Overtraining does not announce itself. It builds over weeks of feeling slightly wrong — slow runs, poor sleep, a short temper — until one day you cannot run.
By Alex · 6 min read
Six weeks before my goal marathon, I could not finish a 5-kilometer easy run.
I had been training for 20 weeks. The mileage looked right. The workouts were hitting the numbers. But I felt empty — heavy legs, hard breathing at a pace I should hardly have noticed, and a complete lack of motivation that I kept explaining away as pre-race nerves.
It was not nerves. It was overtraining syndrome.
I withdrew from the race. Recovery took eight weeks. Here is what I missed.
Overtraining syndrome (OTS) is a medical condition caused by too much training without enough recovery. It is not the same as normal tiredness, which goes away after a few rest days, or short-term overreaching, which clears in 1-2 weeks of easier training.
Real OTS can take weeks or months to clear. The hormonal problems behind it — high cortisol, low testosterone, and a stress system that will not switch off — do not correct themselves overnight.
The key point: you cannot train your way out of OTS. The only treatment is rest.
Most runners who develop OTS can look back and find the signs 3-6 weeks before the crisis. On their own, the signs look small. Together, they form a clear pattern.
Performance stops improving, or gets worse. Workouts that should be manageable feel hard. Interval pace feels harder than your training log says it should. You start a tempo run at target pace and cannot hold it.
I called this "tired legs" and pushed on.
A higher resting heart rate. A resting heart rate 5-7 beats per minute above your normal level for several mornings in a row is a reliable early warning. If you wear a smartwatch, the data is already there.
I noticed it but did not track it properly.
Poor sleep. Trouble falling asleep or staying asleep, even though you are physically tired. That is the stress hormone at work: your nervous system stays switched on even when your body wants to rest.
I thought I was anxious about the race.
Mood changes. Short temper, no enthusiasm for running, and trouble concentrating. Running should improve your mood, and the runner's high is real. If your runs leave you flat or irritated, something is wrong.
I thought I was stressed about work.
Soreness that will not go away. Some soreness is normal. Soreness that does not clear between runs, and is still there three days after a workout, means you are not recovering.
I put this down to "training hard".
Overtraining is a mismatch between your training load and your ability to recover. The usual causes are:
Increasing mileage too fast. The standard guideline is no more than a 10% increase per week. Breaking that rule, especially while keeping the intensity high, overwhelms your body's ability to repair itself.
Not enough easy days. Hard sessions need genuinely easy recovery days, not "slightly less hard" days. If your easy pace is still within 15% of your threshold pace, it is not really easy.
Stress outside running. Lack of sleep, big life events and illness all reduce your ability to recover. A training load that is fine in a calm period can tip you into overtraining in a stressful one.
A taper that never happens. Some runners resist cutting their volume during the taper because it feels like falling behind. But the taper is a planned drop in load, and your body absorbs your training during that time. Skipping it often means arriving at the start line already tired.
If you catch OTS early — performance has stalled, your heart rate is up, your mood has changed a little — the plan is simple:
Full OTS is different. If you cannot run without feeling terrible, your mood is badly affected and your motivation has gone, recovery takes longer: 4-8 weeks with very little structured running, or none at all.
The best prevention is regular, structured monitoring:
Track your resting heart rate every day. Three days in a row of 5 or more beats above your normal level is your early warning. Use it.
Score every run from 1 to 5 for how hard it felt compared with how hard it should have felt. If your easy run keeps feeling like a 4 when it should feel like a 2, look into it.
Put recovery weeks in your plan. Every 3-4 weeks, cut your volume by 30-40%. Every serious training plan includes this for a reason. Use it.
Know the difference between training hard and overtraining. Training hard makes you tired, and that tiredness clears after 24-48 hours of rest. Overtraining makes you tired in a way that does not clear, however much you rest.
The aim of training is to be tired enough to adapt and rested enough to absorb those adaptations. OTS happens when you get the first half right and ignore the second half completely.
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