Obstructive sleep apnea (OSA) has been a contentious topic in commercial driving for two decades. Federal regulations do not specifically require sleep apnea screening, but DOT medical examiners must evaluate any condition that could cause excessive daytime sleepiness — and OSA is the most common such condition.
When examiners screen for OSA
FMCSA medical advisory guidance recommends screening drivers with: BMI over 33; neck circumference greater than 17 inches (men) or 16 inches (women); reported loud snoring or witnessed apneas; observed daytime sleepiness; uncontrolled hypertension; or age over 42 with multiple risk factors. Screening is typically done with the Epworth Sleepiness Scale plus physical-exam findings.
If you screen positive
You'll be referred for a polysomnography (formal sleep study) or a home sleep test. The result is reported as an Apnea-Hypopnea Index (AHI) — the number of apnea or hypopnea events per hour of sleep. AHI under 5 is normal, 5–15 is mild OSA, 15–30 is moderate, and over 30 is severe. Mild OSA without daytime symptoms typically does not affect certification.
CPAP therapy and certification
Drivers with moderate or severe OSA must demonstrate CPAP compliance — at least 4 hours of CPAP use per night on at least 70% of nights — to maintain CDL medical certification. Modern CPAP machines record compliance data automatically; bring the SD card or compliance report to your DOT physical. Most compliant CPAP users receive 12-month medical cards (rather than the standard 24 months).
What happens if you refuse
If you refuse evaluation or refuse CPAP therapy when prescribed, you'll be denied medical certification until you comply. You may seek a second opinion from a different examiner, but most examiners will reach the same conclusion based on the same risk factors.
Practical advice
If you're a heavy snorer, often tired during the day, or have multiple risk factors, get evaluated by a sleep medicine doctor before your DOT physical — not at it. Showing up with a confirmed diagnosis and 90 days of compliant CPAP use is the fastest path to keeping your medical card.