Most of us wake up in the mornings feeling over-tired and head straight for the nearest coffee shop on the way to work. Starting the day with a warm cup o' Joe brew is common across the world, with the British Coffee Association estimating that over two billion cups of coffee are consumed each day globally.
However, new research suggests that caffeine only helps us stay alert but doesn't undo the effects of a bad night's rest. The researchers at Michigan State University looked at its effectiveness in helping overcome all aspects of sleep deprivation, not just alertness, and it's terrible news for those who use coffee and other caffeinated products to get through the day. You're better off saving the money you'd spend on coffee and grab yourself a sleep aid, such as one of the best diffusers or best mattress toppers.
The study asked 276 participants to complete two base-setting tasks. They were then randomly assigned to either stay up all night in a lab or head home to get some sleep. The following morning, they were given a capsule either containing 200mg of caffeine or a placebo. All participants then completed the same tasks as they had the night before.
To test the effect on different areas of cognition, the researchers used two types of activity; a vigilance task which monitors your sustained attention, and a "placekeeping task" known as UNRAVEL, which monitors your accuracy in completing the task multiple times without skipping or repeating steps.
As you might expect, the group that stayed up all night performed worse on both tasks than they had the previous evening.
Although the researchers also found that caffeine helped overcome sleep-related impairment in the vigilance task, confirming that coffee can help keep you alert, the caffeinated group showed no improvement over their sleep-deprived uncaffeinated counterparts during the UNRAVEL task. This suggests that lack of sleep affects your mental performance separately from your ability to pay attention for sustained periods.
There are certainly benefits to coffee beyond the short benefits of mental alertness: research has found moderate coffee consumption can accelerate your metabolism, contains antioxidants and can give you a small boost of energy before exercise. But ultimately, there's no substitute for a good night's sleep.
Fortunately, if you give up coffee for a week, you might actually find you sleep better anyway. Just keep one of our best water bottles handy instead.
