Want a workout that can improve heart health, boost your metabolism and reduce stress in a fraction of the time? Meet high-intensity interval training.

Coleen Rooney does hers in the shower, Jennifer Lopez in her garden, Arnold Schwarzenegger at the gym, with such enthusiasm, ...

Want to burn fat fast? These five treadmill workouts go beyond running, incorporating incline, sprints, and HIIT to maximize calorie burn and metabolism.

Luca Parmitano ...