Originally Posted by aaronmcd

yeah ctl is literally TSS per day. So 20 CTL literally means ~12 minutes of hard riding per day. 50 ctl means ~30 minutes of hard riding per day. (Assuming "hard riding" is around threshold effort)

So seeing the 19 CTL in April I'm of course wondering if you are new to bike riding? If so my guess is that getting up to 50 CTL after a few months isn't bad at all, but if you keep riding you will realize its not hard "physically" to ride a lot more. It doesn't hurt the shins and knees like running. I personally found riding more miles was physically easy and even fun (exploring farther and farther) but finding time or getting good training miles was the harder part.