Found on RunnersWorld.com
Regular exercise is essential if you want to improve your fitness. But vacations, work, or family obligations can derail even the most dedicated runners. When that happens to you, don’t get discouraged by the missed workouts. Simply start up when you can, scale back your pace, and increase your walk breaks. You’ll find that it’s much easier to regain your fitness than it was to build it. Here’s how to approach those first runs, no matter how long you’ve been away.
The Break: One to two weeks
The First Day Back: Run two to three minutes per mile slower than your average pace, and run about half the distance of your previous typical run to avoid soreness. Take more walk breaks.
The Break: One month
The First Week Back: On Monday, run 15 minutes using a ratio of 15 to 30 seconds running/30 seconds walking. Tuesday: Walk 30 to 60 minutes. Wednesday: Run 15 to 20 minutes using a ratio of 15 seconds running/30 seconds walking (more seasoned runners do a 1:1 ratio). Rest Thursday. Friday: Run 20 to 25 minutes using 20 seconds running/40 seconds walking (veterans use 1:1). Saturday: Walk 30 minutes. Sunday: Run 25 to 30 minutes using a ratio of 40 seconds running/20 seconds walking (veterans use 90:30).
The Break: 60 days or more
The First Month Back: During week one, follow the plan above, but maintain a ratio of 15 seconds running/45 seconds walking. On week two, run for 30 minutes on Tuesday, Thursday, and Saturday using a ratio of 40 seconds running/20 seconds walking (veterans can use 60:30). For week three, run 30 minutes three times a week and use a ratio of 25 seconds running/35 seconds walking (veterans run 90:30). During week four, run 30 minutes three times a week and employ a 30 seconds running/30 seconds walking ratio (veterans use two minutes running/one minute walking).