FRIDAY, July 4 (HealthDay News) -- The brains of people who suffer from anxiety and severe shyness may respond more strongly to stress and show signs of being anxious even in situations considered safe by others, say researchers at the University of Wisconsin School of Medicine and Public Health.

They studied brain activity, anxious behavior and stress hormones in adolescent rhesus monkeys. Those with the most anxious temperaments showed higher activity in a part of the brain called the amygdala, which regulates emotion and triggers reactions to anxiety.

FRIDAY, July 4 (HealthDay News) -- Fireworks can be breathtaking spectacles, creating glittering showers of sparks and earth-rumbling booms that thrill people for miles around.

Backyard fireworks can produce their own thrills, but mainly for young boys who love to blow stuff up. And therein lies the danger.

THURSDAY, July 3 (HealthDay News) -- Doing mental or physical work while exhausted may harm your health, a new study shows.

Researchers at the University of Alabama at Birmingham found that fatigued people had bigger spikes in blood pressure than well-rested people while doing a memorization test.

LUBBOCK, Texas - A slice of cool, fresh watermelon is a juicy way to top off a Fourth of July cookout and one that researchers say has effects similar to Viagra — but don't necessarily expect it to keep the fireworks all night long.

Watermelons contain an ingredient called citrulline that can trigger production of a compound that helps relax the body's blood vessels, similar to what happens when a man takes Viagra, said scientists in Texas, one of the nation's top producers of the seedless variety.

WEDNESDAY, July 2 (HealthDay News) -- Drugs designed to control type 2 diabetes should be subjected to more thorough safety reviews to ensure they don't raise the risk of heart problems, U.S. Food and Drug Administration advisers said Wednesday.

The panel of outside experts voted 14-to-2, at the end of a two-day meeting, to recommend that all makers of these drugs conduct long-term cardiovascular trials, even if the drugs show no signs of heart problems in initial trials.

WEDNESDAY, July 2 (HealthDay News) -- Glaucoma doesn't necessarily have to end in blindness, two new studies suggest.

In one report, researchers say they found traditional surgery for glaucoma has better outcomes than using glaucoma drainage devices. The second report found that even patients with end-stage glaucoma can be successfully treated. Both studies were published in the July issue of Ophthalmology.

In the first report, researchers looked at the number of complications from traditional glaucoma surgery versus complications from inserting a device that drains fluid from the eye.

Sexual needs and desires evolve as much as women themselves, but change is not always bad.

Whether women are 30 or 60 years old, if they have a desire to rekindle a sexual romance founder of Women’s Sexual Health Foundation Lisa Martinez says go for it.

Reaching 60 years old was once looked upon as over the hill. However, with a combination of communication and desire, couples can enjoy sex at any age.

As Martinez say, “The first step is to rekindle the relationship.” She says scheduling a date night to solely talk and get to know one another again is highly important.

WEDNESDAY, July 2 (HealthDay News) -- Smokeless tobacco products (STPs), which include products such as snuff and chew tobacco, do increase the user's risk of cancer -- just not as much as smoking does.

So say researchers who examined worldwide patterns of STP use and the associated risk of cancer.

Reporting in the July issue of The Lancet Oncology, a team led by Dr. Paolo Boffeta, of the International Agency for Research on Cancer, in France, noted that STPs contain more than 30 carcinogens, including nitrosamines and metals.

WEDNESDAY, July 2 (HealthDay News) -- Researchers say they've taken a significant stride forward in understanding how relaxation techniques such as meditation, prayer and yoga improve health: by changing patterns of gene activity that affect how the body responds to stress.

The changes were seen both in long-term practitioners and in newer recruits, the scientists said.

TUESDAY, July 1 (HealthDay News) -- As the temperatures rise, older adults become more vulnerable to heat-related health issues because their bodies don't cool down as quickly as younger people.

"Sometimes, older people may not feel hot when the temperature is dangerously high and are also less likely to feel thirsty, which means their bodies have lost too much water," Dr. John B. Murphy, president of The American Geriatrics Society, said in a prepared statement.