Tapering, which is a reduction in your marathon training, enables you to recover from the training you’ve completed so that you’re fresh and ready to go on race day. Follow these tapering guidelines before your marathon:
Reduce your running volume but maintain the intensity with tempo runs and interval workouts.
Don’t try any new workouts.
Increase how much carbohydrate you eat to at least 70 percent of your calories over the final week before your marathon.
Stay hydrated by drinking enough water and sports drinks that your urine is a pale yellow color.
For a 3-week taper, reduce your peak weekly mileage by
30 percent the first week
50 percent the second week
65 percent the week of the marathon (not counting the marathon itself)