For general tenseness, stretching helps. For about a month in January, I started stretching for the first time in way too long. My muscles were super tight, and I did notice a difference. But after a month I started having other pain as a result of the stretching. Which was kind of frustrating.
If you’re referring to the reactive tension that happens when I get anxious or intent on something, physical activity doesn’t really help. It’s more a very deliberate, conscious effort, sometimes even saying out loud to myself, “relax” because relaxing those muscles is not a natural act. It takes concentration and intention.
Thanks for asking!