Trail Notes | Recovery & Injury Prevention

the recovery you cannot skip

Sleep

& Injury Risk.

If you had been told that one recovery variable was associated with a meaningful increase in injury risk every time it worsened by a single point on a weekly quality scale, you would treat it as a critical training input. That variable is sleep. And many runners are still not treating it that way.

In Her Trails, we spend a lot of time helping athletes refine their training, their fuelling, their pacing strategy, and their strength work. All of those things matter. But there is an ingredient that sits underneath all of them, without which none of them function at full capacity. Sleep is not passive recovery. It is the period during which your body does most of its actual repair work, and the evidence for its relationship with running injury risk is now more precise and more compelling than many coaches have communicated.

This Trail Note is for the runner who trains hard and recovers seriously, but may still be undervaluing what happens in those eight hours.

Trail Note  ·  01

What the research actually shows

A 2025 prospective study by Goldberg and colleagues followed 339 adult runners over a 26-week period and examined the relationship between weekly recovery markers and running-related injury risk. Runners reported injuries weekly and completed a short recovery questionnaire assessing sleep quality, sleep quantity, sleep latency, fatigue, muscle soreness and perceived stress.

The key finding: poorer weekly sleep quality was significantly associated with increased running-related injury risk. Each one-point worsening in sleep quality score was associated with a 36% increase in injury risk. Importantly, in this model, sleep quantity was not significantly associated with injury risk.

A separate 2025 study by de Jonge and Taris looked at 425 recreational runners and used sleep duration, sleep quality and sleep problems to identify four sleep profiles: Steady Sleepers, Poor Sleepers, Efficient Sleepers and Fragmented Sleepers.

Poor Sleepers were significantly more likely to report a sports injury than Steady Sleepers. Their odds of injury were 1.78 times higher, with an estimated injury probability of 68%, compared with 55% in the Steady Sleepers group. That distinction matters. It suggests that sleep should be viewed as a multidimensional recovery signal, not simply a matter of getting enough hours.

Trail Note  ·  02

Why sleep disruption may increase injury risk: the mechanisms

The relationship between sleep and injury is not simply about tiredness causing clumsiness, though that can contribute. Sleep influences multiple biological systems that matter for training adaptation, tissue repair and injury resilience.

Growth hormone release is strongly linked with deep sleep and plays an important role in tissue repair, muscle adaptation and recovery from training. Poor sleep quality, particularly fragmented sleep or reduced slow-wave sleep, may reduce the body’s capacity to complete that repair work. You train. The signal for adaptation goes out. But without enough restorative sleep, the response may be incomplete.

Cortisol regulation is also affected by poor sleep. Cortisol should follow a healthy daily rhythm, typically lower overnight and rising in the morning to support alertness. Disrupted or insufficient sleep can disturb that rhythm, increasing physiological stress and potentially impairing recovery.

Neuromuscular recovery is another part of the picture. Sleep supports reaction time, coordination, motor learning and proprioceptive control, all of which matter when running on trails, descending technical terrain, or holding form under fatigue. The key point is not that poor sleep is the only cause of injury. It is that poor sleep can reduce the capacity of the body to absorb training load. And once load exceeds capacity, injury risk rises.

Trail Note  ·  03

Quality versus duration: why this distinction matters

Both studies found that sleep quality was a stronger predictor of injury risk than sleep duration. This matters because the common advice around sleep for athletes is framed almost entirely in terms of hours: “get eight hours.” Hours in bed is a proxy. It is not the same as restorative sleep.

You can spend eight hours in bed with poor sleep architecture (not enough slow-wave sleep, frequent micro-arousals, difficulty falling back to sleep after waking) and wake with the hormonal profile and neuromuscular recovery of someone who slept far fewer hours. The tissue repair signal (growth hormone) requires slow-wave sleep specifically. The nervous system consolidation requires continuous sleep cycles. Duration without quality does not deliver the same physiological outputs.

The practical implication: if you are spending eight hours in bed but waking unrefreshed, still feeling heavy in training, and picking up nagging injuries, the quality question is worth investigating. Duration is necessary but not sufficient.

Trail Note  ·  04

The perimenopause layer

For many women in the Her Trails community, this research may feel particularly relevant. Sleep disruption is commonly reported through perimenopause and menopause, and it is often linked with hormonal fluctuation, vasomotor symptoms, stress physiology and changes in mood.

Night sweats and hot flushes can interrupt sleep continuity. Changing oestrogen and progesterone levels can influence sleep quality, temperature regulation and mood. Anxiety, which many women report during this transition, can also make it harder to fall asleep or return to sleep after waking.

This means some perimenopausal trail runners may be managing several overlapping recovery challenges at once: changing sleep quality, heavier stress load, altered muscle and tendon recovery, changes in body composition, and in some cases, bone density considerations. These are not separate issues. They can compound.

If you are in perimenopause and finding that recovery feels harder, nagging injuries are appearing more often, or the same training load you handled a few years ago now feels different, there may be a biological explanation. It is not weakness. It is information.

Trail Note  ·  05

Sleep and the total load picture

Most athletes think about training load in terms of kilometres, hours, elevation, and intensity. These are the inputs. But load management also requires an honest accounting of recovery, and sleep is the single most impactful recovery variable we have access to.

A week with high training volume and good sleep can produce a very different physiological outcome from the same week with poor sleep. The training stimulus may be the same. The recovery output is not. Poor sleep does not necessarily add kilometres to your week, but it can reduce the capacity you have to absorb those kilometres.

Running injuries rarely emerge from one isolated factor. They tend to develop when the load placed on tissue exceeds what that tissue can currently tolerate, repair and adapt to. Poor sleep quality may shift that equation by lowering recovery capacity, even when training volume has not changed. You do not have to do more to be at higher risk. You may simply have to recover less.

Trail Note  ·  06

What shifts sleep quality: the factors within your influence

Not all sleep disruption is within your control, and it is important to be clear about that. Vasomotor symptoms in perimenopause, young children, shift work, and medical conditions all create barriers that simple sleep hygiene advice does not resolve. If chronic sleep disruption is significantly affecting your quality of life, a conversation with your GP or a sleep specialist is the appropriate next step, particularly in the context of perimenopause where there are clinical interventions available.

But for many athletes, sleep quality is being degraded by factors that are genuinely within influence. Alcohol, which suppresses REM sleep and fragments sleep architecture in the second half of the night, is one of the most common. High training load in the evening, which elevates core body temperature and sympathetic nervous system arousal before sleep, is another. Inconsistent sleep timing, which undermines circadian rhythm signals, is a third.

Trail Note  ·  07

Sleep as a training variable, not a recovery add-on

The framing shift that the evidence supports is this: sleep is not what you do after training. Sleep is part of training. It is when the adaptation to training happens. Growth hormone, collagen synthesis, muscle protein synthesis, neuromuscular pattern consolidation, immune regulation: all of these are sleep-dependent. The training session is the stimulus. Sleep is the response.

A session that is not followed by quality sleep is a session that did not fully adapt to. You got the stress. You did not fully bank the response. Over weeks and months, this creates a growing gap between the load you are accumulating and the adaptations you are completing, which is the precise condition that precedes injury.

Treating sleep with the same intentionality that you bring to your training sessions is not excessive. It is proportionate to the evidence.

Trail Note  ·  08

Practical signals: is your sleep quality a risk factor right now?

The following are not diagnostic criteria. They are patterns worth paying attention to, particularly in the context of a high training load phase or if injury is present or recurrent.

Sleep does not feel like a training intervention because it is quiet. You do not feel it happening. It does not have a Strava segment. You cannot compare your eight hours with someone else’s hill reps.

And yet it is one of the windows where your body decides whether the training you did today becomes adaptation, or simply adds to a growing recovery debt. The most injury-resistant version of yourself is not the athlete who only trains harder. It is the athlete who trains with intention, fuels consistently, builds structural strength, respects life load and protects sleep as part of the program.

Not because wellness culture says sleep matters. Because the biology, and the emerging running-specific evidence, says it does.

train it. fuel it. sleep it. that is the whole program.

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