That’s right, they found that after three nights of restricted sleep, not even a double latte can help boost alertness and productivity.
In the study, 48 study participants were allowed just five hours of sleep for five nights in a row (according to the Sleep Health Foundation adults should be aiming for 7 to 9 hours a night).
Some participants were given 200 mg of caffeine (a typical flat white usually contains 150-200mg) twice during the day, while the rest received a placebo.
They then performed a series of cognitive tests that found the caffeinated folk performed better on the first and second days, but after the third night, the benefits had all but disappeared.
The only way to recover from sleep deprivation is - surprise surprise - more sleep.