Dear Doctor: I've been hearing on the news that researchers have discovered that when stress causes a heart attack, it all begins in the brain. How does this work? And is it even possible to control the way our brain responds?

Dear Reader: Before we dive into the details of the intriguing revelations regarding stress and heart health, we'd like to share some soothing news. The same mind-body connection that researchers believe plays a role in heart attack may also offer a measure of protection through techniques like meditation, yoga and mindful relaxation.

Let's start with the known risk factors for cardiovascular disease, which have been front-page news for decades. Obesity, high cholesterol, hypertension, diabetes and smoking -- we doubt any of our readers are surprised by that lineup. And while mental and emotional stress have long been suspected to contribute to heart disease, the exact mechanism has remained a mystery.

Now researchers from Harvard Medical School have identified the part of the brain that plays a significant role in cardiovascular disease. Known as the amygdala, it's a small, almond-shaped area associated with processing emotion. The amygdala receives and interprets input from throughout the brain. When incoming signals point to danger, the amygdala reacts instantly, bypassing conscious choice. It sets the sympathetic nervous system, which regulates the fight-or-flight reflex, into action.

Using imaging techniques to measure brain activity, the researchers could link increased activity in the amygdala to increased production of white blood cells by the bone marrow. This led to inflammation in the arteries, which is a risk factor for heart attack and stroke.

The good news is that by using techniques to reduce the stress response, we not only feel more calm and serene, but the benefits can also extend to cardiovascular health. So be good to your amygdala (and to your heart) and consider some options.

Many workplaces, community centers, university extension programs and senior citizen centers now offer stress-reduction programs. At the very least, they will bring you together with like-minded individuals. Social isolation is associated with increased stress, so simply becoming part of a community with a common goal is a step forward.

Yoga has long been shown to reduce stress and promote physical, emotional and mental well-being. In fact, studies show that individuals who practice yoga regularly have lower levels of certain stress chemicals in their blood than those who don't do yoga. And although many forms of yoga have sprung up over the years -- some of them quite fast-paced and with a mindset that is almost competitive -- we recommend the gentle and measured approach of basic hatha yoga.

Meditation is also quite effective at reducing stress. Again, studies have shown that people who meditate regularly for just as little as 20 minutes per day reduced their blood pressure and reported feeling less stressed than did their non-meditating counterparts.

Tai chi, Pilates and deep breathing are also good for stress reduction. And don't forget the healing power of the natural world. A contemplative walk in the woods or a park will help you leave your worries behind.

(Send your questions to askthedoctors@mednet.ucla.edu, or write: Ask the Doctors, c/o Media Relations, UCLA Health, 924 Westwood Blvd., Suite 350, Los Angeles, CA, 90095. Owing to the volume of mail, personal replies cannot be provided.)

Dear Doctor: One of the schools in my area has been the focus of news reports about a bacterial meningitis case. How contagious is this disease?

Dear Reader: Bacterial meningitis cases in school-age children, adolescents and college students are predominately caused by two different organisms: Streptococcus pneumoniae and Neisseria meningitidis. Streptococcus causes nearly 50 percent of meningitis between the ages of 2 and 18, while people in their teens and college years face an increased risk of meningitis caused by Neisseria meningitidis. In fact, 46 percent of meningitis cases between ages 11 to 17 are due to N. meningitidis.

The Streptococcus pneumoniae bacterium is spread by close contact with people who cough or sneeze. Upon inhalation, the bacteria adhere to the back of the nasal passage in an area called the nasopharynx. Normally, there the bacteria sit, colonizing the nasopharynx without causing any problems. A study of 2,799 Italian children younger than 7 years of age found that 8.6 percent had S. pneumoniae colonizing the nasopharynx; the biggest risk factor for colonization was a sinus infection over the previous three months.

In most people with this colonization, the immune system keeps the bacteria from invading the cells of the body. However, when the immune system is weakened or when the body is fighting a viral infection, such as influenza, the bacteria can then invade the cells. From there, the bacteria can enter the bloodstream and cross through the blood-brain barrier, replicating readily in the cerebrospinal fluid, leading to the symptoms of meningitis.

The Neisseria meningitidis bacterium is passed from one person to another by secretions from coughing or by saliva from kissing. It's also passed easily among people in close contact. Like Streptococcus, Neisseria also settles in the nasopharynx, where the immune system similarly keeps the bacteria from invading into the cells of the body. People can carry the bacteria for several months within their nasopharynx and unwittingly pass it on to others.

In fact, 5 to 10 percent of people in the United States carry this bacteria in the nasopharynx. Military recruits in closed quarters can have carrier rates up to 40 percent. College students in dormitory situations have carrier rates of 14 to 34 percent. If one person develops meningitis from N. meningitidis, other people with whom they are in close contact are at greater risk.

Again, the bacteria that cause meningitis are quite contagious, but a person's general risk of developing the illness is very low. In addition, children and adolescents are vaccinated for three types of bacteria that can lead to meningitis: Streptococcus pneumoniae, Neisseria meningitidis and Haemophilus influenzae type b. These vaccinations have significantly decreased the rates of meningitis, so make sure that your child gets these vaccinations.

Lastly, if your child has been exposed to somebody with meningitis, watch for fever, neck stiffness and lethargy. If he or she begins to exhibit these symptoms, all potential signs of meningitis infection, take him or her to a doctor as soon as possible.

(Send your questions to askthedoctors@mednet.ucla.edu, or write: Ask the Doctors, c/o Media Relations, UCLA Health, 924 Westwood Blvd., Suite 350, Los Angeles, CA, 90095. Owing to the volume of mail, personal replies cannot be provided.)

Dear Doctor: Is it safe to use an insect repellent with DEET on my 5-month-old? Here in Tennessee, we're approaching prime mosquito season, and we want our little boy to be able to play outside without getting all bitten up.

Dear Reader: There's nothing like the thin, high whine of a mosquito to let you know your picnic or hike or nap on the porch is about to be ruined by slapping, itching and scratching. Unfortunately, mosquitoes are also known carriers of serious diseases. West Nile virus and St. Louis encephalitis have been diagnosed in some areas of the United States. The Zika virus, while rare in the United States, is also a mosquito-borne disease.

According to the Centers for Disease Control and Prevention, insect repellents that contain DEET are safe to use on children 2 months old and older. DEET, which is shorthand for (deep breath) N,N-diethyl-meta-toluamide, is the active ingredient in a wide array of insect repellents.

DEET does not kill insects. It works by blocking the sensory mechanisms that tell insects that something delicious is nearby. Instead of detecting the chemical markers we humans emit in our breath and sweat, the bugs smell ... nothing. They pass us by.

There are specific guidelines you should follow when using DEET on a child. The CDC recommends that you never use a product with a concentration of more than 30 percent DEET. The percentage of DEET in a product doesn't make the insect repellent stronger or more potent; what that number measures is the length of time the insect repellent will be effective.

Products with concentrations of 10 percent keep bugs at bay for about two hours. Those with 21 to 25 percent DEET provide between five to eight hours of protection. And, please note -- current recommendations state that children should not have more than one application of DEET per day.

Although some insect repellents with DEET have sunscreen mixed in, it's best to steer clear of those. Sunscreen must be reapplied throughout the day to be effective. However, since kids should only get one application of DEET per day, the mixed product is of limited use. It's best to start with a base layer of sunscreen and then add insect repellent. You can then add more sunscreen throughout the day as needed.

Insect repellent should be applied to exposed skin and to clothing. When using a spray, apply it outdoors and be sure to keep it away from food. Make sure neither you not your child inhales the product.

We find that while a spray works well on clothes, insect repellent wipes are great for precise applications to a child's wriggling body. And never put insect repellent on a child's hands, which so often find their way into mouths and eyes. Once back indoors, wash the treated skin with soap and water. Treated clothes should be washed before wearing again.

One final thought: While repellents are a great tool, give them a boost by keeping kids in long-sleeved pants and shirts when in the buggy great outdoors.

(Send your questions to askthedoctors@mednet.ucla.edu, or write: Ask the Doctors, c/o Media Relations, UCLA Health, 924 Westwood Blvd., Suite 350, Los Angeles, CA, 90095. Owing to the volume of mail, personal replies cannot be provided.)