Missed three weeks of running due illness, 10-mile race coming up in 12 days

From experience, it's really a gamble to know how your body is going to respond. I've had flus that totally wiped out my fitness (after recovery), and other times flus that barely done anything. And it only took 2 weeks to recover lost fitness.

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In your case it seems like your illness was relatively heavy, so I would advice to take it easy. See how your body is responding after your first run. And don't rush to get back. Maybe you'll feel ok, maybe you'll feel bad.

Yeah, it's really a toss up with how your body will respond to illness. If you were out for only three weeks, you'll gain that fitness back relatively quickly (probably about two weeks to get back to 100%). However, I know after a long illness my body sometimes takes a few weeks to even a month to feel good racing again. I would take it easy for the next week or so and just see how you feel. Taking it easy is important. If the goal really is an October marathon, there is no point in rushing right now. See how you feel a week from now and then make the call about the race. Good luck

You won't be ready for a hard 10. You might be OK for the first 5K, so I would look for a race of that length. Being sick for that amount of time will deplete your strength for longer than that.

That's how I was leaning. Based on these helpful replies, and the fact that I'm still not 100%, I'm probably going to treat this as a 10-mile marathon pace run or even easier. It's the first race of the year (I'm in the midwest and itching start to outdoor races).

Did 3 miles at recovery pace on the treadmill, overall felt great. I'll see how I feel tomorrow morning. Heart rate was about 5-6BPM higher that when I did the run 3 weeks ago, literally 2 days before getting sick, but that's to be expected not having run for basically 3 weeks. I'll do 5 miles at easy pace tomorrow (assuming I don't somehow get worse) and go from there. Hoping I can at least do the race as an easy 10-mile run. It's a fun course and I miss the general vibe of races not having raced in the midwest since last November.

My 2 cents is to run it as a progression run. Take the first 5 miles fairly easy (like marathon pace +15) and then pick it up the last 5 miles and try to catch as many people as you can with your last mile being your fastest.

You'll get a good workout in, finish strong, practice your racing tactics, and end on a positive note.

If you took 3 weeks off there's no way you'll get in top shape in 12 days and if you go out too hard you'll likely crash and have to suffer for 5+ miles... What's the point of that.