vendredi 28 février 2014

Women Need Only Exercise at Moderate Intensity to Protect Against Stroke; Men Need More Vigorous Fitness Plan

February 28, 2014 |  
By Dr. Mercola
The health benefits of exercise cannot be overstated. And while diet accounts for about 80 percent of the health benefits you reap from a healthy lifestyle, exercise works in a synergistic manner with proper nutrition to truly optimize your health.
Exercise benefits such as preventing obesity and diabetes, reducing stress, and lowering your blood pressure are among the most obvious. Maintaining a fitness regimen can also go a long way toward warding off a stroke, as all of these factors also affect your stroke risk.
A stroke involves either a rupture of an artery that feeds your brain (hemorrhagic stroke), or an obstruction of blood flow (ischemic stroke), with the ischemic type representing 75 percent of all strokes.
A mini-stroke, or TIA (transient ischemic attack), is caused by a temporary blockage in your cerebral blood vessels. The symptoms are similar to those of a stroke, but they're typically milder and shorter in duration.
Your risk of stroke increases with age, with most occurring after age 55. However, the rate of strokes among younger people (under age 55) has been on a steady incline over the past decades, with stroke rates nearly doubling between 1993 and 2005.1
Thankfully, up to 80 percent of strokes are preventable. Research2 shows that lifestyle factors such as diet, exercise, weight, blood sugar levels, blood pressure, and smoking can have a direct bearing on your individual risk.

Exercise Lowers Your Stroke Risk

Research  published last year3 found that if you're inactive, you have a 20 percent higher risk for having a stroke or mini-stroke (transient ischemic attack) than people who exercise enough to break a sweat at least four times a week. The connection between vigorous exercise and stroke risk was very clear in men, but interestingly, less clear in women.
Lead researcher Dr. Michelle McDonnell speculated that women may benefit more from less vigorous exercise, such as walking, which this study did not examine.4 More recent research presented at the 2014 American Stroke Association's International Stroke Conference, supports Dr. McDonnell's speculation.
The study found that moderate exercise (such as taking a brisk walk) reduced women's stroke risk by 20 percent. It also helped to mildly offset the increased stroke risk in older women using postmenopausal hormone therapy. As reported by Medical News Today:5
"The researchers, led by Prof. Sophia Wang of the Beckman Research Institute in California, say this decreased risk from moderate exercise is just as strong as that of strenuous exercise...
Prof. Wang says she was surprised that the link to reduced stroke risk was strongest with moderate physical activity. 'More strenuous activity such as running didn't further reduce women's stroke risk,' she adds. 'Moderate activity, such as brisk walking appeared to be ideal in this scenario.'"
Apparent differences between the sexes have repeatedly emerged in studies on exercise benefits. Another 2013 study6 also concluded that walking at least three hours per week reduces stroke risk in women better than high intensity cardio. One possible explanation is that women may be more susceptible to the excessive physical stress "conventional cardio" exerts on the heart.
Men, on the other hand, appear to fare better with higher intensity exercise. For example, one 2009 study published in Neurology7 found that vigorous exercise reduces stroke risk in men, and helps them recover from a stroke better and faster as well.

Moderate to heavy exercise was, again, not found to have a protective effect for women. I would expect the right type of cardio to lower stroke risk in both men and women, but those studies have not yet been done.

Peak Fitness Is Safer and More Effective Than Traditional Cardio

Several recent studies have indicated that conventional cardio, especially endurance exercises such as marathon running, can pose significant risks to your heart. It can result in acute volume overload, inflammation, thickening and stiffening of the heart muscle and arteries, arterial calcification, arrhythmias, and potentially sudden cardiac arrest and stroke—the very things you're trying to avoid by exercising.
I don't think anyone can argue against the fact that vigorous exercise is beneficial to your heart, but conventional cardio is far from ideal, and this just might be why so many studies find women do not reap any major cardiovascular benefits from such exertion.  
Ideally, to get the most benefits from your exercise, you need to push your body hard enough for a challenge while allowing adequate time for recovery and repair to take place. One of the best ways to accomplish this is with HIIT, or high intensity interval training, which consists of short bursts of high-intensity exercise, as opposed to extended episodes of vigorous exertion. This is a core part of my Peak Fitness program.
HIIT maximizes your secretion of human growth hormone (HGH), optimizes your metabolism and helps regulate your insulin and blood sugar. And nothing beats it in terms of efficiency. You can complete an entire Peak Fitness workout in 20 minutes or less. For detailed instructions and a demonstration, please see my previous article, "High Intensity Interval Training 101."

Sunlight Can Also Play an Important Role in Stroke Prevention


Previous research8, 9 has shown that reducing your systolic blood pressure by 20 millimeters (regardless of how high your blood pressure currently is) decreases your risk of stroke by 50 percent. Reduce it by another 20 mm, and you cut your individual risk in half yet again. One way to naturally reduce your blood pressure is through exercise. Another is by making sure you're getting enough sun exposure. Recently published research 10 from Great Britain shows that exposure to sunlight reduces high blood pressure by altering the level of nitric oxide in your skin, which dilates your blood vessels. As reported by CTV News:11
"To conduct the study, the team analyzed 24 volunteers who were exposed to ultraviolet (UVA) light from tanning lamps for two 20-minute sessions... 'Small amounts of NO (nitric oxide) are transferred from the skin to the circulation, lowering blood vessel tone,' said Martin Feelisch, a professor of experimental medicine at the University of Southampton in southern England...  'Avoiding excess sunlight exposure is critical to prevent skin cancer, but not being exposed to it at all, out of fear or as a result of a certain lifestyle, could increase the risk of cardiovascular disease.'"
Of course, exposing your skin to the sun also helps optimize your vitamin D level, and vitamin D deficiency may actually DOUBLE your stroke risk.12 Ideally, you'll want to maintain a vitamin D level of 50-70ng/ml year-round. Interestingly, previous research13 also suggests that inducing nitric oxide (NO) actually helps protect your skin against UV damage.
Another crucial element in the normalization of blood pressure is to address insulin and leptin resistance, which is present in about 80 percent of the population from eating far too many carbohydrates and not getting enough exercise. If you have high blood pressure and are overweight, your first step is to eliminate all grains, sugars and processed foods and increase healthy fats, like avocado, coconut oil, butter, and nuts.

Exercise Outdoors to Maximize Your Benefits

Besides offering cardiovascular protection, nitric oxide also promotes wound healing through its antimicrobial effect, and has some anti-cancer activity. The benefits of NO are yet another reason why getting sun exposure is likely to be FAR better than swallowing vitamin D capsules. Sunlight actually has a wide range of health benefits beyond vitamin D production.
To maximize the benefits from exercise and sunlight, it makes sense to exercise outdoors whenever possible ideally during the middle of the day. This will also help you maintain a natural and proper light rhythm, which will help improve your sleep as well. A recent interview with researcher Dan Pardi addressed this in some detail.
If you want to take it a step further, exercise barefoot. Walking barefoot on the Earth, aka "earthing" or "grounding," makes your blood less prone to "hypercoagulation," meaning less likely to clot, and that too reduces your stroke risk. Research has demonstrated that it takes about 80 minutes for the free electrons from the earth to reach your blood stream and transform your blood, so make it a point to regularly walk barefoot on grass or on wet sand for about 90 minutes to two hours, if possible.

Dietary Considerations

As a general rule, eating unprocessed, natural foods will help to reduce your risk of stroke. As for specific items to avoid, the following are at the top of the list:
  • Trans fats are known to promote inflammation, which is a hallmark of most chronic and/or serious diseases, including strokes and heart disease. Women in particular would be well served to avoid trans fats as stroke rates are on the rise in middle-aged women, and poor dietary choices are likely a significant culprit. In one 2010 study,14 post-menopausal women who consumed the most daily dietary trans fat had a 30 percent higher incidence of ischemic strokes.
  • Certain preservatives, such as sodium nitrate and nitrite found in smoked and processed meats have also been shown to damage your blood vessels, which could increase your risk of stroke.
  • Artificial sweeteners may also increase your risk. Previous research has shown that drinking just one diet soda a day may increase your risk of stroke by 48 percent.

Recognizing a Stroke FAST Could Save Your Life

Considering that about 80 percent of strokes are preventable through lifestyle strategies such as diet, exercise and sun exposure, it sure makes a lot of sense to address those factors before it's too late. That said, if you or someone you love suffers a stroke, getting medical help quickly can mean the different between life and death, or permanent disability. This is an area where conventional medicine excels, as there are emergency medications that can dissolve a blood clot that is blocking blood flow to your brain.
If done quickly enough, emergency medicine can prevent or reverse permanent neurological damage—but you typically need treatment within one hour, which means the faster you recognize the warning signs, the better the prognosis. The National Stroke Association recommends using the FAST acronym to help remember the warning signs of stroke:15
F = FACE: Ask the person to smile. Does one side of the face droop?
A = ARMS: Ask the person to raise both arms. Does one arm drift downward?
S = SPEECH: Ask the person to repeat a simple phrase. Does their speech sound slurred or strange?
T = TIME: If you observe any of these signs, call 9-1-1 immediately.

[-] Sources and References

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