2015-12-18

By Dr. Mercola

Do you want to exercise but think you don't have the time? First, let go of your self-limiting belief. You do have time to exercise; virtually everyone does. But, you have to make it a priority.

There are many excuses you could make to skip your workout. Perhaps you're tired, working late, or feel guilty spending the time on you. But, there are few activities that will give you a bigger return on your investment than breaking a good sweat.

Exercise reduces your risk of chronic diseases such as heart disease, cancer, diabetes, and more, while offering mental health benefits (like a lowered risk of depression) as well. But you probably knew that already.

Did you know, however, that exercise is so potent researchers have suggested drug companies ought to be required to include it for comparison when conducting clinical trials for new drugs?1 It's true, and here's another bit of good news.

Gone are the days when going to the gym needs to take you two hours. In fact, you don't even have to go to the gym at all if you don't want to. Some of the best workouts can be done in 20 minutes or less, right in your own living room.

What Makes Short, High-Intensity Workouts so Effective?

Contrary to popular belief, extended extreme cardio, such as marathon running, actually sets in motion inflammatory mechanisms that damage your heart.

So, while your heart is indeed designed to work very hard, and will be strengthened from doing so, it's only designed to do so intermittently, and for short periods — not for an hour or more at a time. This is the natural body mechanics you tap into when you perform high-intensity interval training (HIIT).

HIIT workouts have been shown to burn more calories than traditional workouts and burn more body fat in less time.2

According to the American College of Sports Medicine, HIIT workouts tend to burn anywhere from 6 to 15 percent more calories compared to other workouts, thanks to the calories you burn after you exercise.3

One study published in the Journal of Obesity4 reported that 12 weeks of HIIT not only can result in significant reductions in total abdominal, trunk, and visceral fat, but also can give you significant increases in fat-free mass and aerobic power.

Aside from burning body fat, HIIT also provides health benefits you simply cannot get from regular aerobics, such as a tremendous boost in human growth hormone (HGH), aka the "fitness hormone."

Yet another study found that unfit but otherwise healthy middle-aged adults were able to improve their insulin sensitivity and blood sugar regulation, after just two weeks of interval training (three sessions per week).5

A follow-up study also found that interval training positively impacted insulin sensitivity. In fact, the study involved people with full-blown type 2 diabetes, and just ONE interval training session was able to improve blood sugar regulation for the next 24 hours!6

How Top Trainers Exercise When They Have Only 15 Minutes

Several top trainers shared their go-to 15-minute fitness routines with Greatist.7 If you're short on time but still want to reap all the benefits exercise has to offer, try one of these quick workouts.

1. 3 Bodyweight Moves to Build Strength

Benjamin Wegman, trainer at The Fhitting Room in New York City

"In 10 minutes, complete 20 reps of each move below and as many rounds of the circuit as possible.

Push-Up

Sit-Up

Squat

For the last five minutes, complete 10 burpees every minute on the minute. In other words, perform 10 burpees in 60 seconds, resting for any remaining time in the minute. At the start of the next minute, perform 10 burpees again."

2. 5 Rounds of 5 Moves to Spike Your Heart Rate

Adam Rosante, NYC-based trainer, founder of The People's Bootcamp and author of "The 30-Second Body"

"Perform each move for 30 seconds. At the end of all five moves, rest for 30 seconds. You'll complete the entire circuit five times in 15 minutes

Jump Squat

Push-Up

Lunge

Mountain Climber

Forearm Plank"

3. The Countdown Workout

Astrid Swan, celebrity trainer based in Los Angeles

"Start by performing 10 reps of each exercise, then do nine, then eight, etc., until you perform one rep of each exercise, and you're done.

Burpee to Box Jump

Lateral Shuffle

Jump Lunge

Push-Up"

4. The Ultimate Stair Workout

Rob Sulaver, founder of Bandana Training

"Spend three minutes warming up your calves, quads, and glutes with exercises of your choice. Sprint up five flights of stairs. Walk back down. Repeat for 10 rounds (or as much as you can do in 15 minutes)."

5. The Quick Gym Workout

Tim Hartwig, L.A.-based trainer who has worked with Sloan Stephens and Antonio Brown

"You'll need: A kettlebell and a rowing machine. Complete as many rounds as possible of the circuit below in 15 minutes.

500-meter Row (aim for a time of 1:40 or faster)

15 Kettlebell Swing

60 seconds rest"

6. A Total-Body Dumbbell Workout

Brett Hoebel, former trainer on NBC's The Biggest Loser and creator of The 20 Minute Body

"You'll need: A set of dumbbells. Perform each move for 60 seconds. After completing all three moves, rest for 60 seconds. Repeat the circuit four times.

Squat-to-Overhead Press (with dumbbells)

Renegade Row (with dumbbells)

Sit-Ups"

Build Muscle and Burn Fat With This 12-Minute High-Intensity Workout

Don't have 20 minutes to spare? You can still fit in a quick workout like the one that follows. Developed by Farouk Houssein, another trainer from The Fhitting Room in New York City, it's a full-body workout in just 12 minutes. He told Yahoo Health:8

"This workout is efficient and to the point. Anyone who is pressed for time or limited on equipment can do this … These dynamic exercises combined with the high-intensity design of the workout will build lean muscle and blast fat long after your workout is complete."

The workout is actually two parts. The first part includes Dr. Izumi Tabata's HIIT protocol. There are many methods of HIIT, and Dr. Tabata's HIIT protocol calls for just 20 seconds of all-out drop-dead effort, followed by a mere 10 seconds of rest. This intense cycle is repeated eight times.

After monitoring the Japanese speed skating team in the early '90s, Dr. Tabata noticed that extremely hard but intermittent exercise appeared to be at least as effective as standard workouts that require several hours a week. The training protocol he came up with as a result requires a mere four minutes, four times a week. Such short workouts can work as long as the intensity is high enough.9

The 12-minute workout that follows consists of a "2-minute interval session and an 8-minute circuit challenge. Rest two minutes after the intervals before going on to part two of the workout."10

Part 1: 4-Minute Tabata Burn

"… [D]o 20 seconds of max effort followed by 10 seconds of rest, and repeat this eight times (four minutes total). Alternate between the two exercises below each round."11

Tuckups: "Start on the ground, balancing yourself on only your butt and hugging your knees. Then, simultaneously extend the legs and arms out. Bring your knees and arms in to return to the starting position. That's one rep."

Burpees: "Begin standing with feet shoulder-width apart. Bend at the knees and hips to lower your body into a squat, then place your hands on the floor in front of your body. Then, kick your feet back so that you are in pushup position. Lower your chest to the floor. Then reverse the movement: Press up to finish the pushup, kick your feet into a squat, and stand up. Complete the move by jumping into the air with arms overhead. All of that is one rep."

Part 2: Full-Body Challenge

For the full-body challenge, set a timer for eight minutes. Do eight reps of each exercise below, which counts as one round. Repeat as many rounds as you can before the timer runs out, resting as needed. Keep track of how many rounds you complete so you can track your progress and try to beat it next time.

1. Dumbbell Thrusters

"Perform this exercise as one continuous movement. To begin, hold a pair of dumbbells at your shoulders, with palms in and elbows facing forward. Then, bend at your hips and knees to lower your body into a squat. Now, rapidly stand up while pressing the dumbbells overhead. (It's OK to use the momentum of your body to help press the dumbbells.) Return the weights to your shoulders, and repeat the steps."

2. Renegade Row with Pushup

"Grasp a set of dumbbells, palms in. Set up in a plank position: dumbbells and your toes on the floor, arms straight, with your body forming a straight line from head to toe. Keeping your body in a straight line, pull one dumbbell up to your chest, squeezing your upper back at the top of the movement. Return to the plank position. Row the dumbbell on your other side, then perform a pushup. All of that is one rep."

3. Jumping Alternating Lunges

"Begin standing with feet shoulder-width apart. Take a big step forward and lower the body until the back knee gently touches the ground. Keep your shin vertical, and don't let the front knee pass your toes. Jump both feet off the ground simultaneously and switch leading legs in the air. Land in the same position, but with the other leg in front. That's one rep."

Want to Try a 7-Minute Workout?

If you don't have 15 minutes, and you don't have 12 minutes, how about seven minutes? That's all it takes to perform the 7-minute workout. An article in the American College of Sports Medicine's Health & Fitness Journal explained how you can fulfill the requirements for a high-intensity exercise session using nothing more than your own body weight, a chair, a wall and a mere seven minutes of your time.12

The program calls for as little as 10 to 15 seconds of rest between each 30-second exercise, which should be performed in rapid succession. One of the added boons of this 7-minute program is that since you don't need any equipment, you can easily take this routine with you when traveling.

You'd be hard-pressed to find a hotel room that doesn't at least have a chair in it. When done at the appropriate intensity, which should hover around 8 on a scale of 1-10, the following 12 exercises, which are outlined in the report, equate to doing a long run and a weight-training session. The exercises are ideally done in the following order, as this allows for opposing muscle groups to alternate between resting and working in each subsequent exercise.



Research has shown that as little as three minutes of HIIT per week for four weeks can improve your insulin sensitivity by 24 percent. You can also experiment with some plyometrics, super sets, interval cardio, and other workout shortcuts.

Bodyweight exercises have the advantage of being very flexible and convenient, requiring no equipment or special place or schedule, and the price is right—they're free! Mountain climbers, burpees, and countless variations of push-ups, pull-ups, and squats are some of the hardest bodyweight exercises you'll find, but you can weave them into even the busiest of days.

Finally, remember that even though you need only a relatively short period of high-intensity activity each week, this doesn't mean you should spend the rest of your time sedentary. The more active you stay during your non-exercise hours the better.

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