Sources Healthify; Mayo Clinic
Fatigue is the feeling of exhaustion or lack of energy. It’s different from the feeling of sleepiness you get at bedtime, or tiredness after exercise or a late night. Fatigue affects most adults at some time – it can be due to physical illness, psychological causes or lifestyle factors.
Video: Fatigue, causes, signs and symptoms, diagnosis and treatment
Fatigue can cause a wide range of symptoms. These might include:
- feeling tired or sleepy all the time
- headache
- poor concentration
- slow reflexes
- blurry vision
- impaired judgement and difficulty making decisions
- feeling moody or irritable
- clumsiness or poor hand-eye coordination
- muscle pain
- feeling weak
- loss of appetite
- low motivation or general lack of interest
- seeing things that aren’t there (hallucinations).
Medical causes of fatigue
Fatigue can be a symptom of many medical conditions including:
- flu
- COVID-19 6624 and long COVID
- glandular fever 9713.18/6682
- myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) 9714
- coeliac disease 9713.19
- heart disease
- diabetes
- thyroid disorders
- anaemia
- pregnancy
- going through menopause 661621
- pain
- multiple sclerosis
- cancer or cancer treatment
- medication or a combination of medicines
- having a disturbed sleep pattern, eg, sleep apnoea 66.23, getting up in the night with an overactive bladder or prostate issue
Lifestyle causes can include:
- drinking too much alcohol or taking drugs
- poor sleep hygiene (external link)(eg, going to bed at irregular hours, too much noise or light)
- too much caffeine
- lack of exercise
- poor diet (eg, junk food)
Work related causes of fatigue
These could be:
- shift work (read more about sleep and shift work)
- poor workplace practices or environment (eg, long hours, hard physical labour, unsuitable environment)
- workplace stress, bullying, conflict or job insecurity
- unemployment.
Emotional causes of fatigue are common. It’s not unusual to feel fatigued if you’re experiencing:
- anxiety 9713
- grief 6624 or emotional shock 6619
- stress
- depression.
Neurodivergence and Fatigue (ALPIMS Note)
👉 Neurodivergence is not a problem—but it can increase total system load
In the ALPIMS framework, neurodivergence (e.g. autism, ADHD traits) often overlaps with multiple domains, especially:
- Sensory (S) – increased sensitivity or processing load
- Autonomic (A) – differences in regulation and arousal
- Mood (M) – anxiety, burnout, emotional intensity
- Sometimes Immune (I) and Pain (P) in overlapping conditions
Why Neurodivergent Fatigue Happens
Neurodivergent individuals often experience:
Higher Sensory Load
- More input coming in (noise, light, textures, smells)
- More effort needed to filter or tolerate environments
👉 Energy is used just processing the world
Increased Cognitive Load
- Constant thinking, pattern recognition, monitoring
- Executive function effort (planning, switching, organising)
👉 The brain is working harder, more of the time
Masking / Camouflaging
- Suppressing natural responses
- Adapting to social expectations
- Monitoring behaviour and communication
👉 This is extremely energy-intensive
Regulation Differences
- Faster overload (sensory or emotional)
- Longer recovery time after stress
👉 Capacity is used quickly and restored more slowly
How This Links to Fatigue
When neurodivergence is present:
👉 Baseline load is often higher
👉 Recovery may take longer
👉 Tolerance for additional stress is lower
So even “normal” life demands can lead to:
- Fatigue
- Shutdowns
- Burnout
- Reduced capacity over time
⚠️ Important Reframe
❌ Neurodivergence is not the cause of fatigue
✅ Unmet needs + environmental mismatch + overload → fatigue
What Helps (ALPIMS-Aligned)
- Reducing sensory load (environment, products, noise)
- Allowing authentic behaviour (less masking)
- Structuring life around capacity (not expectations)
- Supporting regulation (rest, pacing, predictability)
