Taking a week off from nearly all mental and physical activity - including television, talking on the phone and visiting with friends - was linked with improved mental performance and fewer symptoms in people who had suffered a concussion, a study said.
A week of total rest still had benefits even months after the injury, according to a report in the Journal of Pediatrics.
"That's really important because very often we see patients with post-concussion syndrome months after" their injury, said Rosemarie Moser, director of the Sports Concussion Center of New Jersey and lead author of the study.
Post-concussion syndrome involves headaches, mental fogginess, fatigue and difficulty concentrating or sleeping, among other symptoms.
Typically, rest is the main treatment, Moser said, but it's not systematic or comprehensive and varies according to how the different practitioners define rest. The study aimed to test the results of intensive rest.
Moser's group ordered 49 high school- and college-age patients to rest for a full week. The prescription was strict: they could not go to school or work, talk on the phone, exercise, watch TV, socialize or work at a computer.
Fourteen of the patients started the rest within a week of their injuries. Another 22 patients began resting within a month of the concussion, and 13 patients began the week of rest between one and seven months after the concussion.
At the beginning of the study, all of the patients had concussion-related symptoms, such as headaches and trouble concentrating - but all saw improvement after the week of rest.
Athletes who began the rest within a week of their concussion saw their symptoms fall from a score of 22 on a 132-point scale, to seven. Those who began their rest more than a month out saw symptoms drop from 28 to 8.
"All of those symptoms improved dramatically. Qualitatively, you feel better," Moser said.
Moser's group also had participants take mental tests - measuring memory, processing speed and reaction time - before and after they rested, and found that patients did better on all the mental exams after the rest.
The researchers did not compare the participants' improvement to other people with concussions who got no special rest period, or who got some rest but less than the total rest that they prescribed.
The study "provides some evidence to back up a recommendation that's already out there," said Willem Meeuwisse, a professor at the University of Calgary and a physician specializing in sports injuries who was not part of the study.
But he said it was not clear if the rest needs to be as intensive as it was in the study to provide benefits.