Want to train smarter, not harder? Of course you do. Here's everything you need to know about heart rate training, including HIIT.

Four seconds of intense intervals, repeated until they amount to a minute of total exertion, led to rapid improvements in strength and fitness in middle-aged and older adults.

Although no exercise can target stomach fat, high-intensity interval training can be effective in reducing it and offers some advantages.

Regular exercise helps you live longer, right? And vigorous exercise is particularly good for you, isn't it? A big study of older people, thought to be the first of its kind, has been trying to tease out the answer.

Many inactive adults who tried a sampling of exercises preferred intense efforts to gentler workouts.

Tips to stay fit during the pandemic, even without a coach and gym.

In Part VI of this seven-part series on how to reboot your workout routine, fitness expert Dana Santas shares how to effectively -- and safely -- ramp up your workouts with high-intensity interval training.

Low-intensity activity doesn't prepare you for the big event.

HITT.

We all know the benefits of regular exercise, but will doing vigorous exercise make you fitter faster?

Cardio training doesn't have to be a slog if you master this fitness acronym.

A few minutes of brief, intense exercise may be as effective, or more effective, for incinerating body fat than walking, jogging, swimming or cycling for lengthier periods.

Doing the vacuuming or taking the dog for a walk? Pick up the pace – these bursts of incidental exercise could be key to improving your fitness.

As little as 20 seconds of brisk stair climbing, done several times a day, might be enough to increase aerobic fitness.

Kiwi fitness expert calls for guidelines around high-intensity interval training.

The popular fitness trend sounds brutal. But a simple tool can make it speed by.

Intense treadmill exercise may slow the progression of Parkinson's disease in people recently diagnosed with the condition, a study says.

Old mice could rapidly gain fitness and strength, even if they started off frail and exercised for only a few minutes a week.

What really matters
I don't care about your bench press, squat, deadlift, handstand or best "FRAN". I don't care about how hot your yoga was, how many grams of protein you consume daily during your $500 nutritional cleanse, or how many Instagram followers look at your body each day.  

I only care if you can run, possess strength and stamina, and move with intensity – HIIT bolsters each of those variables, and that's why HIIT isn't a trend but more the root of any workout program.

“No exercise is bad, and some exercise, whatever it is, is better than none,” de Heer says. “Aerobic exercise has all kinds of benefits. Intervals are even better. That’s my summary.”

Several striking new studies provide some clarity by showing that exercise seems able to drastically alter how genes operate, perhaps altering the risk for problems like obesity and diabetes.

Think you’re too busy to work out? We have the workout for you. In minutes, high-intensity interval training (H.I.I.T.) will have you sweating, breathing hard and maximizing the health benefits of exercise without the time commitment. Best of all, it’s scientifically proven to work.