The bad cold that followed that time you got caught in a rainstorm. Those flu symptoms that seemed to come right on the heels of a flu shot.

Anecdotally, it seems that human experience sometimes flies in the face of research that tells us there are a lot of medical myths out there.

Dr. Chad Braden, a family practice physician, dispelled some of those myths at a recent event for Ochsner Health Center’s Golden Opportunity Program for people age 50 and older.

THE MYTH: Reading in dim light ruins your eyesight.

THE TRUTH: No, it doesn’t, and neither does sitting too close to the TV, Braden said. While both activities can cause eye strain, neither causes any permanent damage, he said.

THE MYTH: The flu shot gives you the flu.

THE TRUTH: The flu shot won’t give you the flu, Braden said, but sometimes, unfortunately, people may pick up the virus from others in the surroundings, when they go in for the shot. With timing like that, the vaccination appears to be the culprit.

THE MYTH: Being out in the cold or rain makes one more likely to get a cold or pneumonia.

THE TRUTH: Being outside in the elements doesn’t cause colds. Actually, being inside, out of the weather, increases the chance of catching a cold, as “people congregate and swap viruses,” Braden said.

THE MYTH: Sugar makes kids hyper.

THE TRUTH: “No good studies have shown that extra sugar affected the behavior of children,” Braden said. Research has shown that when parents think their children have been given a drink containing sugar — even it it’s really sugar-free — they rate their children’s behavior as more hyperactive. “What we think is happening is that the myth is out there, and children and parents believe it,” Braden said.

THE MYTH: Cracking your knuckles causes arthritis.

THE TRUTH: Chronic knuckle-cracking may cause wear and tear of the tendons, but it doesn’t cause the inflammation of the joints that is arthritis, Braden said.

The popping sound is made by the forming of a bubble of carbon dioxide in fluid that’s located inside the joint.

THE MYTH: Shaving hair causes it to grown back faster, darker or coarser.

THE TRUTH: It’s an optical illusion, said Braden. New hair growing back in may catch the light differently. It’s also not long enough to have split ends, which affects the texture of longer hair, and it hasn’t had a chance to be lightened by the sun.

THE MYTH: We only use 10 percent of our brain.

THE TRUTH: Most of us use 100 percent, Braden said.

“Numerous types of brain imaging studies show that no area of the brain is completely silent or inactive,” he said.

THE MYTH: Eating turkey makes you drowsy.

THE TRUTH: The carbohydrate-rich side dishes that often accompany a turkey dinner increase something in the brain called tryptophan, an amino acid. That, in turn leads to the synthesis of the neurotransmitter serotonin, then to the making of the hormone melatonin that brings on that “familiar sleepy feeling” after the holiday meal, Braden said.

THE MYTH: You lose most of your body heat through your head.

THE TRUTH: “There is nothing special about the head and heat loss,” Braden said.

The misconception arose from military studies in the 1930s and 1940s on survival in freezing conditions. Study participants in the Artic wore special survival suits that didn’t let any body heat escape — but they didn’t wear anything on their heads, he said.

Heat is lost from the body indiscriminately, from all over, Braden said.

“It’s all the same,” he said.

THE MYTH: Eating at night makes you fat.

THE TRUTH: That’s only going to happen if it’s your fourth or fifth meal of the day, Braden said.

“Studies have found no link at all between eating at night and weight gain,” he said.

“People gain weight because they take in more calories overall than they burn up,” he said.

THE MYTH: There’s a cure for hangovers brought on by drinking too much alcohol, if only it could be found.

THE TRUTH: “No scientific evidence supports any cure or effective prevention for alcohol hangovers,” Braden said.

The most effective way to avoid a hangover is to consume alcohol only in moderation or not at all, he said.

Braden also said that if you believe each of the following, you’re absolutely right:

There’s no proven benefit in taking a daily vitamin.

Eating too much salt increases blood pressure, and

You don’t need to drink eight glasses of water a day. The amount of water a person needs to stay hydrated during the day, he said, depends on the content of the food they eat, the temperature of the environment and the person’s activity.

People can generally rely on their feeling of thirst and can monitor whether their urine is clear to light yellow, a sign of adequate hydration, he said.

People in their 80s and older, however, are less sensitive to signs of thirst, so caregivers should help them remember to stay hydrated, Braden said.