Hopefully by day three you are past the 85-percent threshold, so on that day you can go for an easy aerobic run, but cut the distance short by 1 to 2 miles or 10 to 15 minutes. So if your normal easy run is 6 miles, then just run 4 to 5 miles, and see how you feel. The next morning you need to take inventory again. If you feel close to 100 percent, then do your normal easy day—full mileage this time. And the following day, you'll likely be ready for either a conservative workout or a long run that is a couple of miles shorter than normal.
Don't Be Deceived by the Post-Run "High"
One of the interesting aspects of running when you are coming back from a cold is that you'll probably feel the best in the hour or two following the run. But this is a problem because you can easily convince yourself that you're now 100 percent healthy, and that you can get back on your training schedule. Wrong. You need to wait until the next morning to take inventory of how you're feeling. Hopefully you're feeling better, but my guess is you won't be feeling as good as you did in that first hour or two after the run. So be mindful of this phenomenon when you're figuring out when to run your next workout.
Use a Pencil or Hire a Coach
My college track coach liked to say that you should write your training plan in pencil. His point was that the plan that you write out will almost never work out exactly as it's laid out on paper, yet if the plan is written in pencil, then you don't feel bad when you have to change it.
My biggest problem with online training schedules, free or paid for, is that it's hard not to head out the door when the training calendar has a workout on it and you've got a cold. Most people ignore how they're feeling, and try to do the workout because that's what the training schedule says. The workout goes poorly and now not only are they sicker than when they started the workout (they've stressed their immune system, which is already working hard to fight the cold) but they're also disappointed about their workout. So what do they do? Head out the next day on the run that's assigned on the training calendar ? and just delay getting better by another day. It's a vicious cycle.
It's at this point where a coach can really help. Ninety percent of what I do with the people I coach is prevent them from making bad decisions. They're all motivated and are serious about their running, so they don't need a cheerleader to get them out the door. But none of them want to take days off, or run a couple of easy days when they're sick (same goes with little injuries or life stresses). Think of a coach as a guide who helps you miss fewer workout days throughout the year. People without coaches tend to get injured and sick more often, and when you look at their year, they miss more days of running than those with a coach.
So if you're serious about your running, or if you've struggled with injuries and sickness during your training, consider some personal coaching. Get an objective person on your side; it will lead to more consistent training, which eventually lead to faster racing.race.