Several studies on the effects of watching too much TV has been done in the past, but a new research says that young adults may develop an increased risk for Alzheimer's because of this.

For 25 years, researchers from the Northern California Institute for Research and Education in San Francisco kept track of the activities of 3,200 individuals between the ages of 18 to 30 and assessed their TV habits vis-a-vis their physical activities. The researchers found out that 17 percent of the participants in the study exhibited a long-term pattern of low physical activity, while 11 percent were highly exposed to TV watching. Three percent of the participants, meanwhile, exhibited both patterns.

The participants were also asked to take tests to determine memory function, cognitive ability and speed.

In their findings, it was revealed that both types of long-term patterns - sedentary lifestyle or high television viewing - presented individuals who developed problems with their cognitive function later on in life. This, barring other factors like age, race, education, sex, BMI, as well as smoking or alcohol habits.

But for participants have both long-term patterns, their cognitive function was twice as likely to falter as they age.

"Our findings demonstrate that even early and mid-adulthood may be critical periods for promotion of physical activity for healthy cognitive aging," said Tina Hoang, one of the study's authors in a press release.

"Sedentary behaviors, like TV viewing, could be especially relevant for future generations of adults due to the growing use of screen-based technologies. Because research indicates that Alzheimer's and other dementias develop over several decades, increasing physical activity and reducing sedentary behavior beginning in early adulthood may have a significant public health impact," she added.

"What's happening at one's midlife is setting the stage for what's happening over the next 20 or 30 years," said Kristine Yaffe, another study author, via Washington Post.

The researchers, however, said these individuals can still lower their risks with some lifestyle changes. "This is something you can do something about," Yaffe said.

The study defines "high television viewing" as more than four hours of TV-watching daily.

The findings were presented during the Alzheimer's Association International Conference in Washington, D.C. Monday.