The numbers are hard to read at low light on a 520.
You can try and use the Remote Monitor/Player on a larger screen, when doing the workouts indoors.
Thank you Armando. Unfortunately, my workouts are entirely outdoors. Early morning, around dawn, the XWP screen is rather difficult to see. Once the sun comes up, it’s fine. The normal garmin workout screen uses a combination of larger fonts, reversing the color scheme at night, etc, which does really well at cutting thru low light conditions.
same here… 56+ years old, it is not easy to read my Garmin 820. I ride in a track with reading glasses 
Same here. I made this same request about 6mos ago. I’ve since stopped using the workout player and create a Garmin connect workout but emulate the mpa targets by using he Garmin conneciq fields…I watch them and when I get to the target mpa I press the lap button to start my next interval. Really annoying to create the workout but at least I can see the numbers.
If you’re working out using MPA, you could also try the TTE app and configure it with your MPA targets. This could be put in larger font on the 520/820.
Thx. I tried to do that first but didn’t understand how to calculate the mpa percentage into tte.
If your Target MPA is 50% of PP Reserve, for example, set the value in the app to TP + (PP - TP)*0.5.
Thx. I’ll try it!