Both. There's an effect from large bodies of water, streams, even pools. Then there's an effect from salt water.
There's even an effect from being in green spaces like forests in summer that has an effect on pain tolerance. You can buy a specific wavelength green light, 525nm, that can help with pain. I have one, and honestly if it's placebo then I'll take it, I'm not proud lol. It's called an "Allay" lamp. https://allaylamp.com/ (I'm not affiliated with them, just a customer)
Green light study: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5242385/
Wasn't some of that money lent by saudi princes? A group of people who tend to take revenge against those who wrong them.