Daytime sleep worse than split sleep, says FMCSA study

| January 28, 2013

Sleeping during the day makes drivers sleepier and causes drivers to get less sleep than a consolidated sleep period at night and a split sleep schedule, according to results from a study released last week by the Federal Motor Carrier Safety Administration.

Gregory Belenky, a medical doctor at the Sleep and Performance Research Center at Washington State University, conducted the study per request from FMCSA, which wanted to answer the question of whether split sleep is just as beneficial as consolidated sleep in regards to truck drivers, their well-being and their ability to operate a vehicle safely.

“The study compared daily sleep split into two periods versus sleep consolidated into a single period to determine the effects of these sleep patterns on total sleep time, performance, subjective state (sleepiness, mood and effort) and biomedical parameters associated with long-term health,” says FMCSA’s research brief.

The study was conducted between Jan. 10, 2010 and May 5, 2011 and tried to simulate a 5-day workweek in which participants slept either a consolidated period between 10 p.m. and 8 a.m., consolidated period between 10 a.m. and 8 p.m. or two five-hour increments  — one from 3 a.m. to 8 a.m. and one from 3 p.m. to 8 p.m.

Participants who slept at night got more overall sleep time (8.4 hours on average), followed by participants who slept the split sleep schedule (7.2 hours). Those who slept during the day got only 6.4 hours of sleep on average.

Click here to see the full results of the study.

  • Bob_Hearns

    Headline is incorrect. Maybe, if you get to sleep when you are tired, you don’t need as much sleep. So, it isn’t worse, it is just less. Did they test driver’s ability? I hate these half-assed studies because someone or some group is going to use this data incorrectly.

  • Bob_Hearns

    They did test performance and found no difference. So, it’s no big deal how you get your sleep.

  • retired

    The people that do the studys have no idea of the real world. A 5 day week. where did that come from other than maybe a bank teller. Sleep when you need it drive when you don’t. Simple as that

  • WLBlueSkies

    This study is a bunch of bunk…literally. Who really gets to spend that much time in the bunk? The main issue is being able to get some needed bunk time (i.e. nap time) during the day AND be able to stop the clock while doing it. I don’t want to be in the bunk between 10am and 8pm. The studies done will never get it right because of the parameters in which they have to use. It’s common sense…come on FMCSA. Get in the real world and just get it done.

  • Craig Vecellio

    This is good. It shows that getting a nap while you wait to load is helpful and drivers should be able keep driving if they have a refreshing break. Although the subjects showed little difference in performance tests, there were differences in blood composition, which demonstrates the build up of fatigue poisons, and general sleepiness. The test shows what we already know: Get the bulk of your sleep at night if you can, with a nap during the day to refresh. Alternately, get the bulk (but not all) of your sleep in the day if you must, and supplement with a nap at night to refresh. In other words, it proves:
    1)”Sleep when you need it drive when you don’t” with a means to quantify that idea.
    2)Unless you want to fall asleep driving, it is a “big deal how you get your sleep.” Daytime sleep affected blood composition and sleepiness. Anyone who has consistently worked a nightshift already knows this. You never fully acclimate.
    3)”If you get to sleep when you are tired” you are more alert and healthier on the inside. The split sleep not only showed no difference in performance, it also showed no difference in blood composition and general sleepiness. Compared to night sleep, it is true that “if you get to sleep when you are tired, you don’t need as much sleep.” However, that statement falls apart when comparing either sleep habit to day sleep, which is not only shorter, but poorer quality. That’s because it’s not natural to be tired in the day and alert at night.

    As of my posting, there are 3 other comments, all complaints in nature.
    All 3 are based only on the summary, not the detailed data. Wake up guys! This test proves what drivers have been saying all along. Don’t dismiss this test JUST because it was done by the FMCSA. It actually shoots a hole in some of their goofy theories that they have used to manipulate our sleep, which actually resulted in more tired driving. Usually, the FMCSA just messes with us, but this study actually backs up what drivers have been saying. Don’t let your usual dissatisfaction with the FMCSA shade your opinion of this study without reading it, unless you want to reinforce the public’s idea that truckers are dumb.

  • Andrea Sitler

    Personally, from experience with myself as a driver and from dispatching drivers; I found that keeping a driver on a schedule just like you would any other worker is the best bet. If the person is use to day sleep; they sleep fine. I don’t care what profession you are in; you can’t rotate shifts and expect the body to just adjust. If trucking would embrace this simple fact, it would be easier and safer for us all.

  • RETMIL97

    I’ve been doing 95% of my driving between 2200 and 1100 for 15 years. A short nap around 0500 helps. They can do all the studies they want, but until they spend a month on the road with me or some other REAL driver, they aren’t conducting an authentic study. More desk jockeys and inside a building sleep study. Five days a week? That should have clued y’all in on the fallicy of the results.

  • charlie

    jesus, when is big gov. gonna get real??? You know anyone cannot sleep when a damn 4k lb fork lift is going in and out your trailer…Are the guys responding to this actually driving trucks??? I rive at night now for one reason, Most you idiots are in bed and i can move on down the road without you killing me…

  • The Rabbyt-Happily retired

    First of all I would like to know how much the FMCSA paid for this Cock and Bull study. More tax $ spent to get answers to back your cause. The key words TRIED TO STIMULATE A 5 DAY WORKWEEK. You cant do that in trucking. If they wanted to do a real study they would take 50 drivers from all types of trucking jobs give them a waiver to run as they needed without current log rules and see how they fair at the end of 90 days. They have the machines to monitor the rest. You cannot stimulate the driving world with Lab rats that never leave town. Another story to make me sick and they say there is a driver shortage. HOW COME? People of the FMCSA HOW COME? And Mr. Doctor did you work over your hours of limit and maybe make some mistakes in your study FMCSA pull his work hours and see if he was out of hours when he did this.

  • Keith

    You must be living in a fantasy world!! Truck driving is a life style that does not have a day or night sleep time. In order to get the job done, one has to drive when he/she is able too. Most drivers can sleep when and where they need too with respect to day or night time sleeping. We have trained our bodies to adjust to the situation. Sleeping with a forklift going in and out of the trailer is not really sleeping; maybe not really taking a very good nap. These studies are bogus “BS” and a major waste of taxpayer money.

  • Keith

    Andrea: I disagree that one cannot get the body to adjust to a rotating shift. While in the military I worked a rotating shift for many years. 4 swings, 4 midnight, 4 day and 3.5 days off, then started all over again. I and thousands of other military members did just fine. Oh yes we would have loved to be on one set shift, but the rotating shifts offered some good time off for seeing the countries where we were stationed. Also, what about cops, firemen, emergency room doctors and nurses and many many other professions that also work rotating shifts?? And cops carry guns!!!! Doctors and nurses use scalpels and drugs to save lives. Why are those professions not being challenged? Answer: Because our industry doesn’t have the balls to stand up and fight!!!

  • Craig Vecellio

    If by ‘trained our bodies to adjust to the situation’ you mean taking drugs to stay awake, as I have heard many drivers tell stories of, then yeah, you could say that. You can’t sleep randomly and get quality sleep.


    “says FMCSA study”

    Oooooh ! Better pay attention to what their study says…..

    They are GOD and we are Shit.

    I could give a hoot what the FMCSA says, or any Government agency for that matter.

    What a joke.

    Smoke and mirrors.

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