Dr. Kevin Wright conducted a small research at the sleep and Chronobiology Laboratory in the University of Colorado at Boulder. He said that mental skills performed immediately after getting up in the morning gives compromised results. He also explains that this is due to the fact that the brain is still not alert and the initial waking moments might resemble as if you have been intoxicated. This is called sleep inertia or grogginess. This is the time taken by the brain to become active after the sleep time.
The study included eight men and one woman and their average age was about 29 years old. They were not suffering from any sleep disorder and were asked to refrain from alcohol, medications, nicotine, recreational drugs, and caffeine for the study period. For a period of three weeks they were asked to get eight hours of sleep at home. For the next week the subjects were asked to spend their nights (eight hours of sleep) in the lab.
In the daytime the subjects were given math problems like simple double-digit additions to solve.
After this the patients were woken up in the morning after eight hours of sleep and given math problems immediately. The math test was given to them within moments of waking. Subjects found it very difficult and their performance was really bad. The performance improved and was close to normalcy only after 20 minutes.
Again the subjects were kept occupied for 26 hours and then were given a math test to solve. The results were much better when compared to the results obtained when the subjects were asked to do math test immediately after they got up from bed.
The researcher say that the brain requires a few minutes before it start to work at the normal pace.
But some people, like doctors, soldiers, and emergency workers, have to be on their feet in a moment's notice. Hence it was concluded that such people could not afford to have a lazy prefrontal cortex. The math test challenged short-term memory, counting skills, and speedy thinking. The prefrontal cortex handles all these activities.
The good news is that sleep inertia does not last for more than 3 minutes. But further studies have to be done to prove the delayed effect of sleep inertia. This study helps us to understand about sleep inertia and that our brain needs some time to get started after a long rest.