# Why we should exercise - and why we don't - Harvard Health Source URL:: https://www.health.harvard.edu/newsletter_article/why-we-should-exercise-and-why-we-dont It's easy to find reasons not to exercise, but it's also relatively easy to meet the recommended guidelines for physical activity. Here are 27 suggestions for ways to be more physically act... ## Highlights > [!quote]+ %%Updated on Thu Sep 14 2023 10:22:22 GMT-0400%% > > Clearly some of us are less athletic than others — and some unathletic individuals were simply born that way. Twin studies suggest that about half of the difference in physical activity among people is probably inherited. And researchers are making headway in identifying particular genes that may influence how we respond to physical exertion. For example, they've identified some of the genes responsible for variation in the beta-agonist receptors in the lungs. How your lungs and heart react to strenuous exercise depends, in part, on those receptors.