Signs You Are Overtraining (and What to Do About It)

What is the difference between overreaching and overtraining?

Sports scientists see this as a sliding scale rather than one condition. A joint consensus statement from the European College of Sport Science and the American College of Sports Medicine describes three stages. ¹

• Functional overreaching. A short dip in performance after a hard block of training. Performance comes back within several days to a few weeks and is often better than before. This is a normal part of getting fitter.
• Non-functional overreaching. Training and recovery have been out of balance for longer. Performance stays down, and recovery can take weeks or months.
• Overtraining syndrome. A longer-lasting problem that affects hormones, the nervous system and mood as well as performance. Recovery may take months, and sometimes longer.

The tricky part is that the last two look almost identical. The consensus notes that no single blood test, hormone or questionnaire can confirm overtraining syndrome, and it is often only clear in hindsight. ¹

What are the signs you are overtraining?

No single symptom proves it. What matters is a pattern that lasts, even after a few easier days.

Your performance keeps dropping

A decline in sport-specific performance is described as a hallmark feature of overtraining syndrome. ¹ You may find you cannot hold paces or weights that used to feel manageable, or you cannot finish hard sessions.

You feel tired all the time

Ordinary tiredness after a big week should lift with rest. Fatigue that hangs around for weeks, even on easy days, is a warning sign. ¹

Your sleep is disrupted

Sleep problems are part of the consensus checklist for assessing overtraining. ¹ You might struggle to fall asleep, wake often, or wake up unrefreshed despite enough time in bed.

Your mood changes

Falling motivation and rising fatigue are common in the earlier stages. In overtraining syndrome, low mood and depression-like symptoms tend to rise the most. ¹ Irritability or losing enjoyment in training you used to love is worth noticing.

You keep getting ill

Upper respiratory infections, such as colds and sore throats, are commonly reported by overtrained athletes, and overtraining may increase the risk. ¹

Niggles and injuries pile up

Low energy intake relative to training is linked to a higher risk of injury, including bone stress injuries. ² If small aches keep turning into time off, look at your load and fuelling as well as the injury itself.

Can resting heart rate or HRV tell you if you are overtrained?

They can help, but they are not reliable on their own. The consensus statement notes that changes in resting heart rate are not consistently found in overtraining syndrome. ¹

Heart rate variability (HRV) is a measure of the small changes in time between heartbeats, which reflects how your nervous system is coping. A meta-analysis found that resting HRV was largely unchanged in overreached athletes, and that some post-exercise heart rate measures rose both in athletes who were adapting well and in those who were overreached. ³ The authors concluded these measures cannot separate good adaptation from bad by themselves.

The practical takeaway is to look at trends over weeks, not single readings, and to combine them with how you feel, how you sleep and how you are performing. A wearable that tracks sleep, resting heart rate and HRV makes those trends easier to spot.

How is overtraining linked to under-eating?

Sometimes what looks like overtraining is actually not eating enough. The 2023 International Olympic Committee consensus statement describes Relative Energy Deficiency in Sport, often shortened to RED-S or REDs. ² It happens when you take in too little energy to cover both training and the body's basic needs, which is called low energy availability.

REDs can affect hormones, bones, immunity, metabolism, mood and performance, and it affects men as well as women. ² Its symptoms overlap heavily with overtraining. The IOC authors note that low energy availability should be ruled out before overtraining syndrome is diagnosed. ²

Signs that fuelling may be part of the problem can include:

• Weight loss you did not intend
• Missed or irregular periods
• Low sex drive
• Frequent bone stress injuries
• Restricting food or feeling anxious about eating

What should you do if you think you are overtraining?

The consensus is clear that rest and very light training are the only effective treatments once overtraining has set in. ¹ The earlier you act, the quicker you tend to recover.

• Cut your training back. Drop intensity first, then volume. Take at least one full rest day a week. ¹
• Prioritise sleep. Aim for enough sleep to feel alert during the day. ¹
• Eat enough. Make sure total energy, carbohydrate, protein and fluids match your training. ^{1 2}
• Keep a training log. Record your sessions, how hard they felt, your sleep and your mood, so you can see patterns. ¹
• Avoid monotony. Vary your sessions and build in easier weeks. ¹
• Count life stress. Work pressure, travel and illness draw on the same recovery capacity as training.

→ Why Recovery Matters for Performance
→ How to Train Smarter for Your Body

When should you see a GP?

Overtraining is a diagnosis made by ruling other things out. The consensus checklist includes checking for anaemia, iron deficiency, infections such as glandular fever, hormone problems and eating disorders. ¹

The NHS advises seeing a GP if: ⁴

• You have felt tired for a few weeks and cannot work out why
• Tiredness is affecting your daily life
• You also have other symptoms, such as weight loss or mood changes

A GP may suggest blood tests to check for things like anaemia or thyroid problems. ⁴ If low mood is persistent or you are struggling with food, please speak to a GP sooner rather than later.

What can you do next?

The best defence against overtraining is spotting the trend early. Tracking your sleep, resting heart rate and HRV over weeks can help you notice when recovery is slipping, so you can ease off before it becomes a bigger problem.

→ Explore the PhenomeTech Ring

To understand why recovery is where fitness is actually built, read the article below.

→ Why Recovery Matters for Performance