Most people probably don't think that daily activities -- like hanging clothes or picking up groceries -- will have an impact on their long-term health. But new research shows that doing lots of these low-intensity physical activities can reduce the risk of cardiovascular disease.
　　
　　For most people, light physical activity accounts for a large proportion of their daily physical activity. However, government guidelines focus almost exclusively on moderate to high intensity physical activity. The difficulty of measuring a person's low-intensity physical activity explains much of the disconnect. It is almost impossible to measure low - intensity physical activity with a questionnaire. The amount of low-intensity physical activity a person thinks they do bears little resemblance to what they actually do. This means it has been difficult to study the long-term health effects of low levels of physical activity.
　　
　　The new study, published in the Journal JAMA Network Open, succeeded in more accurately measuring low intensity physical activity in nearly 6,000 older women. They found that over the next five years, those who had the most low-intensity exercise a day (six hours or more) were 46 percent less likely to have a heart attack or die from one. Compared with women who had at least three hours of low-intensity activity a day or less, they were 26 percent less likely to have any form of cardiovascular "event" (stroke, severe angina).
　　
　　There is clear evidence of a dose-response relationship: the more time people spend engaged in low-intensity activity, the lower their risk of cardiovascular disease. For each additional hour of low-intensity exercise over three hours, the risk of a heart attack was reduced by 15 percent. Even taking into account levels of high physical activity, low intensity activity seems to be important.
　　
　　Uncover cause and effect?
　　
　　One criticism of the study was that it was cross-sectional and could never prove with certainty the direction of the observed relationships. It is possible that the ability to do a lot of low-intensity activity is a sign of health rather than a cause of it. Therefore, it is important to follow up intervention studies aimed at increasing low intensity physical activity to see if this reduces the risk of cardiovascular disease.
　　
　　Still, some smaller experimental studies have shown that low intensity activity is important for our long-term health. For example, low intensity physical activity is an important component of overall physical activity energy expenditure, which has an impact on regulating body weight and body composition. Regularly breaking up long periods of sitting by engaging in short, low-intensity activities can also significantly lower post-meal blood glucose, insulin and fat levels. Instead, requiring people to limit the low-intensity activities they do leads to aerobic activity and a rapid decline in lean muscle tissue, as well as an increase in body fat, blood sugar, and insulin.
　　
　　Is low intensity activity enough?
　　
　　Does this study mean we should encourage people to focus on increasing the low intensity activities they do? Exercise physiologists don't think so. Low-intensity activities may play a role, but we know that physical activity has many other important aspects as well. For example, only regular moderate physical activity is likely to improve cardiopulmonary health. Moreover, only regular resistance exercises such as weight lifting can maintain or increase muscle mass and strength as we age.
　　
　　The most important component of the body is overall physical activity, including mild, moderate and intense intensity (and fidgeting), as this largely explains the difference in a person's total energy expenditure each day. It is possible for a person to do well in one aspect of physical activity and do poorly in another. Think of the office worker who sits in front of a computer most of the day (toxic) but goes out two nights a week for 30 minutes of moderate-intensity running (beneficial). Some physical activity is good for general health, but the more the better. We need to encourage more physical activity, such as increasing light - and moderate-intensity physical activity and increasing the frequency of physical activity to break the habit of sitting for long periods of time. Then try to get organized two or three times a week to improve your cardiovascular and muscle health.
　　
　　Creating a social, cultural, community and artificial environment that encourages everyone to be more proactive remains one of the major public health challenges of the 21st century.