For nurses, drivers and others working the night shift, a cup of caffeine may do more than help them stay awake. According to a new study by Cochrane researchers, it may also help them avoid mistakes and improve their job performance, say researchers. This could mean fewer job-related accidents and injuries, although studies have yet to prove this.
What do we know already?
Everyone has days when they haven't had enough sleep and are tired, unfocused, and unproductive at work. Most people bounce back after a good night's sleep, but on-the-job fatigue can be an ongoing problem for people working the night shift or other irregular hours. This is because their work schedule conflicts with their internal 'body clock', which dictates that they feel sleepy at night (when they're trying to work) and lively during the day (when they're trying to sleep). This can mean that they get few hours of sleep, making them even more tired at night when working.
Doctors have a name for this problem: shift work disorder (SWD). Such chronic sleepiness can lead to work-related accidents and injuries, which can be particularly serious in jobs where precision and safety are paramount, such as health care and transportation.
The best way to relieve shift work disorder is to resume a normal schedule, but for many people this isn't possible. So researchers have looked at other ways to help people cope with their irregular hours. One approach favored by many workers is to consume caffeine-rich beverages and foods, such as coffee, energy drinks, and chocolate.
Researchers have now gathered the best studies on how caffeine affects people whose body clock has been disrupted by either shift work or jet lag (which produces similar effects). They looked at 13 studies in total. In these studies, some people were given drinks, snacks, or tablets with caffeine, while others were given identical items without caffeine.
What does the new study say?
People who were given caffeine were less likely to make errors than those who didn't have caffeine. They also performed better on tests measuring their memory, attention, perception, concept formation, and reasoning. However, there was no difference between the groups in their speaking and language skills.
Some studies also compared caffeine with other treatments used for shift work disorder, such as napping, being exposed to bright light to imitate daylight, and taking a drug called Modafinil. There wasn't much difference among the treatments, although one study found that caffeine helped reduce errors more than napping did. However, there isn't yet enough research to say which treatment works best.
Six studies reported mild side effects among those given caffeine, including sleep problems and headaches.
How reliable are the findings?
This was a thorough review of studies and should provide an accurate snapshot of what is currently known about caffeine's effects on people doing shift work. However, we can't yet be certain about how exactly the caffeine works.
What does this mean for me?
If you work irregular hours, caffeine may help improve your on-the-job alertness and performance, and reduce your risk of making mistakes, although we can't yet be certain. We also don't know how caffeine compares with other treatments for shift work problems, and which treatment might be best.
What should I do now?
If you use caffeinated drinks or snacks to be more alert at work, you have no reason to stop based on this research. Indeed, your caffeine intake may even be boosting your job performance.
However, it is possible to get too much caffeine, which can lead to headaches, restlessness, anxiety, and lost sleep, among other problems. So, as with most things, moderation is best.
And if you're routinely tired and not getting enough sleep, you might need to see your doctor. Besides causing problems at work, long-term sleep difficulties can increase your risk of serious health issues, such as obesity, diabetes, and heart problems.