If you think that going to the gym 3 times a week or walking to work and back everyday or enough significantly reduce your risk of mortality, think again. Many of us spend the majority of the day sitting down at work.
A few hours of exercise a week do not compensate for spending the majority of the day sitting still. It has been shown that it is enough to move 1 minute every half hour spent sitting down in order to combat the negative effects of sitting still.
Keep in mind however, that standing up simply isn’t enough. You need to actually move! Choose the stairs over the elevator, walk to the printer several times a day etc etc. Try to implement as many active phases throughout your day as possible as this is just as important as implementing a regular exercise routine when it comes to reducing your overall mortality risk.
Source 1: Katzmarzyk PT. Physical activity, sedentary behavior, and health: paradigm paralysis or paradigm shift? Diabetes. 2010 Nov;59(11):2717-25.
Source 2: Peddie MC, Bone JL, Rehrer NJ, Skeaff CM, Gray AR, Perry TL. Breaking prolonged sitting reduces postprandial glycemia in healthy, normal-weight adults: a randomized crossover trial. Am J Clin Nutr. 2013 Aug;98(2):358-66.
Source 3: Bailey DP, Locke CD. Breaking up prolonged sitting with light-intensity walking improves postprandial glycemia, but breaking up sitting with standing does not. J Sci Med Sport. 2014 Mar 20. pii: S1440-2440(14)00051-6.