Eight Sleep sat down with Peter Attia M.D. - preeminent longevity expert - to discuss his philosophy on sleep and his new book: "Outlive: The Science and Art of Longevity." Peter is a longtime friend of Eight Sleep and we're excited to help celebrate his book launch through this exclusive interview. More on "Outlive": https://peterattiamd.com/outlive/
What was the greatest challenge in writing the book? What was the most gratifying aspect of the process?
An incredible amount of research went into this book, and over the six years I spent writing it, that research was always changing and evolving. While this necessitated several rounds of rewrites, it also meant that I was constantly reassessing my thinking about each topic, which helped me to achieve deeper understanding for myself as well as to craft better explanations for readers.
Why was it important for you to include a chapter on sleep in your upcoming book?
Sleep needs to be a part of any discussion of living longer and better. It is one of the five pillars that we think about with respect to modifiable behaviors that can improve the length and quality of life.
Your relationship with sleep & current routine
Like most people, I never thought much about sleep as I was growing up. Then during my time in medical school and residency, I took it as a point of pride that I could sleep less than others and still perform (or so I thought). Even after leaving medicine to work in consulting, I believed that sleep was something to do when you’re dead. But that view changed dramatically around 2012 after I confronted data on this subject and began to understand how sleep is conserved evolutionarily across species. Since then, getting enough sleep of high quality has been a priority.
Unfortunately, in pursuing residency, I didn’t have much choice when it came to when I slept or for how long, so I wouldn’t want to go back and talk to my med school self. The discussion would have been awful because the only advice I could have given him at that point would be to leave medicine, in which case I wouldn’t be doing what I am today.
Peter's ideal bedtime routine consists of a few key components
Which of these components do you think has the greatest impact on your sleep quality?
It’s hard to choose, but I’d say that elimination of alcohol and avoidance of eating within 3 hours of bedtime have the most profound impacts. Violating those two can destroy any positive impact that the others may have. Sauna is probably the least critical on this list – it’s nice to have but isn’t essential.
Why is the “wind down” part of a routine so important?
After alcohol and eating before bedtime, stimulation – from stressful work emails or other sources – close to bed can also be catastrophic and is probably next on the list of hazards when it comes to sleep. Wind-down is critical. It turns my brain off and helps me calm my ruminating mind in order to prepare for sleep.
Peter's tips for finding a personal routine
Start with the basics of sleep hygiene: a dark, cool room, consistent bedtime, and avoiding food and alcohol for hours before bed.
Eight Sleep (why temperature and tracking matter)
I love using Eight Sleep. I’ve tried several different mattress-cooling products and have found Eight Sleep to be the best because it allows me to control the temperature more clearly and at variable levels throughout the night. It’s also very quiet and hassle-free – no leaks or other issues I’ve experienced with other products. Frankly, it gets cooler as well. All in all a great product.
Also relating to temperature, I try to create a large temperature gradient between the heat of the sauna and the cool of my bed because we understand that this gradient and temperature drop is important for driving sleep.
Why does temperature matter so much for our sleep quality?
We have a fairly clear sense now that the body cools as we go to bed, hitting a nadir probably in the early part of the morning before warming as we wake up. The body has different temperature ranges for comfort between waking and sleeping, and we tend to sleep better in cooler environments, which appear to reduce sleep onset time and increase REM sleep.
Body temperature changes over the course of the day and night, so the ambient temperatures at which we are most comfortable also fluctuate. Sleep experiments have generally shown that relatively warm environments in the earlier half of the night compromise sleep, whereas a mild increase in temperature in the latter part of the night is less disruptive to ongoing sleep as body temperature starts to rise. This seems to be part of the process by which the body prepares for wakefulness, so scheduling temperature transitions makes it possible to create a cool environment early in the night to promote sleep and a warmer environment in the morning to aid the body in preparing for wakefulness.
Generally speaking, sleep trackers are useful for monitoring heart rate and heart rate variability, from which we can get a sense of various aspects of sleep quality. I’ve found it helpful in seeing how adjustments to my sleep routine translate into sleep quality, which overall has helped me to settle on a regimen that works best for me. At this point, I have a fairly good sense of what the sleep tracker is going to say before I look at it, so although I still typically track my sleep, I find it mostly just validates my subjective assessment.
On your podcast, you cite that perception of sleep quality can impact a person’s performance. Can you say a bit about the importance of how our psychology impacts our sleep?
In various studies, one group of subjects received false feedback that they’d slept poorly, while a control group was given positive (accurate) feedback on sleep quality. Interestingly, even though true sleep quality was equivalent between groups, those who were told they’d slept poorly performed worse in cognitive tests and reported feeling more tired than those who were given accurate sleep feedback. These results indicate that quantitative feedback about sleep quality (such as from sleep trackers) is more than just documentation – it can actually influence our behavior and psychology in potentially detrimental ways.
For many people, sleep trackers can be very helpful from a motivational aspect. The knowledge that your sleep quality is being monitored can provide extra motivation to follow healthy sleep habits because you want to get a good score each night. But it’s important to recognize that sleep feedback is a tool, not a goal in itself, and when the tool isn’t useful or does more harm than good, it’s time to put it aside. So if I’m sick or have had a couple of glasses of wine before bed and know that I’m going to have a bad night of sleep, I take my sleep tracker off because the inevitable negative feedback will only exacerbate the effects of poor sleep.
Broadly, why does sleep matter so much?
The easiest way to think about this is to consider what goes wrong when a person isn’t sleeping well. Evidence shows very definitively that a lack of sleep increases insulin resistance and compromises performance. In the long-term, it also appears likely to increase risk of cardiovascular disease and neurodegenerative disease, and even in the short-term, I suspect that it also reduces distress tolerance and one’s ability to manage the day-to-day stressors of life.