The US Centers for Disease Control and Prevention (CDC) reports that 30% of the nation’s workers are sleeping under 6 hours a day, which is less than the 7 to 9 hours that the National Sleep Foundation recommends for healthy adults.

To assess the prevalence of insufficient sleep among US workers, the CDC analyzed data from the 2010 National Health Interview Survey (NHIS). They published the results in the 27 April issue of their Morbidity and Mortality Weekly Report (MMWR).

Insufficient sleep is an important public health issue: it can have serious and sometimes fatal consequences for tired workers and the people around them.

For instance, according to the CDC, some 20% of motor vehicle crashes are linked to drowsy driving.

For their analysis of the NHIS data, the CDC looked at reported sleep duration according to age, gender, race/ethnicity, marital status, education and employment characteristics (eg industry sector and usual shift working).

Among other things, they found that:

Overall, 30.0% of employed US adult civilians (about 40.6 million workers), said they slept on average no more than 6 hours a day.

The proportions reporting sleeping less than 6 hours a day varied by industry (ranging from 24.1% in “other services, except public administration”, to 41.6% in mining).

There was a significantly higher rate of short sleep duration among manufacturing workers (34.1%) compared to all workers combined.

Workers who worked night shifts had a much higher rate of short sleep duration (44.0%, or about 2.2 million workers) than workers who worked day shifts (28.8%, or 28.3 million workers).

Especially high rates of insufficient sleep were reported by transportation and warehousing night shift workers (69.7%), and by workers in the health care and social assistance sector (52.3%).

Of racial/ethnic groups, non-Hispanic white workers (28.6%) and Hispanic workers (28.8%) were the least likely to report not getting enough sleep, compared to non-Hispanic black workers (38.9%), non-Hispanic workers of other races (35.3%), and non-Hispanic Asian workers (33.2%).

Widowed, divorced and separated workers (36.4%) were significantly more likely to report sleeping 6 hours a day or less than married (29.4%) and never-married (28.2%) workers.

Workers who had attended high school or college reported less sleep shortages than those that either hadn’t attended high school or college or those that went on to further education afterwards.

Workers with more than one job were significantly more likely to report short sleep duration than those with just one job.

Working more than 40 hours a week was also linked to being more likely to report short sleep duration.

In an editorial note, the CDC point out that studies propose several reasons for why short sleep duration is linked to shift working and particular industry sectors.

One reason is that the more hours a person works, the less opportunity there is for the right proportion of the remaining hours to be used for sleeping.

Another reason is that trying to sleep during daylight hours is going against the body’s natural cycle: daytime is when body temperature rises, and levels of melatonin, a hormone that helps maintain circadian rhythm, fall, both of which are known causes of shorter, and more disrupted sleep.

The National Sleep Foundation offers these tips for those with trouble sleeping:

Respect your sleeping space: does your bedroom look more like a NASA control centre or a sanctuary devoted to shielding you from the stresses of everyday life?

Make your sleeping environment comfortable: invest in a good mattress and pillows, remove all distractions.

Keep your bedroom dark for the whole sleeping time: use light-blocking curtains or shades.

Avoid being in bright light late at night. Dim the lights as bedtime approaches. If you wake at night and need light, use a night light or dimmed lights.

Stick to a bedtime routine, allowing enough time for winding down and relaxing before climbing into bed.

If you must have a nap during the day, keep it to less than 45 minutes and don’t do it after 3.00 pm.

Make a rule: if you lie awake for more than 20 minutes, get up and do something relaxing and not too demanding, in a dimly lit environment, until you feel sleepy.

Exercise regularly, but avoid doing this close to bedtime if you are having problems sleeping.

Avoid big meals, caffeinated drinks and alcohol near bedtime.

Use ear plugs or a sound conditioner to block out distracting sounds.

Turn off TV and computer screens in the bedroom.

Written by Catharine Paddock PhD