Invisible conditions at work: why output is masking a growing health risk 

One in three people of working age in the UK is living with a long-term health condition. Yet many of those conditions remain unseen at work. 

“Invisible” or “non-visible” disability is not a clinical category, explains Hugh O’Keeffe, inclusion lead at Onvero. “It is a social descriptor referring to conditions that are not immediately apparent to others.” 

Clinically, this can include autoimmune disease, chronic pain and epilepsy, alongside neurodevelopmental and mental health conditions. Office for National Statistics data show that the most cited impairments among disabled working-age adults are mobility, mental health and stamina or breathing-related conditions. Many fluctuate. Many are not outwardly visible. 

The gap between prevalence and workplace recognition is stark. While 24 per cent of working-age adults meet the Equality Act 2010 definition of disability, organisational disclosure rates are typically lower. 

Definitions themselves can create blind spots. O’Keeffe cautions against narrowing invisibility to mental health or neurodiversity alone. “Many physical and neurological conditions are episodic or subtle. In occupational contexts, diagnostic labels are often foregrounded, yet the Equality Act focuses on functional impact. From a workplace perspective, what matters is how a condition affects stamina, concentration, mobility and reliability across a working week.” 

That distinction; diagnosis versus function, is critical for employers seeking to link inclusion with workplace health and wellbeing. 

The hidden workload 

Traditional performance systems are built around consistency, speed and visible output. But invisible conditions often operate on a different rhythm. 

Georgie Spurling, CEO and founder of ARVRA talks about these conditions: “Invisible conditions in research are typically defined as long-term physical or mental health conditions that aren’t immediately visible – chronic pain, autoimmune conditions, ADHD, anxiety, endometriosis, migraines. But definitions often centre diagnosis, not day-to-day impact. And that’s where they fall short. Many people spend years undiagnosed, still symptomatic, still working, still suffering. In the UK, prevalence among working-age adults is significant, particularly mental health conditions, neurodivergence, and chronic pain-related disorders. The evidence is strong on diagnostic delay and symptom fluctuation, but weaker when it comes to longitudinal, workplace-specific impact.”

She adds: “What we do know is that invisible conditions increase cognitive load, fatigue and emotional regulation demands; even when performance looks “fine”. Traditional metrics miss the hidden effort. Sadly, disclosure remains low, largely due to stigma and job insecurity. So the real question is: why are we still designing support around disclosure? Where we’ve had success is where we focus on measuring patterns of pressure and impact without requiring people to formally label themselves; because prevention shouldn’t depend on vulnerability.”

“Non-visible disabilities are not a coherent clinical grouping,” O’Keeffe adds. “They encompass conditions with very different underlying mechanisms. It would therefore be inaccurate to assign a single cognitive or behavioural profile to them.” 

Research does, however, highlight some common experiences. Managing a stigmatised but non-visible condition can increase cognitive burden and emotional strain. Concealment requires vigilance, and masking behaviours; particularly among autistic adults, have been linked to exhaustion and psychological stress. 

Fatigue and cognitive variability are also widely documented across many long-term conditions. NICE guidance for multiple sclerosis, chronic fatigue syndrome and depression all identify fatigue and concentration difficulties as core features. 

The result is a structural mismatch between how work is measured and how many long-term conditions affect day-to-day functioning. 

“Traditional performance metrics tend to prioritise consistency, speed and visible output,” O’Keeffe explains. “They rarely account for fluctuating capacity or recovery time. This creates a structural mismatch between how work is measured and how many long-term conditions affect day-to-day functioning.” 

In practice, this means employees may appear productive while operating at significant physiological or psychological cost. 

Dr Tijion Esho, founder of Cultskin, describes this as “invisible load.” 

“Invisible health conditions are increasingly defined as long-term, often fluctuating conditions that are not outwardly observable but significantly affect energy, cognition, mood and physiological resilience.” 

He includes autoimmune disease, endometriosis, migraine, fibromyalgia, long Covid, mental health conditions and menopause-related syndromes among those highly prevalent in working-age adults, particularly women.  “The limitation is that definitions remain overly diagnostic, rather than functional and systems based. Many invisible conditions represent chronic dysregulation across inflammatory, hormonal, metabolic or neurological pathways, long before they are formally labelled.” 

From a longevity and workplace wellbeing perspective, the risk is clear: output can remain stable while resilience declines. 

Diagnostic delay and career cost 

Diagnostic delay compounds the problem. Endometriosis, autoimmune disease and perimenopause are well-documented examples where symptoms are normalised or dismissed. 

“Diagnostic delay is one of the most damaging features of invisible conditions, especially in women’s health.” 

“The consequences are profound: prolonged physiological stress, worsening inflammation, mental health burden and reduced long-term healthspan.” 

In working life, this often translates into fragmented careers, reduced confidence, higher presenteeism and eventual workforce exit. 

“Traditional performance metrics fail because they measure output, not physiological cost.” 

“Many individuals remain highly capable but expend disproportionate energy simply maintaining baseline functioning, a hidden workload that is rarely acknowledged.” 

Energy, work design and women’s health 

For Bianca Best, the conversation around invisible conditions is inseparable from how organisations understand energy at work. 

“In my work, I encourage organisations to measure energy, not illness – and Self-Determination Theory gives us a powerful, non-intrusive framework to do exactly that.” 

She points to three factors that determine whether energy is replenished or depleted in the workplace. “Autonomy, competence and connection are not ‘soft’ concepts; they are reliable indicators of whether energy is being replenished or depleted at work.” 

When these conditions are missing, employees managing invisible conditions often carry additional strain. 

“When autonomy is low, people with invisible conditions burn energy by masking, over-adapting and pushing through. And when connection and a sense of safe collaboration is weak, nervous systems stay in threat, driving fatigue, emotional dysregulation and disengagement.” Best adds.  

Workplace structures can also clash with the physiological realities many employees experience. Best says:  

“Having worked over the past decade with ambitious women at every career stage, with organisations from global behemoths, sole traders to buzzing start-ups, I firmly believe the issue isn’t just hormones, but primarily gross energy misalignment.” 

“Hormonal cycles, reproductive health and life-stage transitions directly influence our energetic rhythms which in turn impact our cognitive capacity, emotional regulation, sleep, pain thresholds, recovery time and more.” 

Yet many workplaces still assume consistent capacity. 

“Yet most workplaces are still designed around a flat, uninterrupted model of capacity that assumes consistency rather than cyclical reality.” She says.  

When these rhythms go unsupported, the consequences accumulate over time. 

“The evidence shows that when biorhythmic fluctuations go unsupported, women compensate by borrowing energy, pushing through, masking symptoms and over-functioning.” 

“My work shows me time and time again that women don’t step back because they lack ambition. They step back because the energetic cost of staying becomes unsustainable.” 

When work is redesigned around pacing and recovery, the outcome can look very different. 

“When work is redesigned to allow pacing, flexibility and recovery – rather than constant, often near-impossible output – women don’t just stay; they thrive.” Best notes.  

Disclosure without safety 

Despite the scale of long-term health conditions in the working-age population, disclosure remains low. 

“There is a well-documented gap between disability prevalence and disclosure in the workplace,” says O’Keeffe. “Fear of stigma, limited career progression and negative managerial attitudes remain significant barriers.” 

For non-visible conditions, disclosure often requires explanation and validation. Anticipated discrimination influences decisions about whether to speak up. 

This raises a difficult question: should support depend on formal disclosure? 

“Adjustment processes are most effective when they are normalised rather than exceptionalised,” O’Keeffe says. 

“The Equality Act places a duty on employers where they know, or could reasonably be expected to know, that an employee is disabled.” 

Dr Esho agrees that the most effective models focus on function rather than proof. 

“Employees are more likely to disclose when workplaces are psychologically safe and adjustments are normalised rather than exceptional.” 

“Occupational health should focus less on proof and more on function: what does this person need to thrive sustainably?” 

Measuring what matters 

For employers, the challenge is understanding the impact without becoming intrusive. 

Best argues that organisations should focus on sustainable capacity rather than illness reporting. 

“Employers can track these dynamics through proxy measures: control over time and workload, clarity of expectations, psychological safety, recovery time after intense periods, retention and burnout-related exits, for example.” 

From a health perspective, she says the most important outcome is long-term sustainability. “From a health perspective, the outcome that matters most is sustainable capacity – the ability to consistently contribute without long-term depletion.” 

The economic implications are just as significant. “Energy is not a wellbeing add-on; it is the infrastructure of performance,” Best says.  

Redesigning for fluctuating capacity 

The common thread across these perspectives is a shift from diagnosis to function, from disclosure to design and from short-term output to long-term sustainability. 

Invisible conditions intersect with ageing workforces, women’s health, neurodiversity and chronic illness, all central themes in UK workplace health and wellbeing. 

For employers, the risk is not only legal or reputational. It is strategic. 

When work is structured around constant output and linear capacity, those managing fluctuating conditions carry a hidden workload. 

“From a workplace perspective, what matters is functional impact,” O’Keeffe reiterates. “How does this affect someone’s ability to sustain performance across a working week?” 

If organisations continue to measure only what is visible, they risk overlooking what is driving fatigue, disengagement and workforce exit beneath the surface. 

Invisible conditions may not be immediately apparent. But their impact on energy, trust and long-term performance is increasingly difficult for organisations to ignore.