"We're in love with HIIT workouts because you get a cardio and toning sesh that raises your heart rate while strengthening your muscles," says Dawn. "You get the perks of cardio and the after-burn ...

The founders of Tone It Up share tips for staying fit during the busy holiday season—plus, 3 workout moves you can do anywhere for a holiday HIIT workout. Photo: Getty Images/Artem Varnitsin and EyeEm ...

Here's a quick and intense cardio workout that will spike your heart rate and build muscle. It'll only take you 30 minutes or less, and it's varied enough that it'll also keep you (and your muscles) ...

Tone It Up is known for its fun and challenging at-home workouts that inspire women all over the world to feel fit, strong, and confident. The newest program on its app, The Best by Jasmine Sanders, ...

Karena Dawn and Katrina Scott, cocreators of the fitness community Tone It Up, met — where else? — at the gym on a Friday night in Manhattan Beach, CA. "We were both new to the area and really needed ...

Jillian Michaels and Tone It Up's Karena and Katrina also share their best tips for staying fit during the holidays Fitness gurus Jillian Michaels and Tone It Up’s Karena Dawn and Katrina Scott are ...

We’re taking a peek inside our favorite health and fitness experts’ gym bags to uncover their must-have gear and favorite products. My workout: My favorite workout is a bike ride along the beach, a ...