Looking for a way to reduce heart disease risk or improve brain function? Exercise is the answer, according to two recent studies that add to the list of exercise's health benefits, showing that workouts are good for improving more than just physiques.

Last month, a study showed that aerobic exercise might be the best way to reduce the risk of heart disease, but a new study from the Harvard University School of Public Health says that even 150 minutes of moderate exercise per week can reduce the risk of heart disease by almost 15 percent.

The benefits increased as the amount of exercise increased; 300 minutes per week reduced their risk by 20 percent, and 750 minutes of moderate activity made participants 25 percent less likely to suffer from heart disease. But researchers noted that the benefits were greater for people who had done little exercise and increased slightly than for people who already exercised a lot and increased their exercise time.

"The biggest bang for your buck is at the lower ends of physical activity," says lead study author Jacob Sattelmair. "If you went from none to 2.5 hours a week, the relative benefit is more than if you went from, say, 5 to 7.5 hours a week."

In the study published in this month's Circulation journal, researchers reviewed the findings of 33 studies examining the benefits of exercise. Their analysis revealed a few other interesting points. Women in the studies tended to benefit more from exercise than men, and any physical activity helped improve health, supporting the 2008 Physical Activity Guidelines for Americans' statement that some activity is better than none.

Another study further extols the benefits of exercise, specifically its ability to prevent brain infection and memory loss. Researchers at the University of Colorado found that small amounts of exercise can prevent memory loss after an illness or disease by preventing infection. Ruth Barrientons, lead researcher, says that this is because exercise increases growth factors and aids in memory formation.

The study focused on rats, so the results are not necessarily conclusive for humans, but the findings could be particularly useful as a non-invasive way to help people recovering from illnesses. The positive results researchers saw on older rats' health also suggests that older adults can benefit from even moderate physical activity, which is encouraging to those who might be hesitant to work out due to years of inactivity or age.