Strict rest for a prolonged period in adolescents who suffer a concussion isn't helpful and may be harmful, according to a new study.

Disagreements over whether resting the brain really aids recovery have generated controversy. A study last year found that kids who did less with their brains while recovering from a concussion tended to get over their symptoms faster. But that was a so-called observational study, which is less reliable than the new research, which was done with gold-standard methods.

In the new study, “Contrary to expectations, strict rest for five days immediately after concussion did not help teenagers get better compared to our current advice of one to two days of rest followed by a gradual return to activity,” researcher Dr. Danny G. Thomas told Reuters Health.

“We found that teenagers instructed to rest for five days actually reported more symptoms over the course of the study,” said Thomas, of the department of pediatrics, emergency medicine at the Children's Hospital of Wisconsin in Milwaukee.

“We should be cautious when imposing excessive restrictions of activity following concussion and mindful that the discharge instructions we provide patients may influence their perception of illness,” he added

The mainstay of concussion management is to rest the brain and body until the early symptoms subside, followed by gradual return to activity. Yet the optimal period of rest remains unclear

Typically, 24 to 48 hours of rest is recommended, but many doctors recommend longer periods of rest and some even advise “cocoon therapy,” with several days in complete darkness to rest the brain, Thomas and colleagues write in Pediatrics.

For the new study, they randomly assigned 88 patients, ages 11 to 22, who came to the emergency department with a concussion to follow either five days of strict rest (no work, no school, no physical activity) or one to two days of rest followed by stepwise return to activity.

Compared to resting for just one to two days, resting for five days did not lead to faster improvements in symptoms, balance, or the ability to think clearly, the researchers report.

To the contrary, adolescents assigned to strict rest for five days needed more time for their symptoms to get better, and they had worse symptoms during the first 10 days after their emergency department visit, compared to the group that rested for one to two days.

“The deleterious effects of strict rest may have more to do with emotional distress caused by school and activity restriction,” the investigators say. "Missing school interactions and falling behind academically may contribute to situational depression increasing physical and emotional symptoms."

The authors of a commentary published with the study write that the optimal rest period after concussion may vary, "depending on age, gender, point in the calendar year, initial symptom level, the particular symptoms that predominate, the level of cognitive function, or other variables.”

Doctors must use “the existing evidence, however limited, to develop a plan” for patients, Dr. William Meehan III and Dr. Richard Bachur of The Micheli Center for Sports Injury Prevention in Waltham, Massachusetts, write in their commentary.

They conclude that in light of what's currently known, "a recommendation of reasonable rest for the first few days after a concussion followed by a gradual resumption of cognitive activities seems prudent.”

However, they say the full plan for managing a concussion shouldn't be decided in the emergency department.

Instead, they advise, “a few days of rest followed by prompt follow-up with the pediatrician, sports medicine physician, or other capable provider should be recommended," so that care can be tailored to each individual.