our new @TheLancetPsych paper was the biggest ever study of exercise and mental health. it caused quite a stir! here's my guided tour of the paper, highlighting some of our excitements and apprehensions along the way [thread] 1/n thelancet.com/journals/lanps… 
the punchline was clear: amongst over 1.2M people in the USA between 2011-2015, people who exercised had about 40% better mental health than people who didn't exercise, even after we controlled for a whole bunch of things including BMI, physical health, and sociodemographics
those 1.2M people did a lot of different kinds of exercises though! this gave us a unique opportunity to really zoom in on this relationship — does the kind of exercise matter? how long were people exercising for? answering these kinds of questions needs a lot of people!
it looks like those differences mattered. for example, people who exercised for about 45 minutes seemed to have better mental health than people who exercised for less than 30, or more than 60 minutes. — a sweet spot for mental health, perhaps?
something similar was happening with the # of times people exercised. People who exercised 3-5x a week seemed to be feeling better than people who were outside that zone. Understanding these non-linear, U-shaped relationships might help us design better clinical trials one day!
the type of exercise people did seems important too! People doing team sports or cycling had much better mental health than other sports. But even just walking or doing household chores was better than nothing!
for sure — these findings are exciting, and it has been overwhelming to see the whole world talking openly and optimistically about mental health, and how we can help people feel better. It isn't all plain sailing though...
#1 — what did we even mean by "better mental health"??? there's no way you can have real doctors evaluating 1.2 million people and giving us an accurate measure of people's mental health. In this study, people were just asked how they were feeling.
(1b- this might not be the end of the world. In general, most people have a reasonable understanding of their feelings, and in depressed or anxious patients self-report evaluations are highly correlated with clinician-rated evaluations. But we could be more precise in the future)
#2 — we don't know that exercising actually improves your mental health from these data!! all we know is that people who exercised had better mental health. We tried to be very clear about this!
There's lots of reason to believe the relationship goes both ways.
But there have also been lots of studies showing that exercise does causally improve mental health, especially depression. Madhukar Trivedi's group @UTSWNews showed that people who exercise and take antidepressants do better than people who just took the meds
Why are we so excited about these findings then? One reason is because these effects could be really big! The difference in mental health between exercising and not exercising was much much bigger than things like being obese vs healthy, or being wealthy (>$50k) vs poor (<$15k)
The benefits might also be pretty accessible. Just regular walking for 30-60 minutes might help. The differences existed no matter your age, race, gender, income, education level; depressed or not depressed
Where do we go from here? Over @spring_health - our mental health startup in New York City - we're using these findings to develop personalized exercise plans. We want to help every individual feel better—faster, and understand exactly what each patient needs the most.
Just like we did with our antidepressant treatment algorithms, we want to develop quick online assessments to figure out an exercise plan that is best suited to help your mental health springhealth.com
Thats all for now! Thanks for tuning in 💕. There's so much more we need to do to reduce the global burden of mental illness, & we're so grateful for the support we've received from all over the world. altmetric.com/details/462883…
PS - for a more clinical/technical viewpoint, check out our @TheLancet podcast with Niall Boyce, Editor of @TheLancetPsych for free thelancet.com/pb-assets/Lanc… . as always, please email me for a free copy of the paper!!
