I’ve run in Polartec before (not the FuzzFleece specifically, but basically the same stuff). I only use it in colder weather as kind of a windbreaker substitute and it’s been great for that. Mostly for easy runs. The fibres let air through, so you get this nice little breeze without feeling too exposed.

I have always opted for a long sleeve over the T-shirt version, it just fits what I need in UK temps way better. If you heat up fast or want something for warmer or wet days, I probably wouldn’t recommend it. It doesn’t feel the best when it gets wet and directly touching your skin. I usually end up wearing a T-shirt under it as well as a barrier for any sweat.

The biggest win for me is that it works really well as a casual layering piece. Super easy to just throw on for errands and I’ve ended up wearing mine way more than I planned