Candy can hinder athletic performance
Lamar Odom, the star forward for the Los Angeles Lakers, is known for his outsized love of candy, sometimes downing entire bags of chocolate and jelly beans on game day. Recently, a doctor and Lakers fan wrote an essay linking Odom’s sweet tooth to his “erratic”, and sometimes lethargic, play. Odom countered that if anything, the excessive sugar helps his performance.
What do studies have to say?
According to research, candy before exercise can enhance performance, but only to a point. Studies have shown, for example, that when athletes eat a 180-calorie candy bar and then ride a stationary bike for an hour—sprinting for the final 15 minutes—they perform better than on days when they drink only water beforehand. But on days when the subjects eat a solid meal a few hours earlier and then have sugar before riding, they do better than on just the sugar alone.
Candy can be as efficient as healthier options such as fruit, and because people typically secrete little insulin during exercise, crashing is unlikely, says Nancy Clark, a sports nutritionist. But candy lacks nutrients that are critical to bone strength and post-exercise recovery.
For best results, pre-exercise meals should combine protein and easily digestible carbohydrates.
The bottom line
Sugar can work as quick fuel for exercise, but nutrient-rich foods are better.
Weight training is bad for blood pressure
It’s well known that regular aerobic exercise can improve circulation and reduce blood pressure. But what about weightlifting?
For years, people with hypertension were warned against it, because doctors feared that spikes in blood pressure during strenuous lifting might lead to dangerous problems and, in the long term, raise blood pressure. But studies had not provided much evidence. And in recent years, large studies have found the opposite: Ultimately, weightlifting reduces resting blood pressure, because with stronger muscles there is less demand on the heart during everyday activities.
For example, an analysis in the journal Hypertension examined 11 clinical trials, comparing 182 adults who lifted weights several times a week and 138 who did not. Overall, it found that weight training lowered resting systolic blood pressure (the top number in a pressure reading) by 2% and diastolic pressure by about 4%—small gains that can greatly improve cardiovascular health.
Another report by the American Heart Association, published in the journal Circulation, found that just two or three bouts of weight training a week—with exercises such as curls and presses—were enough to lower blood pressure.
The association says resistance training can benefit heart patients as well, but recommends consulting with a doctor first for guidance.
The bottom line
Weight training can actually lower resting blood pressure.
Eye exercises can enhance your vision
For almost a century, eye exercises have been promoted as a way to strengthen vision and ease nearsightedness and astigmatism, much like exercise for the body trims fat and improves health.
Some of the most popular techniques include eye-hand coordination drills, eye-movement routines and focusing on blinking lights. The techniques are widely promoted online and advocated by various companies, some even claiming that they can reduce the need for glasses and ease learning disabilities. But several studies have concluded that many of these do-it-yourself techniques are baseless.
One of the latest studies, published this year, found little evidence in support of vision exercises that supposedly slow or reduce myopia, ease dyslexia and correct conditions caused by physiological problems such as blurred vision. A similar conclusion had been reached in a 2005 report that reviewed 43 previous studies finding “no clear scientific evidence” for most of the methods reviewed.
But there are some areas of vision therapy that have been scientifically validated, including one called orthoptics. In this therapy, eye doctors prescribe exercises that can relieve double vision, focus problems and conditions such as strabismus, also known as crossed eyes. Orthoptics can treat convergence insufficiency, in which the eyes have trouble working together. It affects as many as one in five people, but with the right exercises, it can be all but cured, studies show.
The bottom line
Eye exercises are useful for some problems, but they do not seem to relieve myopia or dyslexia.
©2009/THE NEW YORK TIMES
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