Sub 5 minute mile in 30 days

If you can run 52/53, you can probably run 2:15 for 800 at worst and proabably a 5:30 mile right now unless you are in horrible shape, i.e. sitting on the couch, doing no jogging.

Run 4-5 miles, 5-6 days a week, even every day. Go at a steady pace. Take a day off when you get tired. Once or twice do some intervals. Do 200's with a few minutes rest in between. Do 6-10 of them. The next time do 400's. Do 6-8 400's. Don't rest more than 3 minutes for your 400's and 2 minutes for your 200.

Not gonna happen in your short time frame, and probably not gonna happen ever, given your long term laziness.

Everything Greg said, basically. Maybe do 3-4x800m too with ~4 minutes between sets; since you said you have more of a sprint background, you might need to focus on endurance more than speed.

You don't need super high mileage for a 1600m. I don't know what your mileage is right now or how many days per week you run, but I would guess that somewhere around 20mpw would be enough. The main thing is don't increase your mileage too much or too quickly because you'll get hurt.

In terms of long runs, 5-7 miles (or 40-60 minutes if you measure runs by time) should be enough (it would be better to start with a shorter long run and build up as you like). What you could do is run most of it at a normal pace and then tempo the last 5-10 minutes; this helps you get used to running faster even after you've been going for a while.

Also, if you're trying to improve your time significantly in a short time frame, you have to be really careful with recovery so you don't get hurt. Make sure you warm up and cool down properly and stretch/foam roll after runs. Strength training and mobility drills are also helpful.

Good luck!

exciting goals!!!!! I have coached runners for 30 years and have some free resources (dale.magnin@gmail.com) . I am 67 and still train a bit seriously. I run three long runs a week. I ran 56 marathons and won one. Enough about me!. The 49 second screams that you are ready. I can remember when I was 20 and went to show off for a coed and ran 6min. I was very disappointed. But by the time I was 30 I was a chunk under 5. Even when I was 40 4:50 4 times was a easy "do". I can help you if you want ,but I would start with maybe 3 runs a week 3,4,5, miles or whatever feels fun at this point. More if you want!

If you can run 53 today, you can run 5 minutes in 30 days. Run every other day for 30 minutes the first week at 7:30 per mile. Run 35 minutes the second week except one day pick up the middle 2 miles to 7 minute pace. Run 5 days per week the next 2 weeks for 35 minutes for 3 days. One day do 6x400 at 75 seconds with as much rest as required to maintain pace. The other day pick up the middle 2 miles to 6:30 pace. That's it.