Good sleep cuts crash risk by nearly a third, Discovery study finds

Getting enough sleep can reduce motor vehicle accident risk by up to 32%, and sleep health is a fivefold stronger predictor of motor vehicle accident risk than demographic or credit factors.

These are the findings of a sleep study by Discovery drawn from over 47-million sleep records from 105,000 people collected from wearable devices over several years, making it one of the most comprehensive analyses of its kind. Discovery Insure’s telematics data linked sleep patterns to motor-vehicle accident risk and driving behaviour.

Sleep is not only essential for long-term health but directly influences everyday behaviour — especially driving, according to the study. Adequate sleep supports key cognitive functions such as alertness, attention, decision-making, and reaction time, all vital for safe driving.

Severe sleep deprivation can impair driving ability to the same degree as being over the legal blood-alcohol limit, the study noted.

External research aligned with Discovery’s study, finding that sleeping only four to five hours per night increases crash risk by 4.3 times.

The growing popularity of wearable devices such as smartwatches and smart rings has made sleep tracking more accurate and accessible.

These tools can measure sleep duration, quality and timing, offering insights that can help users improve their sleep health and, ultimately, their driving safety.

“Most adults require seven to nine hours of actual sleep per night for optimal health outcomes — a figure that excludes time spent in bed before falling asleep,” said the report.

While awareness of healthy sleep is growing, sleep disorders are becoming increasingly common both globally and in SA. The most prevalent are insomnia and obstructive sleep apnoea (OSA).

Insomnia involves persistent difficulty falling or staying asleep, leading to poor sleep quality, daytime fatigue, and impaired functioning.

OSA occurs when the upper airway collapses during sleep, interrupting breathing and causing frequent awakenings and low oxygen levels.

Globally, about 12% of adults suffer from insomnia, and 36% of older adults are affected by OSA.

Discovery Health Medical Scheme data reflects these global trends:

• Sleep disorder claims have increased 2.8 times between 2008 and 2024.

• Insomnia accounts for 55% of all primary sleep disorder claims and is growing by 4.7% annually.

• OSA makes up 12% of claims but is the fastest-growing disorder, increasing by 9% per year.

• Modern lifestyles have dramatically reshaped the way we sleep, said Discovery.

“Irregular schedules, artificial lighting, stress and constant digital stimulation have disrupted natural sleep patterns, making restful sleep increasingly elusive,” said the study.

“One in three adults fails to achieve the recommended amount of sleep, and even those who do often struggle with inconsistent sleep timing or poor sleep quality.”