June 25, 2009
Weekly News UpdateBrain Function Differs for Morning People and Night Owls
Researchers at the University of Alberta in Canada have discovered that there really is a difference between those who describe themselves as "morning people" and those who consider themselves "night owls." Those self-described as "morning people" tend to wake up early and feel most productive in the morning hours. "Night owls," on the other hand, are the opposite—they tend to feel more productive during the night and do not prefer waking up early in the morning.
A total of 18 people participated in the study. After completing a questionnaire about their habits, the study participants were broken into two equal groups—one group of nine consisted of those who considered themselves morning people and the other group of nine was made up of those who considered themselves night owls. In their experiment, the scientists:
- measured how much muscle force could be generated during maximum contractions
- applied electrical stimulation to a nerve in the back of the participant's knee to assess pathways through the spinal cord
- used trans-cranial magnetic stimulation to stimulate brain cells to send a signal to different muscles in the body
The most interesting result from the study was that the scientists discovered that there is a significant difference in brain function between morning people and night owls. For morning people, cortical excitability (also referred to as brain activity and inhibition) was the highest in the morning and decreased throughout the day, while for night owls, cortical excitability increased throughout the day and was highest around 9 p.m.. The researchers also found that morning people and night owls both showed an increase in spinal-cord excitability (which is related to muscle reflex response) throughout the day. A third finding was that night owls did better on the maximum muscle force test, meaning they got stronger throughout the day, while morning people showed no change in their maximum muscle force throughout the day.
The scientists who conducted this research were quite intrigued by the results and have already begun to consider future experiments. The researchers are interested to find out whether it is possible to switch someone from being a morning person to being a night owl, and vice versa, and how long such a switch might take. The scientists are also interested in determining how the results from this study may be applied in terms of work efficiency and performance, especially in relation to those who work very early and very late shifts.
The results of the scientists' research were published in the June edition of the Journal of Biological Rhythms. Scientists who contributed to the research included Dave Collins, Olle Lagerquist, Alex Ley, and Alex Tamm.