OP post count does not always equal right answers. Unlike some I did not take the winter off, Rule 9! Not that my results are of any significance and by your posts you represent yourself as much younger and in better physical condition than myself however I'll share what has worked for me. You want speed first you have to put in the time in the saddle. As others have already mentioned that alone will get you faster to a point. Add in some structured workouts where you focus on speed and speed plus duration and you will exceed where you would be simply by putting in the miles. Rest is important, but rest does not have to equal total lack of activity. Some folks simply do not know "how to train properly." So the answer could be a yes and a yes but it really depends on where the asker is starting from.

And hammering to me is anything beyond 80% effort; listen to your body and you'll know what that means to you without the expense of HRM and other electronics. Cycling is really not all that different from running IMHO and if you look at the changes to the mile record since Bannister broke 4:00 in 1954 the record changed 16 times until into the 80's. Twice in the 90's. HRM are pretty common today and yet they do not seem to help runners train any better. For what it is worth I broke 5:00 min in 9th grade and improved each year until my peak 11th grade with a time of 4:36, still a School JV record. I think it is fair to say I have a bit of understanding of training principals. Ride more, ride hard, HTFU and it does not get easier you just go faster are words to live by. If it gets easier you are slacking and you need to meditate on Rule 5! Word!