Newsletter #191 - Goodbye 2021, Hello 2022 🥂
Welcome to the New Year’s Day edition of the humanOS newsletter!
Hope y’all are still enjoying a safe and relaxing holiday. For this week, I thought it might be fun and useful to look back at some of the most interesting research of 2021 (well, at least, of the findings that we had shared). So, I decided to comb through the past 52 newsletters of this past year, and revisit the five studies that I thought were the most compelling.
Incidentally, it was very hard to narrow it down to just five. Like… I almost gave up on the exercise entirely because it was so difficult to choose! In the end, I wound up picking the items that weren’t necessarily the most important, but that seemed to be most actionable at the individual level - meaning things that you might be able to take advantage of for yourself. Hope y’all enjoy!
Research Highlights of 2021
💪🏼 Sleep deprivation may interfere with muscle rebuilding.
Healthy young adults were subjected to one night of normal sleep (control) and one night of total sleep deprivation in a randomized crossover design (meaning that all participants were eventually exposed to both conditions over the course of the study). When the subjects were deprived of sleep, muscle protein synthesis (the process of building muscle mass at the cellular level) was reduced by 18%. When the researchers examined the participants’ bloodwork, they found two major clues as to why this was the case. First, plasma testosterone area under the curve (AUC) decreased on average by 24% in the sleep deprived condition, especially in males - all male subjects showed lower testosterone levels when they lost sleep. Testosterone, obviously, plays a key role in the promotion of muscle protein synthesis. Secondly, cortisol levels were 21% higher during sleep deprivation, compared to control. Cortisol, in contrast to testosterone, actually drives muscle breakdown. This lines up with prior research suggesting that inadequate promotes loss of muscle mass, and suggests that this may be mediated by a catabolic hormonal environment.
💊 Glucosamine supplementation is associated with lower all-cause and cardiovascular mortality.
Researchers combined data on dietary intake and supplement use from National Health and Nutrition Examination Survey (NHANES) participants (n=16686) with mortality figures from 2015. After adjusting for an array of potential confouding factors - such as age, sex, education, smoking, and physical activity - they found that respondents who took glucosamine/chondroitin for at least a year had a 27% reduced risk of all-cause mortality, and a 58% reduction in cardiovascular mortality specifically. This lines up with previous studies, including one in the UK which found a 15% reduced risk of cardiovascular events in glucosamine users, and an analysis in Washington state that found a 20% reduction in all-cause mortality associated with glucosamine use. To learn more about potential underlying mechanisms, check out our past interview with Michael Ristow.
🧘 Stretching is surprisingly effective for lowering blood pressure.
Researchers randomly assigned 40 older adults to two groups: one group performed a whole-body stretching routine for 30 minutes a day, five days a week. The other group walked briskly, for the same amount of time and frequency. All participants had elevated blood pressure, or stage 1 hypertension (systolic pressure 130-139 mmHg or a diastolic pressure of 80-89 mmHg). Both interventions resulted in blood pressure reductions, but the stretching was more effective. Why though? When a muscle is stretched, blood vessels are also stretched. This appears to induce structural changes within blood vessels that can decrease arterial stiffness. Animal models have also shown that stretching blood vessels may trigger the release of metabolites from the cells lining the blood vessels, which can cause the blood vessels to dilate. Any of these mechanisms would reduce resistance to blood flow, which in turn would reduce blood pressure.
🤧 Antihistamines may reduce the benefits of exercise.
Recent research suggests that histamine may mediate various important physiological responses to exercise. This raises the question of whether suppressing histamine production with medication might have an impact on training adaptations. To explore this question, researchers from Ghent University and the University of Copenhagen performed two experiments. In the first, they had eight participants ride an exercise bike for 40 minutes without antihistamines, then do the same exercise after taking two over-the-counter antihistamines. Typically after exercising, blood flow to muscles is dramatically boosted, but this effect was significantly dampened when participants took antihistamines. Next, the researchers had 18 men embark on a training program on the bikes, exercising three times per week for six weeks. Participants were randomly assigned to take either placebo or the aforementioned antihistamines. Those who had been taking antihistamines showed less improvement in exercise efficiency, blood flow, and muscle growth, compared to placebo. Insulin sensitivity and response to an oral glucose tolerance test significantly improved for controls, but did not at all in the antihistamine group. Why? One of the roles of histamine in the body is to regulate blood flow in muscles, and boosted blood flow is crucial for repairing and building muscles.
Important note: the antihistamine dosing in this study was quite high (540 mg of fexofenadine/Allegra + 300 mg of ranitidine/Zantac or 40 mg of famotidine/Pepcid), and blocked both H1 and H2 receptors. So don’t panic yet.
😴 Exposure to blue light before bedtime results in poorer sleep quality.
Researchers in Japan exposed 11 healthy young men to three conditions for one hour before bedtime: 1) incandescent light, 2) blue-light, or 3) blue light but with blue light-blocking glasses on. There was not a significant difference in total sleep time between the conditions, but exposure to blue light resulted in a significant decrease in the ratio of deep sleep (47 minutes, 18.4% of sleep), compared to both incandescent light (61 minutes, 26% of sleep) and to blue light while wearing blue-blocking glasses (69 minutes, 29.3% of sleep). Getting adequate deep sleep has been shown to be particularly important for memory and cognition - if you want to learn more about how to achieve greater amounts of deep sleep, check out our interview with Kristine Wilckens.
Random Trivia & Weird News
🍾 The longest recorded flight of a champagne cork was 177 ft 9in (54.18m).
That’s more than half the length of a football field!
Although the physical properties of champagne suggest that perhaps a launch of that distance shouldn't be so surprising. When French researchers took a closer look at what exactly happens when a champagne bottle is uncorked, using high-speed video imaging, they found that gases burst out at speeds similar to the exhaust of a fighter jet.
Videos We Loved This Week
- Adam Grant: How to stop languishing and find flow. Via TED.
- Tristan Harris: How better tech could protect us from distraction. Via TED.
- Jason Fried: Why work doesn’t happen at work. Via TED.
The humanOS Bookshelf
Atomic Habits by James Clear
I know I have plugged this book before, but I always find myself recommending this book around this time of year, because it’s just that good. At the start of the new year, many of us are evaluating the past patterns of our lives and resolving to start anew. But our efforts are usually pretty short-lived, because we fail to develop an effective system to assess our current habits, reinforce good habits, and abolish bad habits. In this book, James draws upon a wide array of evidence from psychology, biology, and cognitive neuroscience to construct a guide to doing just that.
So what do we mean by habits? James defines habits as behaviors that are repeated enough times to be nearly automatic, and not demanding cognitive effort or willpower. Like brushing your teeth, or heading to the gym at 5:00 pm every day, or making a green smoothie every day for breakfast. These automatic processes, which are mostly mundane things that we take for granted, are actually foundational to all of our goals.
The problem, of course, is that we generally don’t see the immediate payoff for any of these behaviors. You don’t drop twenty pounds just switching from regular to diet soda in a single day. It is only after you’ve committed to these behaviors for a while - after your efforts have compounded, as James puts it - that we start to see the difference.
If you wanna learn more, check out our past interview with James Clear (one of my all-time favorites), and definitely give the book a shot if you would like to jump-start those New Year’s resolutions.
humanOS Catalog Feature of the Week
Daily Performance - Introduction
Since we are talking about change and self-improvement, we’d like to highlight our Daily Performance course. This course, and indeed the entire program, is oriented around one question: Can you increase your cognitive performance and productivity by making relatively simple adjustments to how you approach your day and night? Of course, the answer to that question is an emphatic yes.
In this course, we address some of the unique challenges associated with modern work, like digital distractions. For instance, did you know that research shows that it takes on average almost a half hour to return to something that you were working on after being distracted, even if the distractor was something that only took like a minute of your time, like an email or text message? 🤦 That kind of thing consumes a ton of our time and mental energy, and in turn may lead to more stress, which takes an insidious toll on your long-term health. We also lay out how critical daily environmental and lifestyle inputs affect various dimensions of cognition - probably more than you realize. Fortunately, all of these are modifiable, at least to some extent. To learn more, check out the course, and the entire Daily Performance Program.
Happy New Year, and we'll see y'all next week!