On the website Canadian Running:
Does 60 seconds of sprints beat 50 minutes of moderate exercise?
One Canadian-led study finds that 10 minutes of exercise including just 60 seconds of sprints beats 50 minutes of moderate continuous exercise for health and fitness gains.
Update: Just received an e-mail from an author of this post: 35 amazing health benefits of running (+10 tips for beginners). It is over 7,000 words and packed with practical tips and advice.