Sleep study: the AHI explained.

A sleep study screens for obstructive sleep apnoea (OSA) by measuring how often your breathing is interrupted overnight. The key result is the Apnoea–Hypopnoea Index (AHI): the average number of breathing pauses per hour of sleep. OSA is common, frequently undiagnosed, and an important, modifiable driver of cardiovascular and metabolic risk.

Why a sleep study matters

Untreated obstructive sleep apnoea fragments sleep and repeatedly drops oxygen levels, and is associated with hypertension, cardiovascular disease, insulin resistance, daytime fatigue and impaired cognition. Because it happens while you sleep, most people who have it do not know.

What the clinical evidence shows

• Peppard et al. (NEJM 2000): a landmark cohort showing a dose-response relationship between sleep-disordered breathing and the development of hypertension.
• Marin et al. (The Lancet 2005): severe untreated OSA was associated with markedly higher rates of fatal and non-fatal cardiovascular events, with risk reduced in those treated with CPAP.
• AASM scoring manual: defines the AHI thresholds used to grade OSA severity worldwide.

Evidence-based reference ranges

OSA severity is graded by the Apnoea–Hypopnoea Index (AHI). Events per hour of sleep:

Clinical interpretation

• An AHI of 5 or more suggests obstructive sleep apnoea; higher values indicate greater severity.
• At-home sleep tests are a validated screening tool; a formal diagnosis and treatment plan are made by a sleep physician.
• Effective treatment of moderate-to-severe OSA can improve blood pressure, energy, sleep quality and cardiovascular risk.

How this works at HodieLabs

An at-home sleep study is available as an add-on to any HodieLabs membership, with results reviewed by a doctor and integrated with your cardiovascular and metabolic markers at our Melbourne Preventative Health & Longevity Clinic.

References

1. Peppard PE, et al. Prospective study of the association between sleep-disordered breathing and hypertension. N Engl J Med. 2000;342:1378–1384.
2. Marin JM, et al. Long-term cardiovascular outcomes in men with obstructive sleep apnoea with or without CPAP. Lancet. 2005;365:1046–1053.
3. Berry RB, et al. AASM Manual for the Scoring of Sleep and Associated Events. American Academy of Sleep Medicine.

This page is general information from the HodieLabs Evidence-Based Clinical Library, not medical advice. Speak with your GP about what testing and care is appropriate for you.