarousal and increased wakefulness at night, because the body interprets stress as a signal to stay alert for danger (an ancestral survival mechanism). He also notes that childhood trauma can elevate sleep reactivity, as the brain never developed a deep sense of safety, leading to hypervigilance at night. For these individuals, it is critical to treat insomnia early when it first appears, because early intervention produces much better outcomes. Standard CBT-I works for about 85% of patients, but the 15% who do not respond often have this high reactivity or unresolved trauma, and may need additional approaches like EMDR or body-oriented therapies.

Dr. Vandelar has personally delivered CBT-I to around 7,000-8,000 patients. He reports an 85% positive response rate. The 15% who do not respond well often have either high sleep reactivity or unresolved trauma. For those without trauma but who still struggle, he sometimes discusses medication with a physician—specifying that benzodiazepines are avoided because they suppress REM and deep sleep, while off-label options like mirtazapine or amitriptyline might be considered in a sleep center. For trauma-related cases, he recommends therapies like EMDR, which can address the underlying hypervigilance and safety deficits, or more body-focused relaxation therapies. He emphasizes the importance of catching insomnia early—the sooner after onset treatment begins, the better the result—especially for trauma survivors. He also stresses that the standard short-term insomnia advice (like staying awake to build sleep pressure) must be adapted for these complex cases.