Do men and women’s hands give off different scent profiles? Plus, flossing could help prevent dementia, and more health news

Dogs can sniff out and track someone based on their scent, a trait that has aided scores of criminal investigations.

Laboratory scientists working with human odors report that a new discovery may also further crime solving: They’ve determined that the scents of women and men differ, at least in their palms.

The researchers were able to predict someone’s sex with nearly 97% accuracy using scent compounds from their palms, according to a report published July 5 in the journal PLOS ONE.

This could help law enforcement agents track down criminals, according to researchers led by Kenneth Furton, chief scientific officer at Florida International University.

Record-breaking heat waves are pummeling the United States and the world, causing many to wonder how much of this a body can take and still survive.

The limit is somewhere between 104 and 122 degrees Fahrenheit if you’re sitting perfectly still, according to a small study conducted in the United Kingdom.

Researchers say they are starting to hone in on the high temperatures that begin to overwhelm the human body’s defenses against heat, or what they call the upper critical temperature.

“We find that some individuals, but not others, exhibit an increase in metabolic rate at rest when ambient temperature gets high,” said senior researcher Lewis Halsey, a professor at the University of Roehampton School of Life and Health Sciences in London.

For much of the COVID-19 pandemic, doctors have told patients who get a negative result after taking a rapid antigen test at home to test again 48 hours later.

A new study confirms that’s the right advice.

Whether you have symptoms or not, repeat testing after 48 hours may be required to rule out COVID infection, researchers from the University of Massachusetts Medical School found.

In the meantime, if you think you may be infected or have been exposed to the virus, you should take precautions to not expose others to the virus until getting a second negative test result, researchers said.

That means wearing a mask and social distancing.

Under the surface of your favorite swimming pool, beach and lakes, hazards too small to be seen by the naked eye may await.

And these bacteria, viruses and parasites can turn a refreshing plunge into a nasty infection.

“There’s a variety of microorganisms that can make recreational activities in water less than fun,” said Dr. Stacey Rose, associate professor of infectious diseases at Baylor College of Medicine in Houston. “Microorganisms thrive in every type of water, and infections will impact everyone differently.”

Recreational swimming has been linked to outbreaks of Cryptosporidium, Legionella, norovirus and Giardia.

Pediatric endocrinologist Dr. Erin Okawa works in a wealthy Los Angeles neighborhood and sees many parents worried about their kids’ height.

“I have a clinic in Manhattan Beach, which was apparently settled by ex-volleyball players and ex-soccer players,” she said. “So there are a lot of very tall parents in Manhattan Beach. And I have referral after referral, I see kid after kid there for short stature concerns.”

When speaking with these prospective patients’ parents, Okawa likes to remind them that even if their child seems short in their above-average-height neck of the woods, if they traveled just 30 minutes east to other parts of L.A. such as South Pasadena, Artesia or San Marino, their son or daughter might even have above-average stature compared to the general population.

Pregnancy triggers many changes to the body, but there’s one that may surprise many women.

A hidden change is that the heart has to pump, on average, nearly 50% more blood by the end of pregnancy than it did before pregnancy, and then it has to quickly go back to “normal operations” after delivery. While most pregnant women’s hearts tolerate these changes well, pregnancy can serve as a “stress test” on the heart that can cause new heart disease in patients who have not had heart problems previously, and can make existing heart issues more difficult to manage.

The most common heart conditions seen in pregnancy are related to high blood pressure conditions in pregnancy (preeclampsia and gestational hypertension), irregular heart rhythms (arrhythmias), and the heart muscle not squeezing strongly enough (heart failure)

Add risk of developing memory problems later in life to the list of consequences linked to poor oral health.

Not taking care of your mouth and teeth has already been associated with heart disease, diabetes, certain cancers and preterm birth. Now, a new study finds that folks with gum disease or tooth loss have evidence of shrinkage within the hippocampus, a brain area essential for memory.

“Retaining more healthy teeth without periodontal disease may help to protect brain health,” said study author Dr. Satoshi Yamaguchi, an associate professor at Tohoku University Graduate School of Dentistry in Sendai, Japan.

The new study was not designed to say how, or even if, the number of healthy teeth or gum disease status causes dementia or memory problems, but previous research suggests that simmering inflammation may be a smoking gun.