I spent many years as a young man with the metronome cranked up to 152 BPM playing 4 notes per click. I was the fastest guy on the block, but my playing really wasn't that good - it was just fast. AND my arms, hands, and fingers were tense.
Fast forward a few decades, and speed is no longer the prime objective. Playing tasty is what I'm going after these days. Yet, I do want to be able to put the pedal down and pass a few cars when I need to - and its nice to have the horse power under the hood when needed.
So I discovered something a few years ago that I wish I'd know when I was a teenage speed freak. The slower and more relaxed you are when you practice, the faster you can play.
For example, if you are playing along with a metronome set to 120BPM, try slowing it down to 80 BPM or even 75 BPM. It will feel like you are playing in slow motion. But try it for 60 minutes. Make sure you hands - and entire body - are TOTALLY relaxed! (This is important). Use minimal downward pressure on your fretting hand - let it GLIDE over the notes you are playing.
After an hour, turn that metronome back up to 120 BPM and see how EASY it is to play fast - how relaxed your hands feel. If you do this once, you will be hooked.