Overtraining does not have a single cause, but rather, results from a constellation of factors. It also does not happen overnight. You don’t go from being fine to being overtrained in a week. It requires a prolonged period of imbalance. Here’s what to look for:
Diminished acute performance
It’s not just a background feeling of being tired and unable to recover. You’re workouts are a mess. You’re not hitting your targets for intervals and you’re quitting intervals early. You feel sluggish and heavy, and it takes longer to recover hard efforts.
The relationship between workload and recovery is dysfunctional and your acute workout performance is diminished, so the conditions for positive training adaptations no longer exist. You’re in quicksand. You’re working hard, but the longer you continue to struggle the deeper you sink.
Erratic waking heart rate
Tracking morning heart rate, bodyweight, and mood is a common way to look for signs of overtraining. Occasional changes that go away within one or two days are pretty normal, but significant changes in any of them, and particularly two or more, over at least a 5-day period are cause for further investigation. For waking heart rate, look for a +/- 7-10 beats per minute change from baseline.
Low Heart Rate Variability
Heart rate variability is another measure we use to see how an athlete is handling their training load. Using a heart rate monitor with the appropriate features, HRV measures the variability in the times between heartbeats. Higher variability is a sign your autonomic nervous system is reacting to changes in stimuli quickly, which is what you want. Lower variability is a sign your nervous system is fatigued and not responding to stimuli as well as it could. If you plan on using HRV, it is important to measure HRV consistently and immediately upon waking, as you need a baseline level to compare against. For more information, here’s an in-depth article on HRV from Corrine Malcolm.
Some people cry more than usual, others snap at their spouses and coworkers, but increased emotional volatility can be a sign of overtraining. It’s a matter of amplitude, not the specific emotion. Your emotional responses are disproportionate for the situation, particularly compared to how you normally respond.
Reduced sex drive
It seems pretty logical that you’d be less interested in sex when you’re exhausted, and research has shown that increased training intensity and duration can have a negative affect on libido – for men and women. Some of this may be due to hormonal changes, including the increase in stress hormone cortisol.
High perceived exertion
Not only will your power outputs be lower, but you’ll also feel like it’s more difficult than normal to produce those diminished results. This can be a sign of acute fatigue that’s perfectly normal during a training program. You’ll often see it the day after a particularly hard workout, or at the end of training blocks. The key difference is that it normally goes back to normal within a few days, or even a single day. When the mismatch between performance and perceived exertion is prolonged, it’s a cause for concern.
Along with higher-than-normal perceived exertion, heart rate is often less responsive to changes in intensity level during workouts. It takes longer and feels like it requires more effort for an athlete to get heart rate to rise. Following an interval or hard effort, it also takes longer for the athletes heart rate to come back down.
You may be overtrained when you get to the point where every day it’s a struggle to get out the door for a ride, you find more excuses to delay or skip rides, you’re bored with training, and you just don’t want to do it anymore. Again, this can happen every once in a while during normal training, but prolonged feelings of lethargy and low motivation are indicative of a problem.
While you would think that a big mismatch between workload and rest would make it easy to sleep, the opposite is often true. Overtraining can lead to insomnia, disrupted sleep, or just less restful sleep. New sleep tracking apps can be helpful for monitoring your sleep behaviors, like how often you stir and how long you stay in different levels of sleep.
Your immune system and your body are taking too much of a beating and not getting enough time or support to recover. An athlete who is overtrained may experience frequent illnesses and illnesses that take longer than normal to go away. You may also be more susceptible to both overuse and acute injuries and are more likely to start getting a series of nagging injuries.