NEW ON POLICYSPHERE: Manhattan Institute Publishes Great New Manifesto On Higher Education

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Yesterday we wrote to you about two new significant studies that show a strong link between exercise and political health outcomes, surfaced by Derek Thompson, who has a very interesting new Substack.

We thought we would expand on this by pointing to other studies that show links between an active lifestyle and good outcomes, and more specifically, between weightlifting and exposure to sunlight/vitamin D and mental health.

A 2024 systematic review and meta-analysis found that resistance training significantly improved mental health outcomes in older adults, with mean effects of -0.94 for depressive symptoms and -1.33 for anxiety symptoms.

A comprehensive review found that resistance exercise produces anxiolytic effects across a range of dependent measures, experimental procedures, and participant populations.

A meta-analysis showed strength training had large and significant effects on anxiety (SMD = −1.75) and depression (SMD = −1.61) in adolescents.

Harvard research found that people with mild to moderate depression who performed resistance training two or more days a week saw "significant" reductions in their symptoms.

Moreover, research shows weightlifting alters levels of myokines (muscle-produced signals) including brain-derived neurotrophic factor (BDNF), insulin-like growth factor 1 (IGF-1), interleukin 6 (IL-6), and irisin, which may have beneficial effects on the brain, so there is evidence of a neurobiological mechanism that would explain why lifting weights leads to better mental health.

Meanwhile, when it comes to the Sun…

Multiple studies report that vitamin D deficiency is associated with symptoms of depression and anxiety, with lower levels found in persons with schizophrenia (35.1 pg/ml) and major depression (37.3) compared to healthy controls (45.9).

A meta-analysis of 25 studies (n = 7534) found vitamin D was effective in individuals with major depressive disorder when vitamin D supplements were taken for ≥ 8 weeks.

Once again, there is evidence of a plausible neurobiological mechanism, in this case, that sunlight exposure helps produce serotonin (the so-called "happiness" hormone—antidepressants are intended to boost your serotonin) and regulates melatonin for better sleep.

What's the policy angle?

Well, we're not going to fantasize about some big program paying people to lift weights or get a suntan, as those tend to show outcomes that are mainly driven by selection bias (in other words, people who were going to exercise anyway follow the program, the rest drop out). It's also a very "social engineer" approach to human life which is unpleasant.

There are, however, two obvious policy choices which would do limited, but real, good:

First: doctors should (and guidelines should encourage doctors to) systematically prescribe or hand out vitamin D supplementation whenever they see a patient. You honestly don't need to test their blood first. If somebody works in an office, and/or it's the Fall and Winter months in a temperate or cold climate area, there's already a virtual certainty they are vitamin D deficient to at least some extent. Meanwhile, there are no negative side effects associated with overconsumption of vitamin D supplements (unless you take an absurd amount). In France, if you see a doctor for whatever reason at any time between September and May, you will leave, among other things, with a prescription for vitamin D supplements. In the US, whenever you see a doctor or interact with the healthcare system, you should be leaving with vitamin D tablets (the supplement companies will give them for free for marketing reasons).

Second: it's probably too late for policy to help the current generation, but we can maybe help the next one. Every public school in America, under pain of losing Federal funding, should adopt the so-called La Sierra High School PE Program. As detailed in the wonderful documentary The Motivation Factor (trailer), this program was a pioneering model during the Kennedy years, which enrolled high school students into one hour of rigorous calisthenics every morning. The effects were stunning, and not just on health and fitness, but also discipline and academic outcomes since, guess what, human adolescents are not meant to sit on a chair 6 hours a day. Additionally, if they live in a sunny state, they should do most of the exercises outside, and if they don't, they should get free vitamin D as well. Given the twin crises of obesity and mental health, this is a no-brainer.

Want to MAHA? Sun and steel. Sun and steel.

Policy News You Need To Know

#LadyLiberty — This is not a new proposal, but we've only seen it now, and it's very good and timely: Scott Alexander proposed that for America's 250th Anniversary, we clean up the Statue of Liberty. Its bronze originally had a shiny orange-gold color, but it turned into green due to oxydization. We would make two further amendments. First, the traditional way to prevent bronze statues from losing their color to oxidization is gold plating. Do we think the President might like gold plating? Second, while we're at it, we should remove the awful Emma Lazarus Poem and replace it with some great quote about liberty—perhaps from President Trump's historic Mount Rushmore speech?

#HigherEd — Chris Rufo and the Manhattan Institute have published an impressive "Statement on Higher Education."

OUR ANALYSIS HERE.

#HigherEd — Speaking of, Claremont McKenna has a new study (PDF) out measuring how faculty teach contentious issues across millions(!) of syllabi; in this case, Israel-Palestine, policing, and abortion. The results will not shock you. Professors systematically present only one side of these debates rather than exposing students to the full range of scholarly perspectives. The study reveals what the authors call a "strong asymmetry," where influential works supporting certain viewpoints are widely assigned, while their academic critics are largely ignored. For example, on criminal justice, Michelle Alexander's The New Jim Crow appears in over 5,000 courses but is paired with its most prominent critic (James Forman Jr.'s rebuttal) only 3.5% of the time. And so it goes.

#MAHA #Vaccines — New study: across a period of 24 years, in a sample of 1.2 million kids, cumulative aluminum exposure from vaccines had no significant, positive relationships with any chronic disease. There's no association, let alone any causal link. Looks like, for all his good intentions, RFK, Jr. is wrong about this too. (Via Crémieux)

#Ed #DOGE — Yesterday, the Supreme Court ruled in a 6-3 decision to lift a lower court injunction that had blocked the Trump administration's plans to dramatically reduce the workforce at Ed. The Supreme Court's decision was unsigned, and the majority did not explain its thinking; it's not a final victory, and the case will continue to work its way through the lower courts. Two things with broader implications seem to be indicated by this, however: first, the Supreme Court's patience with judges issuing nationwide injunctions or equivalently paralyzing judgements is wearing thinner and thinner; second, the Supreme Court takes a benign view of the Executive running the Executive Branch as it wants.

#Immigration — Iran has just deported 1.1 million illegal aliens over the past year, and in the middle of fighting a war with Israel and the US no less, reports the Times of London. It is very plainly true that, unlike some assertions you sometimes read, mass deportations are perfectly possible logistically.

#Immigration — Speaking of what's possible, check out this headline: "ICE arrests more than double throughout the country, including California"

#AmericanManufacturing #Politics — Well, it's the oldest trick in the book, but still, noteworthy reminder from the Journal: "The White House says nearly $2 trillion in manufacturing-related projects announced this year are due to Trump’s commitment to revitalizing American industry. A WSJ analysis found some projects were in the works before Trump took office, or involve typical company spending on things like R&D and equipment"

#Kids #MentalHealth — Degrowth ideology and environmental doomerism are bad for lots of reasons. A particularly important and poignant one: its impact on kids' mental health. Kids are most exposed to the harmful effects of these ideologies, since they're a narrative about what the world will be like when they grow up. As Chelsea Follett writes in Human Progress, there is mounting evidence that these narratives contribute to the mental health crisis among kids and teens.

#Life — If you followed the latest shenanigans in the ongoing controversy over nationwide injunctions, the Supreme Court banned nationwide injunctions, except for a few exceptions, including class actions. Predictably, lower court judges have been using this loophole, in particular a District Judge stopped implementation of President Trump's executive order on birthright citizenship on the obviously-farcical basis that "future persons" to be born on US soil are a "class" and can therefore be protected by a nationwide injunction. As many commenters have pointed out, pro-life groups should start spamming the judiciary with requests for injunctions on the basis that "future persons" are now a protected class.

#DOGE — Last week, the State Department carried out a reduction of 2% of its personnel.