If you want better grades, start exercising more often Words by Igor Mihajlavic, Saurav Acharya and Igor Mihajlovic · 8 years, 1 month ago "I don't care what the activity is, if it is weightlifting, if it is going for a bike ride, a run, a swim, they're all good. But you can't use your phone, you can't use your computer to watch Youtube," said UBC professor Peter Graf.