This SciShow-clip discusses this study and others. https://youtu.be/HsonXuJs8-s https://youtu.be/HsonXuJs8-s I do it most mornings for (anecdotal) "waking up

This SciShow-clip discusses this study and others. https://youtu.be/HsonXuJs8-s https://youtu.be/HsonXuJs8-s I do it most mornings for (anecdotal) "waking up the mind" when I'm tired. Sometimes it feels like the world goes from SD to HD. I don't do it 90 seconds though more like 30 tops and I don't believe that I'm less sick because of it. For me it's also a psychological test of "can I chose to do something that is tangibly uncomfortable when it's super easy to just stay nice and cosy".