My guest is WHOOP Director of Analytics, Emily Capodilupo. Emily is a published author who’s specialized in sleep for nearly a decade, ever since her freshman year at Harvard.
Emily and I discuss her background and role in WHOOP becoming an industry leader in sleep tracking, as well as several new features we’ve released this month to help you better understand and optimize your sleep.
We also take a deep dive into answering many sleep-related questions from our members–from learning more about the stages of sleep, to improving your sleep environment and falling asleep faster, to how exercise and strain relate to sleep, to even whether trying to sleep eight straight hours should really be the norm in the first place.
No matter who you are, we can all benefit from better sleep and I think this podcast has something for everyone.
3:46 – Focus on Sleep. Emily speculates on how amazing it is that we’ve always known so little about why we sleep. “It’s really cool to do research on something that you experience.”
7:41 – Joining WHOOP. “The ability to have really high impact and unlock information for people that’s there for the taking. … There was so much opportunity to make a really big difference.”
10:48 – Turning Physiology into WHOOP Metrics. In a study of college athletes, “we found that the [WHOOP] recovery score predicted how they would perform that day better than what other people were using at the time.” WHOOP recovery factors in resting heart rate, HRV, and sleep. “We were able to combine them in a unique way that had never been done before that created something more useful.”
15:30 – Top 100 Sleepers on WHOOP. How did we determine them and what did we learn? “These people are not doing anything that you can’t replicate.”
20:01 – Bedtime Routine. “Creating that moment of separation between day and night.”
20:48 – Sleep Consistency. “If I went to bed at 9 o’clock yesterday, how close to 9 o’clock did I go to bed today? … Do you have a stable sleep/wake pattern?” A 2017 study showed that “sleep consistency was able to predict academic performance.” By examining WHOOP data, we found the same was true for athletic performance.
24:18 – New Sleep Features for WHOOP members. In addition to Sleep Consistency, we’ve also added Sleep Efficiency and Respiratory Rate.
31:39 – Low Recovery Despite Good Sleep? Emily explains what other things factor into recovery. “Even people who are pretty in tune with themselves, your body knows more than you do.”
36:30 – Does a Bad Night of Sleep Carry Over beyond the next day? What about a very good one? Catching up on sleep on the weekends “really doesn’t work.” She likens sleep debt to your credit score.
40:56 – Too Much Sleep? “You can’t stockpile sleep. … Once you’ve met your body’s need and you’re no longer at all sleepy it’s just a waste of time.” There’s a point of diminishing returns where more sleep isn’t better. “Typically the first part of sleep tends to be more efficient,” so the longer you sleep the less efficient your sleep usually becomes.
43:29 – More REM & Slow Wave Sleep. “There is a relationship between sleep consistency and slow wave and REM sleep. … We think that’s because when your body is anticipating sleep it knows what to do.”
44:54 – Staying Asleep. “Is your environment conducive to sleep?” Emily lists a number of things that help you avoid getting woken up.
45:59 – Sleep Products she likes. “Custom-fit blackout shades in every bedroom” is something she recently installed. “Our circadian rhythms are essentially set by light. If you have as little as 80 lux of light in your bedroom you’re telling your body it’s daytime.” Bose sleep buds with snoring noise cancellation are another thing Emily recommends.
50:04 – Back, Side or Stomach? “Sleeping on your left side is supposed to be good for digestion.”
51:07 – Snoring a Bad Sign? “One of the best indicators of snoring is weight.” Wedge pillows and rolling over to your side can help with snoring, as can a humidifier, mouth guards or Breathe Right strips. If nothing works, see a doctor.
52:58 – Strain’s Effect on Sleep Cycles. “People who had really low day strain had worse sleep efficiency.” But also, “if you exercise really, really hard, that can make it harder to sleep at night.”
55:08 – You Get Stronger During Sleep, not when you’re at the gym. “We produce 95% of human growth hormone during slow-wave sleep, so you need to give yourself that opportunity to sleep in order to recover.” If you don’t get a lot of sleep the night after a hard workout, “that’s where you’re leaving the most potential gains on the table.”
57:15 – Exercise in Morning or Evening? “The average workout 4 hours before bedtime did not have an impact on sleep efficiency.”
58:28 – Sleep Stage Balance. “Your body kind of knows how to allocate it’s sleep time. REM sleep is the mentally restorative part of sleep, and slow wave, or deep sleep, is the physically restorative part of sleep. Your body is going to allocate time between slow-wave sleep and REM sleep based on what it feels the needs are.” Typically slow wave occurs before REM, so lack of REM sleep can be a sign of sleep deprivation.
1:00:03 – HRV During Sleep. “When you don’t have true slow-wave sleep sometimes you’re in ‘almost’ slow-wave sleep.” WHOOP tracks your HRV during your deepest sleep each night.
1:00:58 – Night-Shift Work. “The best thing you can possibly do is to try and maintain that schedule.” Emily also recommends taking melatonin to help fall asleep (although it won’t help you stay asleep).
1:04:26 – Sleep Supplements. She suggests magnesium and zinc, but only if you’re deprived of either. “All the FDA cares about is that they’re safe to consume, not that they’re at all potent.” Even though two different brands contain the same amount, they might not be equally good at getting into your bloodstream. “Do the research to find out where they are from … make sure they are a bio-available form.” Emily uses Nature Made melatonin.
1:08:45 – Is 8 Straight Hours Really Best? “Charles Dickens wrote about first sleep and second sleep in the 1840s.” The industrial revolution is likely the cause for why we now usually sleep roughly 8 hours in a row. A study in 1992 by Thomas Wehr showed people naturally tended to sleep 4 hours, wake up for a bit, then sleep 4 more.
1:11:44 – Naps. “Napping is a great way to reduce sleep debt, but not all naps are created equally.” Emily describes the value of “caffeine naps.”
1:13:19 – Changing Time Zones. “If you’re only going away for a few days or a weekend, just stay on your own time zone.” In the new time zone, “getting as much day-time light exposure as possible is going to help your circadian rhythm.”
1:15:25 – Dangers of Ambien. “Woman respond to Ambien way stronger than men do … sometimes you sleep walk or sleep talk and act out your crazy dreams.”
1:17:09 – Nutrition for Sleep. Heavy and fatty foods at dinner can be problematic. “There are a lot of foods we can eat at dinner that can be sleep promoting.” Dairy products in particular. “Getting your core [body temperature] warm so it can cool off helps you fall asleep.” Tart cherry juice also has melatonin.
1:21:06 – Hydration Before Bed? “Being dehydrated can cause all kinds of stress responses and inefficiencies that will show up in your sleep.” But, you also don’t want to make yourself have to get up to use the bathroom.
1:21:53 – Alcohol’s Effect on Sleep. “If your blood alcohol content has returned to zero, it’s going to have less of an effect on your sleep.” What does WHOOP data look like when you’re sleeping drunk? Your heart rate is very high, and you don’t hit the restorative stages of sleep until you become sober.
1:23:19 – What are Sleep Disturbances? “Brief periods of being awake that are typically so short that we’re not aware of them.” People average about 9 per night. “They can account for a significant amount of wake time.”
1:25:44 – Not Dreaming? “We predominantly have our most intense dreams during REM sleep. … We tend to have the boring dreams during light sleep and the fantastical dreams during REM sleep.” If you wake up during slow-wave sleep when you’re not dreaming, you don’t remember and often think you didn’t dream at all.
1:27:21 – Socks. Having warm toes can be sleep promoting.
1:27:59 – WHOOP Now Incorporates Your Daily Sleep Survey Responses. “I learned that when I drink, I get 30% less REM sleep than when I don’t.”
1:28:55 – Average WHOOP User Sleep Stats. “In the first 129 days on WHOOP, on average users spend 41 more minutes in bed.”