There comes a time in every runner’s life when it’s time to kick things up a notch. That means one thing and one thing only: interval training. There’s a reason loads of runners don’t like intervals.

Eight weeks of HIIT increases both the number and efficiency of muscle mitochondria by expanding their energy-producing inner membranes.

Researchers from the University of Southern Denmark investigated how eight weeks of high-intensity interval training affect the structure of mitochondria—the parts of muscle cells that produce energy.

Here’s a graph showing the fraction of workout time spent at above 90 percent of max heart rate (black bars) and above 90 ...

A tool that can make run/walking even more effective, especially for athletes ready to get faster? The treadmill. Pairing ...

Interval House of Hamilton, an organization that supports women and children who have been victims of abuse, is one of 18 groups across Canada selected to receive a combined $2 million for ...

People often start exercising to lose weight, but the results aren’t always obvious right away. Exercise alone doesn’t guarantee progress. Real change comes when exercise promotes fat burning and ...

Julia Sullivan is a health and fitness writer, editor and content strategist well as a certified personal trainer. Her byline is in many publications from Harper's Bazaar to SELF Magazine to brand ...

The BBC Breakfast host’s PT shares how short workouts power her busy schedule ...

For competitive swimmers and triathletes, the biggest hurdle to consistent training is often access to a dedicated lap pool.

It might be quicker than you'd think.