Hunter-gatherers sleep like me

Anthropologists Gandhi Yetish, Hillard Kaplan and their colleagues just published the results of some experiments that show hunter gathers get much less sleep than the eight hours we supposedly need. In fact, their sleep patterns closely resemble mine, despite the conventional wisdom that my average 6.5 hours per night is too little.  (There’s a nice summary by Anahad O'Connor in a New York Times Blog post)

A long-time fan of Zeo, I have carefully measured my sleep for many years and I know that my lifetime average is pretty close to 6.5 hours. That’s real sleep, measured by a brain wave detector strapped to my head. Like other lazy people, I sometimes lay in bed longer than that, but it’s a rare occasion when my sleep duration is longer than 7 hours, even when I’m loaded with potato starch to grow serotonin-helping bifidobacterium.

Because the new study appears to contradict the rest of conventional scientific wisdom about the importance of 8+ hours of sleep, I read it carefully, along with the data collected to see if I could spot any problems.  So far I think everything adds up:

Plenty of participants:  100 people, spread among male/female at different ages, including some fairly old: 60+

Three separate, unrelated societies: from both Africa and South America, it’s hard to argue these people are somehow related at anything other than being hunter-gatherers.

Week-long observations: You might want a study like this to go on for weeks or years, but I think the duration, from a week to a month per person was just fine. 

Good self-tracking hardware: the anthropologists used the Philips Actiwatch 2, strapped to subjects’ wrists with a tamper-proof hospital band. These are well-studied, medical-grade wearables and although they use actigraphy information, not perfect because it’s based on movements in the night, if anything these devices tend to overestimate the amount of sleep. I skimmed the data from the study and it looks good.

The authors conclude that ambient temperature, not daylight, is the most important signal that tells these hunter-gatherers it’s time to sleep. They note that these people sleep no the ground on skin mats, inside huts or in the outdoors, often covered with lightweight cotton blankets. This isn’t all that different from camping, when I tend if anything to sleep more. 

Interestingly, when Zeo studied 5000 of their users back in 2011, they found an average sleep time of something closer to 8 hours, with my 6.5 hours falling out of the 95% confidence interval, making me (and the hunter gatherers) real outliers.

Note that although I rarely sleep longer than 6.5 hours, I feel great in the morning and I’m generally alert and feel reasonably fresh all day. Like the hunter-gatherers, I don’t nap and I rarely suffer from insomnia.

I’ll be watching the follow-ups to this research carefully but for now I’ll be much more satisfied that my current level of sleep is just fine.

 

 

 

 

 

[book] The Gluten Lie

Most people will think Alan Levinovitz, a Professor of Religion, an unlikely author of a diet book, particularly one like this that refutes many of the most popular diet fads. But in fact it’s one of the best health books I know. Nobody should read a diet or health book without reading this one first.

In my half-century of life, I can remember science being applied to so many different health claims that I’ve forgotten all the now-discredited ones that were once popular, but Levinovitz provides some reminders. Take MSG, for example, which began its road to public vilification with a letter to the editor of New England Journal of Medicine by a doctor who had a bad experience at a Chinese restaurant. Throughout the 1970s it was implicated as the cause of so many ailments that it became the subject of much serious scientific inquiry that all turned up negative. To this day, many people are convinced MSG causes headaches, yet no well-designed study has ever found any difference between MSG and a placebo.

MSG, like gluten and most of the other substances that have come and gone in the public favor, is a nocebo, an inert substance that causes harm because of the expectation of harm, not from anything real. On and on it goes with many other embattled foods. Wheat gluten is just the latest, most popular example, following in the footsteps of a whole line of defamed foods: salt, cholesterol, red meat, soy, and on and on.

Part of the problem is that, for many substances, there really are some people who are negatively affected. Celiac Disease is real for some people, just as sugar is a problem for diabetics and lactose causes stomach distress for many. But just because something negatively affects some people doesn’t mean it’s bad for the rest of us.

Levinovitz’ religious studies background makes him uniquely qualified to see the parallels between various health claims and religious belief. Claims about food are often couched in terms that, with a slight tweak of terminology, would be entirely appropriate coming from a church pulpit. Here are some examples:

You are what you eat: this idea can be traced to Galen, but it’s still in us. It’s why it’s so easy to sell the American public on the idea that eating fat makes you fat. Similarly, it’s not hard to convince some people that meat-eating, and its association with killing of animals, will make you more likely to be cruel to other humans.

If it tastes good it must be bad. It’s not hard to see the Puritan streak in much of the American discussion of the dangers of processed foods. We like the taste of sugar too much, leaving us at the mercy of Evil Corporations (Satan) who exploit our innocent addictions (The Fall) in order to make Big Profits. The truth, unfortunately, it more complex.

The monotonic mind. Religious people are comfortable with black and white conditions. To an Orthodox Jew, pork is 100% bad. The only optimal amount of coffee to a Mormon is zero. But with health, the rules are more complex. A glass of wine at a meal can be healthy for many people, but any positives go away quickly if you drink too much. Food is rarely if ever a black and white health vs unhealthy situation. The dose makes the poison. 

Levinovitz gives many more interesting examples, including critical comments about Bulletproof’s David Asprey, Chris Kresser, and even Gary Taubes. Few diets or diet gurus are 100% bad, of course, and that’s why many will find the book frustratingly difficult to pin down. There’s a little something critical for everyone.

The most entertaining part of the book was the final two chapters, helpfully printed on darker paper to make it stand out. Levinovitz invents an entirely new diet fad, written uncritically in the first part, and then overwritten with his own comments in the second. At first, you’ll be tempted to think Levinovitz’ book is just like so many other diet books, which go into detail taking down other ways of eating, only to return with the One True Diet. But that’s why the second part is so interesting: as he might do with religious commentary, Levinovitz picks apart each of his own dietary claims to show how deceptive they are, how they fit into well-worn patterns, and why you shouldn’t be fooled.

That said, the book does offer one piece of dietary wisdom, but sadly it’s not the one most people are primed to hear. Moderation.  Period. Don’t eat too much.

Perhaps not a satisfying conclusion to some people, but perhaps that’s to be expected when you take all the religion out of eating.

Zocdoc vs OpenTable

The idea behind ZocDoc is brilliant: a modern, super-easy web site that lets you book a doctor appointment as easily as OpenTable lets you book restaurant reservations. ZocDoc knows each doctor’s specialties, which ones take which insurance plans, their location, and — the best part — which times are available for appointments. Go to one web site, enter your information, and immediately doctors in your neighborhood that meet your requirements. Find one you like, book the appointment, and that’s it!

That’s what’s supposed to happen, but unfortunately the inanity of the American healthcare system gets in the way, and today was the second time I’ve been unhappily surprised at the results.

The front end works fine. I entered my information and quickly found a list of doctors in my area that meet my requirements, including availability times. I hit submit and that was it: a nice, professional confirmation for a visit with a doctor with good reviews. They even added the appointment automatically to my iPhone calendar, and offered to text me a reminder before the visit. ZocDoc already knows my insurance and basic health information, so I didn’t even need to fill out additional forms for the visit. Perfect!

Unfortunately, that’s as far as the resemblance to OpenTable restaurant reservations ends.  I had scheduled my appointment for 1pm, right after lunch in the area close to where I knew I was going, but early on the day of the appointment I received an odd email from a different doctor confirming my appointment for 11am. The ZocDoc site knew nothing about this, so I called the new doctor to see what was happening.

The new doctor’s receptionist was confused too. From her point of view, I had made an appointment at 11am. If I didn’t show up on time, or if I canceled the appointment less than 24 hours beforehand, she would charge me a fee. The fact that I had booked it through ZocDoc — and that I had a different time confirmed — was not relevant to her.

Well, I shifted things around so that I was able to make the 11am appointment, but frustratingly, when I arrived I had to fill in all the forms (again). A cheerful physician’s assistant brought me into the exam room, took my vital signs and then, almost as a side comment, warned that my insurance company probably wouldn’t reimburse me for today’s visit.  What!?

By then, it was really too late for me to get up and walk out the door. The doctor arrived, I had my brief appointment (I wanted somebody to look at a suspicious mole) and that was it. No problems, I’m fine.

Later, at the original ZocDoc appointment time, I received that promised text message reminding me of my visit and helpfully offering to give me additional support if I reply with the message ’s’.  I did, and talked with a very kind, helpful ZocDoc representative who assured me that they do everything possible to ensure that I have a good experience, blah blah blah.

This is turning into a long rant and I appreciate, dear reader, your indulgence as I get this off my chest. But it occurs to me that ZocDoc is in a business that is fundamentally so different from OpenTable, that it may be impossible to give me a good experience. Unlike OpenTable, ZocDoc’s “customers” (physicians pay them a flat monthly fee to be listed on the site) already have too many IT systems. From insurance and Medicaid reimbursement to government-mandated certification, HIPAA, and reporting requirements, their staff is probably just too busy to deal with yet another web site. Solving that “last-mile” problem with the receptionists would require much more training and hand-holding than ZocDoc can afford.

Eventually all of this will be sorted out and sometime in the future doctors will join the 20th century IT revolution just like every other industry, but it will be a long time. If you want high-tech, don’t go to the doctor: go to a restaurant.

Yup, statins make me smarter

After a fifteen day test, I’ve concluded that 20mg of simvastatin daily has a major effect on my results on Seth Robert’s Brain Reaction Time (BRT) test.

Notice the big changes on the days before and after taking the statin (the “treatment”). The two weeks before were “clean” – no fish oil, no other special vitamins, foods, travel, or other changes in daily habits – making the change even more obvious and sudden: just one day makes the difference. (The chart shows BRT measurements roughly 24 hours after treatment).

With n=33, here’s a simple T-Test to show the effect:

## Welch Two Sample t-test ## t = 7.0834, df = 28.313, p-value = 9.835e-08 ## alternative hypothesis: true difference in means is not equal to 0 ## 95 percent confidence interval: ## 15.88029 28.79244 ## sample estimates: ## mean of x mean of y ## 71.20000 48.86364

My fellow Seattle Quantified-Selfer Mark Drangsholt, who studied something similar on himself, says 2-3 weeks of treatment helped him reduce or eliminate brain fog and it appears to help me too. This is consistent with other research that shows that statins seem to benefit the brain.

Incidentally, the statin had no significant effect on my sleep (as measured with Zeo):

Sleep (n=33)	Average (hrs)	Standard Deviation	w/Statin (n=15)
total sleep (Z)	6.418	0.625	6.424 (SD=0.58)
REM	1.796	0.416	1.814 (SD=0.44)
Deep	1.039	0.198	1.006 (SD=0.13)

I’ve already demonstrated that two or three Kirkland fish oil pills taken daily give me a statistically-significant higher score, while other obvious candidates like sleep or alcohol make no difference. Seth’s app clearly is measuring something. In my next experiments, I’ll try to pin down more precisely what that is as I refine the app to make it easier and faster to use.

Fish oil makes me smarter

We all feel more “alive” on some days compared to others. Some people call it “being in the zone”, or “flow”, where you seem more responsive to the world, able to make better, faster decisions. Wouldn’t it be nice to feel that way more often, maybe even all the time?

Well, as with any attempt to improve something, the first step is to measure the effect, and then try to notice what foods or activities make it better. Unfortunately, it can be hard to tell objectively whether you have more energy than yesterday because after all, you rely on the same brain to tell you whether you feel smart or not. On days when you’re not so energetic, maybe your brain is fooling you.

The late Seth Roberts developed some simple measurement techniques that attempt to tell objectively how smart you are right now so you can compare yourself to the way you felt yesterday, or a few weeks from now, perhaps based on some new type of food you are eating. Seth and I were working on an iPhone version of this test when, tragically, he passed away, but I’ve continued to develop the software ever since and recently came upon some results that I thought were interesting.

How I measure myself

“Brain Reaction Time” (BRT) is a four-minute test that I give myself within an hour after waking up every morning. I don’t think it matters much when or where you do it, though to be as consistent as possible, I try to tie into my daily coffee-drinking ritual — a regular time and state of mind for me, before the rest of my family gets up. The BRT resembles what psychologists call a “vigilence test”, which airline pilots and others in stressful situations can take to see if they’re fit for service. But the BRT I was working on with Seth can measure things that are much more subtle, and I’ve been using it to tell how or what aspects of my life are improving my ability to focus.

Along with my BRT scores, I track another ton of variables (exercise, sleep, vitamins, food) which I enter daily in an Excel spreadsheet. I’m working to make this much more automatic using the excellent Zenobase site, but for now the important thing is just to track it however I can.

Results: Fish oil makes me smarter

I occasionally take one or two Kirkland signature brand fish pills in the morning, and of all the different things I track, I was surprised that something so simple could have such an obvious effect on my brain reaction time.

Here is the summary chart based on the past three months of testing:

The red and blue lines are the linear model, or trend lines for each variable. You can think of them like an average, the exact mid-point of all the points through time.

If you know something about statistics, we can run a simple T-test:

## 
##  Welch Two Sample t-test
## 
## data:  rik$ptile[rik$Fish.Oil == 0] and rik$ptile[rik$Fish.Oil > 0]
## t = -2.2129, df = 54.212, p-value = 0.03113
## alternative hypothesis: true difference in means is not equal to 0
## 95 percent confidence interval:
##  -15.3903411  -0.7599052
## sample estimates:
## mean of x mean of y 
##  44.10345  52.17857

In other words, we can say with 95% confidence that the effect is real. The p-value, which is almost zero, is powerful evidence that whatever is going on is not due to chance.

What else might matter?

I tried my test on several other variables. For example, here’s how my scores look on days when I’ve had a glass of red wine or beer:

Again, statistically you can see the difference when we do the T-Test:

## 
##  Welch Two Sample t-test
## 
## data:  rik$ptile[rik$Alcohol == 0] and rik$ptile[rik$Alcohol > 0]
## t = 0.3831, df = 69.495, p-value = 0.7028
## alternative hypothesis: true difference in means is not equal to 0
## 95 percent confidence interval:
##  -5.827448  8.598423
## sample estimates:
## mean of x mean of y 
##  50.22222  48.83673

The p-value is much higher – so high in fact that we can assume that alcohol really has no effect.

How about Vitamin D? Here’s the result:

## 
##  Welch Two Sample t-test
## 
## data:  rik$ptile[rik$Vitamin.D == 0] and rik$ptile[rik$Vitamin.D > 0]
## t = -1.134, df = 41.954, p-value = 0.2632
## alternative hypothesis: true difference in means is not equal to 0
## 95 percent confidence interval:
##  -11.408090   3.199757
## sample estimates:
## mean of x mean of y 
##  46.33333  50.43750

Perhaps a tiny effect, but that high p-value says it’s pretty unlikely. Since I usually (but not always) take Vitamin D on the same mornings I take fish oil, I’m pretty sure this is just an artifact of the data.

Fading Effects

How long does the fish oil effect last? I test about 24 hours after taking two pills, but will the effect remain a day or two later?

If the fish pills help, then I’d expect the improvement to fade a bit each day after I stop taking them. And that’s exactly what I get:

See how my “Fish Oil” scores decline as I get further from the day I took the pills? If the effect were truly random, you wouldn’t expect such a constant slope in the graph. It really does seem like something is going on here.

Sleep doesn’t matter

Okay, perhaps I’ve convinced you that fish oil helps improve the scores on this test. But we all know that good sleep is perhaps the single most important factor in how well we feel. Maybe the fish oil just helps ensure a good night’s rest?

Nope. I track my sleep very carefully, using a Zeo headband that can tell precisely when I fell asleep, and whether or how long I might have been awake in the middle of the night.

Surprisingly, sleep seems to make no significant difference in my test scores. Here’s a graph, with blue dots showing my scores on days when I slept less than my average, and red dots when I slept more. See any patterns? (I can’t either)

## 
##  Welch Two Sample t-test
## 
## data:  rikN$ptile[rikN$Z <= meanZ] and rikN$ptile[rikN$Z > meanZ]
## t = 0.6063, df = 80.505, p-value = 0.546
## alternative hypothesis: true difference in means is not equal to 0
## 95 percent confidence interval:
##  -4.799337  9.005546
## sample estimates:
## mean of x mean of y 
##  50.51220  48.40909

Again, the high p-value, plus the similarity between the two means is pretty good evidence that sleep has little to do with my BRT.

Conclusions

This is not the first claim that’s been made about the relationship between food and BRT. Seth Roberts noted that he scored higher after eating butter, and Alex Chernavsky showed that BRT is affected by caffeine.

I’d need a double-blind study, perhaps conducted with dozens or hundreds of individuals to “prove” these results scientifically, but that’s not the point of this test. I found something that apparently works consistently for me, and it lets me easily test many other types of variables. By looking at other outliers in my BRT results, I hope to find other foods and activities that can make me smarter too.