If we told you there was a way to burn more calories—in this case, a whopping 500 in just one workout—boost fat loss, enhance muscle gains and improve your cardiovascular fitness without having to endure another long-winded weight-training and treadmill session, you might grab your phone and dial the consumer fraud hotline. But this is one of those rare occasions when the idiom “it seems too good to be true,” would fall on deaf ears. And if you’re looking to take your fitness and fat-loss efforts to the next level without spending more time in the gym, you’ll want to add some of these high-intensity activities to your already-solid foundation.

1. Tabata Time

The Tabata protocol is an extremely high-intensity training method that produces results very quickly. A Tabata workout or sequence is an interval training cycle of 20 seconds of exercise performed at maximum intensity followed by 10 seconds of rest, repeated eight times for a total of four minutes.

The Burning Edge: A study conducted at the National Institute of Fitness and Sports (Japan) found that subjects who performed Tabata five days a week for six weeks improved their maximum aerobic capacities (a measure of the highest amount of oxygen consumed during maximal exercise) by 14 percent and anaerobic capacities (a measure of maximum output over a short period) by 28 percent.

In a nutshell, the extremely short rest periods of Tabata force your body to move between energy systems, producing vast amounts of lactic acid and growth hormone that push your body into accelerated fat-burning mode for hours postworkout.

Burn 500 in: 26 minutes

Tip: To reach your goal of burning 500 calories, perform four separate Tabata intervals, each four minutes in length. Include a five-minute warm-up and cool-down.

2. Cardio Boxing

“The usual cardio-boxing workout consists of a 10-minute warm-up and boxing training techniques — including shadowboxing, punching target mitts, and hitting the heavy bag and speed bag — combined with cardio and muscle-conditioning methods,” says Andy Dumas, a Canada-based certified boxing coach, fitness consultant, author and TV personality. “The main difference is there’s no actual sparring with an opponent.” Like most workouts, every class starts with a solid warm-up. The rest of the hour-long session consists of intervals that mimic boxing rounds: three minutes of intense training followed by roughly 60 seconds of rest.

The Burning Edge: Cardio boxing is rated as one of the best forms of exercise because it conditions the whole body, and builds strength, endurance, balance, agility and coordination at the same time. According to Dumas, however, it’s the weight-loss benefits that top the list for regular attendees. “Jumping rope is one of the best ways to burn calories,” he says. “Some studies show you can burn up to 200 calories skipping rope in just 15 minutes. Most cardio-boxing classes include interval training, and various jump-rope exercises between rounds on the heavy bag and target mitts.”

Burn 500 in: 39 minutes

Tip: “The best instructors are certified in not only fitness but also boxing,” Dumas says. “It’s important for beginners to learn proper punching technique and a good instructor can help teach that.”