Mountains or the sea?

Which type of holiday is more likely to boost Energy and serotonin levels after a long and gloomy winter? I feel emotionally drained and weak.

Sea can boost my energy and it has been proven

I find the sea really good. Expecially when there are big waves crashing into the coast.
Walking along a cliff top walk looking out on the sea is very calming. It gives great perspective.

I prefer the mountains? But I would think nothing like the seaside, for sunshine and a feeling of fresh energy.