Beth Skwarecki is Lifehacker’s Senior Health Editor, and holds certifications as a personal trainer and weightlifting coach. She has been writing about health for over 10 years. I first tried the ...

The Norwegian 4x4 workout has been touted as the ultimate longevity-boosting workout, credited for significantly improving aerobic fitness scores over just eight weeks. Popular among runners and ...

I first tried the Norwegian 4x4 workout a year ago, and since then, it has become a staple of my fitness routine. I don't do it every week (some folks do), but it's a workout I keep returning to ...