You’re deep into an intense training block, and you just feel SO tired. The legs feel heavy on the runs, your paces have gotten a little slower, and you sometimes cut your workouts short. Are you pushing yourself too hard? Or do you just need to hang on a little longer to make it to race day?

During any solid training cycle, you will feel fatigued as the training piles up. Cumulative fatigue is when the body accumulates stress from an increase in training load. This is necessary to stimulate a training response and for adaptations to occur. However, when fatigue levels reach a point where the body can’t sufficiently recover, it starts to become counterproductive. So how do you know when it’s too much for your body to handle?

Some fatigue is intentional, so we don’t want to completely pull back and eliminate any fatigue. There is the good fatigue, where it’s enough that our body can recover and adapt from, and bad fatigue, where the training load outpaces our body’s ability to recover from. What does “good” fatigue and “bad” fatigue feel like? Here are some guidelines about whether the fatigue is good or bad.

Good Fatigue:

• Tired legs on a recovery run the day after a hard workout
• Slight but noticeable increase in general fatigue following a heavy training block
• Needing to cut a workout short occasionally, but can still complete the easy mileage without difficulty
• Tired legs / slightly slower at the start of a run or workout, but able to eventually settle into a groove and progress the pace throughout the session
• Energy for day-to-day tasks is minimally affected

Bad Fatigue:

• Needing to cut short multiple workouts in a given training period. Consistently unable to hit training paces that were once manageable.
• Falling asleep during the day / always feeling tired
• Trouble concentrating or performing daily tasks
• Difficulty completing easy runs
• Decline in paces throughout a period of a few weeks
• Difficulty sleeping at night / disrupted sleep patterns
• Fatigue worsens after easy/recovery runs instead of improves

When fatigue is still in the “good” zone, your body usually can handle this amount. Pay attention to recovery during a heavy training block, and make sure you run your easy runs by effort rather than a strict pace. You can continue with your training, just pay attention that the fatigue does not become too much.

 But what should you do if the fatigue has crossed over into “bad” fatigue?  If your body is unable to keep up with the demands of training, you will need to adjust your training and recovery immediately to avoid overtraining syndrome. Here are a few things you can do to help your body bounce back after too much cumulative fatigue:

• Lower training volume to a level you can manage (reduce volume 25-30%)
• Prioritize recovery (enough sleep, proper nutrition, stretching routine)
• Go by feel for runs – use effort as your guide rather than a pace
• Re-assess after 1-2 weeks

Often, one or two weeks of reduced volume and intensity is enough to allow your body to recover fully from the fatigue it was carrying. You will feel your energy levels return, your runs will feel easier, and you have more “pep” in your step. You can return to your previous training levels, but keep an eye on any returning fatigue.

If, after 1-2 weeks of reduced training, you still don’t feel recovered, you may still have some lingering over training effects. At this point, you need to continue to keep your training reduced, and you may need to modify your original training plan and race goals. It may also be a good idea to seek out your doctor to check your bloodwork and other health baselines. 

While cumulative fatigue is a part of the training process, staying on top of the levels that your body can handle will help you continue to train consistently and keep improving. We usually recommend our athletes take a down week every 3 to 5 weeks as part of their regular training. This gives the body a chance to absorb training, recover from fatigue, and continue their progress. Read more about structuring down weeks in training at The Art of the Down Week.