Two more things to think about while working out at work.
1.) Don't forget to network with the others that may also be using the gym. If you are in a company facility, the person you are running next to may be a key partner down the road. I have strengthened several relationships just by a few minutes of chatting before, during or after a workout. If you are in a public gym, the person next to you could be a future, client, partner or vendor (or employer!). Remember the MT rules about networking.
2.) I run a lot with motivational music, but often I will catch up on an audio book or business oriented podcast. I feel like I have double-used the time when I do that because I can focus on the material without distraction while work on my health.
Exercising to podcasts for the win!
I do all my exercising to various podcasts (including MT, amongst other things). I had to get a pair of Yurbuds (a product that does exactly what it says on the tin) so I don't need to spend most of my time putting my earbuds back in, but now I'm on the rowing machine, bushwalking, or lifting weights, always listening to something. Like you, I feel like I'm getting double duty from each minute, which tickles my desire for efficiency, and since there's really nothing else to focus on, I can really concentrate on what's being said, so it's very effective listening time. I've even found myself wanting to exercise more often when I've got a bit of a podcast backlog (or I'm halfway through listening to something particularly interesting). Given the shape I'm in, anything that gets me exercising more often is something extra valuable.