The benefits to exercising can be immediate. More energy and better sleep are two. While fitness has immediate effects on the body now, fitness as a young adult can also impact the body down the line, particularly where the brain is concerned.
A new study found that highly fit young men were less likely than unfit individuals to develop epilepsy, a brain disorder that causes repeated seizures, later in life. Highly fit young men were also less likely than averagely fit young men to develop epilepsy later on.
According to the study's authors, their findings show how exercise can serve as a preventive measure against epilepsy and delay its progression.
"Include aerobic activities in your workout."
For this study, Jenny Nyberg, PhD, from the Center for Brain Repair and Rehabilitation at the University of Gothenburg in Sweden, led a team of researchers to investigate how exercise and cardiovascular fitness, or heart health, affected young men's chances of developing epilepsy later in life.
The study included data from more than one million Swedish men enrolling in the military who were born between 1950 and 1987.
The researchers gathered data through hospital registers from each participant who had their cardiovascular health assessed on a scale of 1 to 9 during conscription examinations using a bike test. A score of 1 is the lowest level of fitness.
The men also underwent standard physical and psychological exams by psychologists and medical doctors during the conscription exams. Their risk for developing epilepsy was measured during the follow-up period beginning December 2008.
Participants were tracked for up to 40 years with follow-up times averaging about 24 years long. Those who had epileptic seizures and other neurologic disorders before age 18 were excluded from the study.
The researchers further analyzed differences in epilepsy risk among brothers who enrolled in the military.
Over the course of the study, 6,796 cases of epilepsy, or 0.6 percent of the participants, were documented. The researchers found that men who had a low level of cardiovascular fitness at age 18 were almost 79 percent more likely to develop epilepsy in the future than men who were highly fit at age 18.
Men with a medium level of cardiovascular fitness at age 18 were about 36 percent more likely than men who were highly fit at age 18 to develop epilepsy.
Among the participants who developed epilepsy, after conscription, 152 had diabetes, 332 had a severe traumatic brain injury (TBI) and 497 had a cerebrovascular disease.
After excluding participants who were diagnosed with severe TBI, cerebrovascular disease or diabetes before conscription, the researchers still found that participants who had low levels of cardiovascular fitness were still 74 percent more likely than the most fit individuals to be diagnosed with epilepsy.
At the same time, those with medium levels of cardiovascular fitness were 29 percent more likely than the most fit individuals to be diagnosed with epilepsy.
Though the cause behind seizure cases is unknown, the researchers said that the ties between fitness and epilepsy risk later in life could be explained by severe TBIs, tumors, neurodegenerative disorders, brain inflammation and cerebrovascular disease (a group of brain dysfunctions related to the vessels supplying blood to the brain).
Since depression decreases with increased physical fitness, the researchers said that an underlying feature found in both depression and epilepsy could explain why epilepsy risk decreases with exercise.
"Exercise may affect epilepsy risk in two ways," said study co-author Elinor Ben-Menachem, PhD, MD, of the University of Gothenburg, in a press release. "It may protect the brain and create stronger brain reserve, or it may simply be that people who are fit early in life tend to also be fit later in life, which in turn affects disease risk."
The authors of this study believe that cardiovascular fitness at age 18 may contribute to an increased brain reserve capacity, which is a measure of how resilient the brain is to damage or pathological changes. Thus, exercise could be a behavior that lowers the chances of developing epilepsy, they wrote in their report.
The researchers noted they did not know whether patients had histories of hypertension, heart attacks, inflammation or infection in the brain or brain tumors, which could have affected their results.
In addition, the researchers might have underestimated the number of cases of severe TBIs, cerebrovascular disease and diabetes, which were the only conditions analyzed. Other variables need further investigation, according to the researchers.
This study was funded by grants from the Märtha Lundqvists Stiftelse, Wilhelm and Martina Lundgrens Stiftelse, Sten A Olsson Foundation for Research and Culture and the Swedish Research Council for Worklife and Social Science (FAS).
The Swedish Medical Research Council and the Swedish government under the LUA/ALF agreement for biomedical research also funded the study, which was published online September 4 in Neurology, a journal of the American Academy of Neurology.
Three of the authors reported no conflicts of interest. The other authors received research support, institutional support and governmental funding from a couple of foundations and organizations not involved with the study, including Bial, UCB and Eisai.