A third major category of health impacts concerns the effects that transport planning decisions have on physical activity and fitness.Public health officials are increasingly concerned about declining physical fitness,excessive body weight,and resulting increases in diseases such as diabetes.They recommend that adult average at least 150 weekly minutes(about 22 daily minutes) of monderate-intensity physical activity,and children average about three times that amount.A meta-analysis of 22 cohort studies concluded that,compared with no reported physical activity,2.5 weekly hours of monderate activity is associated with a 19% reduction in mortality and 7 weekly hours is associated with a 24% reduction.