Friday, June 24, 2011

TRAIN TO GAIN : Cardio Brain Strain Does running cause brain damage the way boxing does? by Jerry Brainum

While aerobic exercise tends to be boring and repetitious, at least there are many types to choose from. The main object of any type of aerobic training is to increase your heart rate to a certain level and maintain it at that level for the duration of the session. Most bodybuilders prefer to do nonjarring types of aerobics as a means of preventing joint injuries. Popular forms include treadmill walking, elliptical machines, stair-climbing machines and stationary cycling.

Running or jogging is usually not recommended for bodybuilders because of the excessive and cumulative joint trauma that results. Every time your foot hits the ground—even on a soft surface such as grass—you transmit forces equal to three times your bodyweight to your skeletal structure and joints. Running on a hard surface, such as a concrete sidewalk, increases that force to five times bodyweight. Those who run on streets with heavy traffic compound the damage by breathing poisonous auto emissions, such as carbon monoxide. You’re better off sitting in front of the TV and smoking a cigarette than running under those conditions.

Running may have an even more insidious effect, according to one preliminary study.1 It examined the effects of various activities, including both long- and short-distance running, on a specific brain protein called S-100B that also exists in lesser amounts in fat cells, skin-pigment cells (melanocytes) and the testes. Studies show that a rise in this particular protein in the blood is a harbinger of brain deficits.

The study compared the levels of S-100B released by subjects during a number of activities: amateur competitive boxing and sparring, before and after running a 25-kilometer (15.5-mile) race, jogging for 6.2 miles, interval sprinting for two minutes at top speed three times around a track, high-intensity interval stationary cycling—characterized by high-intensity cycling interspersed with one-minute breaks—and heading, or bouncing a soccer ball off the head 20 times.

Boxing is known to cause brain damage, especially among professional boxers. One need look no further than the great former heavyweight champion Muhammad Ali to see what happens when a pro stays in the ring past his prime. Ali suffers from a form of Parkinsonism, marked by damage to the parts of the brain that produce the neurotransmitter dopamine. Lack of sufficient dopamine produces the stiffness, tremors and slow gait evident in Ali, although it doesn’t affect his intellectual capacity.

Other former boxers wind up with dementia pugilistica, which causes brain damage similar to that of Alzheimer’s disease. Again, that’s due to long-term trauma, like being punched in the head. Many neurologists think that no boxer who stays in the ring long enough escapes such damage, though the extent of it varies. One early sign is a marked slurring of speech.

S-100B is an early indicator that something is amiss in the brain. It increases during acute brain events, such as strokes. In the study reported here, as you might expect, boxers fighting without protective headgear showed the highest levels of S-100B. Only one boxer showed no increase in S-100B, and he was also the only boxer who didn’t get hit. Competitive boxing produced higher S-100B levels than sparring.

Despite that, none of the boxers showed levels of S-100B that would point to incipient brain damage. The true surprise was that S-100B levels were similar in all running activities and sparring. To rule out an exercise effect, the authors looked at S-100B in cyclists who trained hard; they showed no increase in the protein.

So why did runners and boxers engaged in sparring show similar levels of S-100B? The theory is that the jarring from running causes a vibration in the brain, leading to a release of the protein. Interestingly, banging the head with a soccer ball didn’t have the same effect, and a previous study showed that not even bungee jumping produced a rise in S-100B.

The unanswered question is whether regular running, since it does increase S-100B, may lead to a type of brain deficit. On the other hand, the fact that similar levels of the protein occur with sparring and running is a bit sobering. The S-100B levels after jogging for 6.2 miles and sparring were nearly the same. Good reason to stick to nonjarring aerobic exercise.

1 Otto, M., et al. (2000). Boxing and running lead to a rise in serum levels of S-100B protein. Int J Sports Med. 21:551-55.

©,2013 Jerry Brainum. Any reprinting in any type of media, including electronic and foreign is expressly prohibited.

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