God, Hope & Helping Others
January 10, 2014
By Dr. Mercola
One of the key health benefits of exercise is that it helps normalize your glucose, insulin, and leptin levels by optimizing insulin and leptin receptor sensitivity. This is perhaps the most important factor for optimizing your overall health and preventing chronic disease, and may explain why exercise is such a potent preventive medicine.
In fact, researchers recently suggested that exercise is "the best preventive drug" for many common ailments, from psychiatric disorders to heart disease, diabetes, and cancer.1 According to Jordan Metzl, a sports-medicine physician at New York City's Hospital for Special Surgery and author of The Exercise Cure:
"Exercise is the best preventive drug we have, and everybody needs to take that medicine."
And, as stated by Dr. Timothy Church,2 director of preventive medicine research at the Pennington Biomedical Research Center in Baton Rouge:
"Exercise strengthens the entire human machine — the heart, the brain, the blood vessels, the bones, the muscles. The most important thing you can do for your long-term health is lead an active life."
Unfortunately, many fail to get sufficient amounts of exercise. Worse yet, a majority of people may still endanger their health simply by sitting too much. Compelling evidence actually suggests that even if you exercise regularly, prolonged sitting is itself a risk factor for chronic disease and reduced lifespan...
Overall, federal data suggest only 21 percent of American adults meet the government recommendation to engage in two and half hours' worth of aerobic and muscle-strengthening exercise each week, so there's clearly a lot of room for improvement. Ideally though, you'll want to exercise regularly AND frequently interrupt your sitting in order to optimize your health and longevity. I'll review the reasons for this below.
A recent meta-review conducted by researchers at Harvard and Stanford3compared the effectiveness of exercise versus drug interventions on mortality outcomes for diabetes, coronary heart disease, heart failure, and stroke. After reviewing 305 randomized controlled trials, which included nearly 339,300 people, they found "no statistically detectable differences" between physical activity and medications for prediabetes and heart disease.
This is a potent reminder of the power of simple lifestyle changes, as well as the shortcomings of the drug paradigm!
Besides optimizing insulin/leptin receptor sensitivity, other beneficial biochemical changes also occur during exercise, including alterations in more than 20 different metabolites involved in fat burning and metabolism, among other things. As stated by Dr. Church, exercise indeed affects your entire body—from head to toe—in beneficial ways. This includes changes in your:
- Muscles, which use glucose and ATP for contraction and movement. Tiny tears in your muscles make them grow bigger and stronger as they heal. Gaining more muscle through resistance exercises has many benefits, from losing excess fat to maintaining healthy bone mass and preventing age-related muscle loss as you age. The intensity of your resistance training can achieve a number of beneficial changes on the molecular, enzymatic, hormonal, and chemical level in your body.
- Lungs. As your muscles call for more oxygen, your breathing rate increases. The higher your VO2 max—your maximum capacity of oxygen use—the fitter you are.
- Heart. Your heart rate increases with physical activity to supply more oxygenated blood to your muscles. The fitter you are, the more efficiently your heart can do this, allowing you to work out longer and harder. Your blood pressure will also decrease as a result of new blood vessels forming.
- Brain. The increased blood flow also benefits your brain, allowing it to almost immediately function better. Exercising regularly also promotes the growth of new brain cells, boosting your capacity for memory and learning. A number of neurotransmitters are also triggered, such as endorphins, serotonin, dopamine, glutamate, and GABA. Some of these are well-known for their role in mood control. Exercise, in fact, is one of the most effective prevention and treatment strategies for depression.
- Joints and Bones. Exercise can place as much as five or six times more than your body weight on them. Weight-bearing exercise is one of the most effective remedies against osteoporosis, as your bones are very porous and soft, and as you get older, your bones can easily become less dense and hence, more brittle -- especially if you are inactive.
I've often equated exercise to a drug from the perspective that they both need to be wisely prescribed in order to optimize your health. Simply doing random exercises for the sake of "exercising" will not achieve the benefits you seek. In fact it could cause serious injury, especially if you engage in strength training with poor form and no coaching. In terms of "dosage," it's important to note the changes in recommendations that have taken place over the past few years. While conventional aerobic exercise was long considered the "gold standard" of a good workout, research has refuted such notions.
Instead, high-intensity interval training (which requires but a fraction of the time compared to conventional cardio) has been shown to be FAR more efficient and effective, compared to longer, slower cardio workouts. In fact, exercises such as long distance running have been shown to be among the worst forms of exercise, in terms of health benefits.
The reason for this is quite simple. High intensity interval training (HIIT) mimics the movements of our hunter-gatherer ancestors, which included short bursts of high-intensity activities, but not long-distance running. This, researchers say, is what your body is hard-wired for. Basically, by exercising in short bursts, followed by periods of recovery, you recreate exactly what your body needs for optimum health. Twice-weekly sessions, which require no more than 20 minutes from start to finish, can help you:
- Lower your body fat
- Improve your muscle tone
- Boost your energy and libido
- Improve athletic speed and performance
- Naturally increase your body's production of human growth hormone (HGH)—a synergistic, foundational biochemical underpinning that promotes health and longevity. Conventional cardio will NOT boost your HGH level
Next, let's address the issue of non-exercise movement. I also like to call this intermittent movement. This is the latest area of physical activity that's gaining a lot of attention, and for good reason. Studies have repeatedly found strong correlations between prolonged sitting or inactivity and reduced life expectancy—even if you exercise regularly!
It appears that temporary vigorous exercise simply cannot compensate for the damage incurred by prolonged daily sitting. For example, a recent analysis4 of 18 studies, found that those who sat for the longest periods of time were twice as likely to have diabetes or heart disease, compared to those who sat the least. An earlier study5 that highlighted much of the recent evidence linking sitting with biomarkers of poor metabolic health, also found that total sitting time correlates with an increased risk of type 2 diabetes, heart disease, and other prevalent chronic health problems—even if you exercise regularly.
The answer, fortunately, is quite simple. You simply need to make sure you move your body more often. Simply standing up from a seated position has been found particularly effective at counteracting the ill effects of sitting. This is something I seek to do every 15 minutes while I am sitting. I set a timer to remind me. When the timer rings I get up and do some simple hamstring or chest stretches for a minute or two. I am testing a variety of different ones and hope to report on them later this year.
Earlier this year, I interviewed Dr. Joan Vernikos,6 former director of NASA's Life Sciences Division and author of Sitting Kills, Moving Heals, on this topic. Her groundbreaking research reveals why standing up is such an effective remedy—it's because when you stand up, your body acts against gravity. Sitting actually simulates a low-gravity type environment for your body, and your body deteriorates at a far more rapid pace in anti-gravity situations... Hence, the remedy is to continuously engage in physical movements, as this increases the forces of gravity on your body.
Simple everyday activities such as housecleaning, cooking, gardening, hanging clothes to dry, bending over to pick up a stray sock, reaching for an item on a high shelf, all fall within the spectrum of movements you would ideally engage in—more or less continuously—from morning until night. To learn more about this important aspect of health, please see this previous article.
In short, one of the keys to optimal health is to remain as active as you can, all day long. Whenever you have a chance to move and stretch your body in the course of going about your day—do it! That said, there's no doubt that an ideal fitness regimen requires a little more effort. Fortunately, you can accomplish the bulk of it through high intensity exercises, which require a minimal time investment—as little as 20 minutes, two to three times a week. As a general rule, I recommend incorporating a wide variety of exercises, including the following:
- Stand Up Every 15 Minutes. While not intuitively obvious, emerging evidence clearly shows that even highly fit people who exceed the expert exercise recommendations are headed for premature death if they sit for long periods of time. My interview with NASA scientist Dr. Joan Vernikos goes into great detail why this is so, and what you can do about it.
- Interval (Anaerobic) Training: This is when you alternate short bursts of high-intensity exercise with gentle recovery periods.
- Strength Training: Rounding out your exercise program with a 1-set strength training routine will ensure that you're really optimizing the possible health benefits of a regular exercise program. You can also "up" the intensity by slowing it down. For more information about using super slow weight training as a form of high intensity interval exercise, please see my interview with Dr. Doug McGuff.
- Core Exercises: Your body has 29 core muscles located mostly in your back, abdomen and pelvis. This group of muscles provides the foundation for movement throughout your entire body, and strengthening them can help protect and support your back, make your spine and body less prone to injury, and help you gain greater balance and stability.
Foundation Training, created by Dr. Eric Goodman, is an integral first step of a larger program he calls "Modern Moveology," which consists of a catalog of exercises. Postural exercises such as those taught in Foundation Training are critical not just for properly supporting your frame during daily activities; they also retrain your body so you can safely perform high-intensity exercises without risking injury. Exercise programs like Pilates and yoga are also great for strengthening your core muscles, as are specific exercises you can learn from a personal trainer.
- Stretching: My favorite type of stretching is active isolated stretches. With Active Isolated Stretching, you hold each stretch for only two seconds, which works with your body's natural physiological makeup to improve circulation and increase the elasticity of muscle joints. This technique also allows your body to repair itself and prepare for daily activity. You can also use devices like the Power Plate to help you stretch.