By Dr. Mercola

If one of your goals for 2013 is to get in better shape, congratulations! This is one of the most important steps you can take to protect your health. And while you may think this will automatically require spending more time at the gym, this isn’t necessarily the case, especially if you’ve grown used to hour-long treadmill sessions or grueling long-distance runs.

The most recent, cutting-edge exercise research suggests that not only can you get a phenomenal workout in just 20 minutes or sometimes even less, but the little things – such as making an effort to stand more instead of sitting – also add up.

The Exercise 'Sweet Spot'

In research presented at the 2012 annual meeting of the American College of Sports Medicine in San Francisco, it was revealed, as you might suspect, that regular exercisers (in this case runners) had a 19 percent lower risk of dying from any cause than non-runners.¹

What was interesting, however, was that the people who exercised moderately, running one to 20 miles per week at a pace of about 10-11 minute miles (a jogging rate), had an even lower risk of dying than those who ran more than 20 miles a week or at a pace faster than seven miles per hour.

As the featured New York Times article reported, similar results were also found by Denmark researchers, who revealed that overweight men who exercised moderately for about 30 minutes several times a week for 13 weeks lost more weight than those who worked out double that amount.² The more intense exercisers also ended up sitting around more overall, perhaps because they were so tired from their exercise sessions, the researchers suggested. So more was not necessarily better, and as even more research is bearing out, it appears too much exercise may actually be a health risk.

Too Much Exercise Can Backfire

I've often described exercise as a drug that needs to be taken in the ideal dosage to impart the optimal benefit. Too little, and you won't get any benefit. Too much, and you could do harm. For example, Olympic medalists who engaged in extreme power sports such as weight lifting generally had shorter life expectancies than those engaging in endurance or mixed sports, according to one recent study.³ Likewise, Olympic athletes who engaged in the most extreme contact sports, such as rugby had shorter lifespans than other athletes.⁴

Your body is meant to be active throughout the day, and it's also designed for intense, vigorous activity – although the latter appears best limited to short intervals instead of long, strenuous workouts.

Extreme endurance cardio, such as marathon running, actually damages your heart, and can negate the health benefits you'd otherwise reap from a regular fitness program. Research has shown that once you reach 40-50 minutes of vigorous exercise per day, the benefits from your efforts plateau, and further efforts do not convey further improvements in life expectancy.

Even moderate activity, such as brisk walking, for just 75 minutes a week is associated with an increase in life expectancy of nearly two years,⁵ while staying fit during middle age is also known to help lower your risk of developing at least eight common chronic diseases over the next 2.5 decades.⁶

The key to getting the most benefits is balancing your workouts so that they’re challenging enough to keep you progressing fitness-wise, but not so overly strenuous that they cause harm. Part of finding this balance lies with giving yourself ample time for recovery (the more intense your workout, the greater time you’ll need for recovery).

Short, High-Intensity Interval Training May Help You Reach Your 'Goldilocks Zone'

An accumulating body of clinical research now suggests that the best fitness regimen is actually one that mimics the movements of our hunter-gatherer ancestors, which included short bursts of high-intensity activities, but not long-distance running such as is required to complete a marathon. The idea behind "hunter-gatherer fitness" is to closely emulate the actions that ancient man took on a daily basis. This is what your body is hard-wired for, after all, and includes such attributes as:

• A variety of exercises performed regularly (weight training, cardio, stretching, etc.)
• Alternate difficult days with easier days
• Interval training sessions performed once or twice a week
• Weight training at least twice a week
• Ample time for rest after physical exertion

Your exercise program should be challenging, as it was for our ancestors, but it should not be excessive and it should be paired with ample time for recovery. By exercising in intense, short bursts, followed by periods of recovery, you recreate exactly what your body needs for optimum health, and that includes the production of growth hormones, the burning of excess body fat, and improved cardiovascular health and stamina.

High-intensity interval exercises offer pretty astounding benefits to your heart and risk of chronic diseases, like diabetes, which research showing it can lead to "significant improvements" in both heart and blood vessel functioning,⁷ as well as improvements in blood sugar regulation (and that was after just ONE session)!⁸

A Sample High-Intensity Workout – Just 20 Minutes Long

In the case of high-intensity interval workouts like Peak Fitness exercises, less is more, as you can get all the benefits you need in just a 20-minute session performed twice a week. In fact, you should not do these exercises more than three times a week, as if you do it more frequently than that you may actually do more harm than good, as discussed.

If you are using exercise equipment, I recommend using a recumbent bicycle or an elliptical machine for your high-intensity interval training, although you certainly can use a treadmill, or sprint anywhere outdoors. Just beware that if you sprint outside, you must take care to stretch prior to sprinting. Also, unless you are already an athlete, I would strongly advise against sprinting outdoors, as several people I know became injured doing it the first time that way. For a demonstration using an elliptical machine, please see the video above. Here are the core principles:

• Warm up for three minutes
• Exercise as hard and fast as you can for 30 seconds. You should be gasping for breath and feel like you couldn't possibly go on another few seconds. It is better to use lower resistance and higher repetitions to increase your heart rate
• Recover for 90 seconds, still moving, but at slower pace and decreased resistance
• Repeat the high-intensity exercise and recovery 7 more times. (When you're first starting out, depending on your level of fitness, you may only be able to do two or three repetitions of the high-intensity intervals. As you get fitter, just keep adding repetitions until you're doing eight during your 20-minute session)
• Cool down for a few minutes afterward by cutting down your intensity by 50-80 percent

In addition to doing high-intensity interval exercises a couple of times a week, it's wise to alternate a wide variety of exercises in order to truly optimize your health. Without variety, your body will quickly adapt and the benefits will begin to plateau. Along with high-intensity interval training, I also recommend strength training, core exercises and stretching (especially active isolated stretches).

Get Moving Even in Your 'Off' Time

It’s becoming clear that in order to achieve the highest level of fitness, you need to move your body not only during your designated “exercise” times but also during your leisure and work hours (which make up most of your day).

Recent research estimates that if you cut back on the amount of time spent sitting down to less than three hours a day, it could add two years to the your life expectancy.⁹ So whenever you can, stand, stretch, walk in place, dance or use any other posture than simply sitting down. The more you move your body in any 24-hour period (except obviously when you’re sleeping), the better.

Unfortunately, most people spend a large portion of each day in a seated position. It's hard to avoid these days, as computer work predominates, and most also spend many precious hours each week commuting to and from work. To compensate for long hours spent sitting down at work, you could incorporate Foundation Training exercises, powerful simple structural movements that help strengthen and realign your body posture.