According to a study published in the American Journal of Preventive Medicine in August 2010, the presence of a light-rail transit system in a city meant people had higher physical activity (due to walking to and from stations) and, as a result, better physical fitness. There's a pretty good argument to go ahead with Ottawa's light-rail transit plan, if we needed another one.
The paper, entitled "The Effect of Light Rail Transit on Body Mass Index and Physical Activity" by John M. MacDonald, Robert J. Stokes, Deborah A. Cohen, Aaron Kofner, and Greg K. Ridgeway, looked at the city of Charlotte, North Carolina, polling citizen before and after the construction of that city's light-rail transit system (the LYNX) concluding that (according to Science Daily):
LRT reduced BMI [body-mass index] by an average of 1.18 kg/m2 compared to non-LRT users in the same area over a 12-18 month follow-up period. This is equivalent to a relative weight loss of 6.45 lbs for a person who is 5'5. LRT users were also 81% less likely to become obese over time.
So, by the time 2019 rolls around and Ottawa has a light-rail transit system in place, we can all look forward to reaping the health benefits resultant therefrom. If we're not all replaced by robots by then, of course.