Why Overtraining Is Killing Your Progress
Move Sports Physiotherapy & Pilates Geelong
More isn't always better
Fitness is built during recovery, not during the session itself. Training is the stimulus; rest, sleep and food are where your body actually adapts. Pile on more stress than you can recover from, and progress stalls or goes backwards.
That's the frustrating paradox many committed runners and gym-goers hit. You're training harder than ever, yet your times are getting slower, your legs feel heavy, you're sleeping badly and you've had three colds this season. The instinct is to push harder. Often, the answer is the opposite.
This post covers what overtraining actually is, what it looks like, and why comparing yourself to others (including on apps like Strava) actually kills your own performance.
What is overtraining?
The 2013 joint consensus statement from the European College of Sport Science and the American College of Sports Medicine (ECSS/ACSM) describes overtraining in three stages (Meeusen et al. 2013):
Functional overreaching
A deliberate block of hard training causes a short-term dip in performance. After adequate recovery, you bounce back fitter than before. This is how good training programs are meant to work.
Non-functional overreaching (NFOR)
You've pushed too hard for too long without enough recovery. Performance stays depressed, and when you finally recover, you're no better than your starting point (Frontiers in Sports and Active Living). All that extra work bought you nothing.
Overtraining syndrome (OTS)
The extreme end: a long-term fall in performance, often with hormonal, immune and mood disturbances. Recovery estimates are vague but range from months to years (systematic review, Psychology of Sport and Exercise 2026).
A surprising point from the consensus: NFOR and OTS can't be told apart by symptoms or the type of training. They can only be distinguished in hindsight, by how long recovery takes (Frontiers). That's why catching the warning signs early matters so much.
Under-fuelling looks a lot like overtraining.
A 2021 review by leading researchers found that overtraining and Relative Energy Deficiency in Sport (RED-S) share many pathways, symptoms and diagnostic challenges, both driven from the brain's hormonal control centre and both influenced by low carbohydrate and energy intake (Stellingwerff et al., Sports Medicine 2021). In plain terms: many people who think they're "overtrained" are actually under-fuelled for the training they're doing. Often, it's both.
What does overtraining look like?
The hallmark sign is unexplained underperformance: you're training consistently, but getting slower or weaker, and it doesn't bounce back after a few easy days.
Alongside that, overtraining typically brings general fatigue, mood disturbance, poor sleep, and more frequent illness and injury, which persist despite more than two weeks of rest .
Area | What you might notice |
Performance | Slower times at the same effort; sessions that used to feel easy feel hard; heart rate struggles to rise in hard efforts |
Energy | Heavy, "dead" legs that don't freshen up after easy days; constant tiredness |
Mood | Irritability, low motivation, dreading training, anxiety or low mood |
Sleep | Difficulty falling or staying asleep, or long sleep that still leaves you unrefreshed |
Immunity | Frequent colds, sore throats or lingering infections |
Body | Persistent muscle soreness, niggles that turn into injuries, appetite changes, unintended weight loss |
Heart rate | Resting heart rate noticeably higher (or sometimes unusually lower) than your normal; lower heart rate variability |
Hormones | For women, missed or irregular periods (a red flag for under-fuelling) |
A real-world case series of three endurance athletes with overtraining syndrome described symptoms ranging from chronic fatigue, muscle cramping and dizziness to repeated respiratory infections and disrupted sleep (case series, 2025). One of them ignored his symptoms, kept training and raced anyway, only for the same symptoms to return and force him out mid-race.
Why overtraining kills your progress
Overtraining doesn't just stall you; it actively costs you fitness, time and health.
You never cash in the adaptation
Training breaks you down; recovery builds you back stronger. The consensus statement is clear that successful training needs overload, but must avoid the combination of excessive overload plus inadequate recovery (Meeusen et al. 2013). Skip the recovery half and you pay the cost of hard training without the payoff.
Injury risk climbs, often in a single session
The largest running injury study to date, the Garmin-RUNSAFE project, followed 5,205 runners from 87 countries over 18 months and more than 588,000 logged runs (Aarhus University). Injury risk rose significantly when a single run was more than 10% longer than the runner's longest run in the previous 30 days (Frandsen et al., BJSM 2025). Small spikes (10–30% over) and moderate spikes (30–100%) raised risk, and very large spikes raised it most (Conexiant summary).
Interestingly, weekly mileage ratios showed no clear link with injury. It's the single overambitious run that bites.
Illness and lost weeks add up
Frequent colds, poor sleep and persistent niggles all mean missed sessions. A few weeks of consistent, moderate training beats a cycle of hard blocks followed by forced time off.
Recovery takes far longer than the damage
Functional overreaching resolves in days to weeks. Non-functional overreaching can take weeks to months, and full overtraining syndrome months to years (Psychology of Sport and Exercise 2026). A few weeks of "extra" training can cost you a season.
Motivation erodes. Mood disturbance, dread and loss of enjoyment are core features of overtraining. For recreational athletes, losing the joy of training is often the biggest cost of all.
The comparison trap: why other people's data is wildly unhelpful
The only training data that matters for your progress is your own. Someone else's pace, distance or weekly volume tells you almost nothing about what you should be doing, yet it's one of the most common reasons people end up overtraining.
Apps like Strava cut both ways
A 2026 mixed-methods study of club runners found Strava helped with feedback, routine and social connection, but also introduced pressure, comparison and stress, especially during injury or poor form (Behavioral Sciences 2026). Leaading to unneccessary stress and poor training and recovery decisions.
We copy what we see
A study using Strava's own data found runners were influenced by, and tended to mimic, the running behaviour of the clubmates they exchanged kudos with (Franken et al., Social Networks). That social pull can be motivating, but it also means your training starts to drift toward someone else's plan rather than yours.
You're seeing a highlight reel
In the same club-runner study, several participants said they deliberately hid sessions or limited interactions to avoid comparison (Behavioral Sciences 2026). The feed you scroll is curated: the fast interval session makes it on, the shuffling recovery jog or the week off with a sore Achilles often doesn't.
What you see on someone's feed | What you don't see |
A fast "easy" run pace | Their years of training, genetics, body size, the terrain, a tailwind or a GPS glitch |
A big weekly total | The months of gradual build-up, or the injury that followed |
Terrain | You don’t see accurate details of terrain, conditions, hills etc. |
Behind the scenes | Sleep, pre & post fuelling, general nutrition habits, coaching, short and long-term planning. |
Compare with yourself instead
Track your own trends: how your pace at a given heart rate or effort changes, how you feel, how you sleep. Consider hiding pace on your public activities, muting accounts that make you feel behind, or taking a break from the feed during injury or a hard training block.
How to avoid overtraining
You don't avoid overtraining by training less; you avoid it by balancing load with recovery and noticing early when that balance tips.
1. Build gradually, and watch single-session jumps
Increase load steadily rather than in big leaps. For runners, a simple rule from the Garmin-RUNSAFE data: keep any single run within about 10% of your longest run in the past 30 days (Frandsen et al., BJSM 2025). The same logic applies to lifting: add weight, sets or sessions one at a time.
2. Keep easy days easy and hard days hard
Most of your training should be at a relaxed, conversational effort, with a small number of genuinely hard sessions. This "mostly easy, some hard" approach, often described as 80/20, is well supported in recreational runners (Muñoz et al. 2014). If you can't hold a conversation on an easy run, slow down, whatever your watch or your mates' data says.
3. Plan recovery, don't just hope for it
Schedule rest days and lighter weeks before you need them. Many coaches build in an easier week every three to four weeks. Planned hard blocks are fine, provided they are followed by genuine recovery.
4. Fuel the work
Under-eating, and low carbohydrate intake in particular, drives many of the same symptoms as overtraining (Stellingwerff et al., Sports Medicine 2021). Eat enough to match your training, especially around hard or long sessions, and don't combine a big training block with a diet. Unsure, speak to a registered nutritionist to assess your fuelling needs.
5. Protect your sleep
Sleep is when much of your repair happens. Consistent sleep and wake times, and enough total hours, are among the most powerful recovery tools available.
6. Count life stress as training stress
Your body doesn't separate a hard interval session from a stressful work deadline, a new baby or a house move. When life is demanding, pull back training to match.
7. Listen to how you feel
A systematic review of 56 studies found that simple self-reported measures, like mood, fatigue, stress and soreness, were more sensitive and consistent at tracking the training response than commonly used objective measures (Saw et al., BJSM 2016; summary, Frontiers in Psychology). Watch data such as resting heart rate and HRV can add useful context, but trends over weeks matter more than any single reading, and they shouldn't override how you actually feel.
A quick daily check-in (rate each 1–5):
How well did I sleep?
How fresh do my legs feel?
How is my mood and motivation?
How stressed am I outside training?
If your scores stay low for several days, or your performance is dropping, swap the next hard session for an easy one or a rest day. Two or three easy days now can save you weeks later.
Key points and when to get help
Progress comes from the training you can recover from, not the most training you can do. Keep easy days easy, avoid big single-session jumps, fuel and sleep well, and compare yourself with your past self rather than someone else. If your performance has dropped for more than two to three weeks despite rest, or you're dealing with ongoing fatigue, frequent illness, low mood or (for women) missed periods, it's time to get it checked.
References
Meeusen R, et al. Prevention, diagnosis and treatment of the overtraining syndrome: joint consensus statement of the ECSS and ACSM. Eur J Sport Sci 2013. Link
Planned overreaching and the overtraining continuum. Frontiers in Sports and Active Living. Link
Effects of non-functional overreaching and overtraining syndrome on psychological and cognitive functioning in elite athletes: a systematic review. Psychology of Sport and Exercise 2026. Link
Stellingwerff T, et al. Overtraining Syndrome (OTS) and Relative Energy Deficiency in Sport (RED-S): shared pathways, symptoms and complexities. Sports Medicine 2021. Link
Overtraining syndrome: an overview. ScienceDirect Topics. Link
Overtraining syndrome in three endurance athletes and roads to recovery. Case series, 2025. Link
Frandsen JSB, et al. How much running is too much? Identifying high-risk running sessions in a 5200-person cohort study. Br J Sports Med 2025. Link
Aarhus University. Everything we thought about running injury development was wrong, study shows. Link
A mixed-methods analysis of motivational dynamics and Strava use in active club runners. Behavioral Sciences 2026. Link
Franken R, et al. Kudos make you run! How runners influence each other on the online social network Strava. Social Networks. Link
Muñoz I, Seiler S, et al. Does polarized training improve performance in recreational runners? Int J Sports Physiol Perform 2014. Link
Saw AE, Main LC, Gastin PB. Monitoring the athlete training response: subjective self-reported measures trump commonly used objective measures: a systematic review. Br J Sports Med 2016. Link
Associations between subjective and objective measures of stress and load: a 45-week prospective study in 189 elite athletes. Frontiers in Psychology. Link
