Epworth Sleepiness Scale (ESS)

The ESS is an 8-item questionnaire measuring daytime sleepiness across everyday situations. Scores >10 indicate excessive daytime sleepiness warranting evaluation for sleep apnea, narcolepsy, or hypersomnia. Johns (1991). Freely available for clinical use.

What is the Epworth Sleepiness Scale?

The Epworth Sleepiness Scale (ESS) was developed by Dr. Murray Johns at Epworth Hospital in Melbourne, Australia, and first published in Sleep in 1991. It measures an individual's general level of daytime sleepiness – also called somnolence, by asking them to rate, on a 0–3 scale, their chance of dozing in eight different everyday situations ranging from sitting quietly to driving in traffic.

Unlike actigraphy or polysomnography, the ESS captures the subjective propensity to fall asleep, a clinically meaningful dimension distinct from objective sleep duration. ESS scores correlate with multiple sleep disorder diagnoses including Obstructive Sleep Apnea (OSA), narcolepsy, idiopathic hypersomnia, and periodic limb movement disorder. A total ESS score above 10 is the widely accepted threshold for excessive daytime sleepiness warranting further sleep evaluation.

The ESS is freely available for clinical and research use from Dr. Johns' official website (epworthsleepinessscale.com). It has been translated into more than 50 languages and validated across diverse clinical populations. The ESS score alone does not diagnose a sleep disorder, it is a screening tool that guides decisions about polysomnography (sleep study) or additional evaluation.

Rate your chance of dozing in each situation using the 4-point scale below. Answer based on your usual recent lifestyle.

ESS Score Reference

Johns (1991). ESS cutoffs are well-validated across sleep disorder populations. Scores should be interpreted in context of clinical history and examination.

Score Interpretation

The ESS total ranges from 0 to 24 (eight items, each scored 0–3). A total of 10 or below falls in the normal range; a score above 10 indicates excessive daytime sleepiness that warrants further sleep evaluation (Johns, 1991). The commonly applied severity gradation is:

• 0–5 — lower normal daytime sleepiness
• 6–10 — higher normal daytime sleepiness
• 11–12 — mild excessive daytime sleepiness
• 13–15 — moderate excessive daytime sleepiness
• 16–24 — severe excessive daytime sleepiness

Rating Scale

Each of the eight situations is rated for the chance of dozing on a 4-point scale: 0 = would never doze, 1 = slight chance, 2 = moderate chance, 3 = high chance.

Sleep Conditions Associated with High ESS

Elevated ESS scores are seen in obstructive sleep apnea, narcolepsy, idiopathic hypersomnia, and periodic limb movement disorder. In the original validation, ESS scores significantly distinguished these diagnostic groups from controls and correlated with objective sleep-latency measures, while the scores of people who only snored did not differ from controls (Johns, 1991).

Sleep Assessment Tools

The ESS is often paired with the Insomnia Severity Index (ISI) and the Pittsburgh Sleep Quality Index (PSQI) for a fuller sleep profile, and with the PHQ-9 to capture comorbid depression.

An ESS score above 10, especially with snoring, witnessed apneas, morning headaches, or non-restorative sleep, warrants referral to a sleep specialist or primary care evaluation for polysomnography. Do not drive or operate heavy machinery if you are experiencing excessive sleepiness. Untreated sleep apnea is associated with significantly elevated risk of motor vehicle accidents, cardiovascular disease, and metabolic syndrome.

Sleep Outcome Monitoring in HiBoop

ESS, ISI, PSQI, and PHQ-9, integrated sleep and behavioural health outcome monitoring for sleep medicine, pulmonology, and primary care programs.