Dear Doctors: I just turned 57, and my doctor is now saying that I should get vaccinated for pneumonia. The only time I ever had pneumonia was one time when I had a bad case of the flu. Why isn’t he talking about a flu vaccine? I would like to understand the thinking here.

Dear Reader: Let’s begin by discussing pneumonia, which is a kind of respiratory illness. It occurs when the millions of tiny air sacs located deep within the lungs become inflamed. Known as alveoli, the proper functioning of these air sacs is crucial to our health and well-being. The membrane of these air sacs is where the oxygen that you have inhaled gets delivered into the bloodstream. It is also where carbon dioxide, which is a waste product, gets offloaded in order to be exhaled.

When someone has pneumonia, it means that inflammation in the alveoli in one or both lungs has caused a buildup of fluid or pus. This impedes or even prevents the oxygen/carbon dioxide exchange and causes symptoms that can range from mild to severe.

The severity of someone’s illness depends on the microbe that is causing it, their general health and their age. Symptoms can include fever, chills, wheezing, a persistent cough, difficulty breathing, muscle pain (often in the upper back), fatigue or exhaustion. When someone with pneumonia has a cough, mucus may be produced.

Pneumonia can be caused by a virus, bacteria or fungus. Each of these can cause an immune reaction in the tissues of the lungs. Your case of pneumonia, which occurred while you had the flu, is known as viral pneumonia. Fungi can also cause pneumonia, particularly in people who are living with weakened immune systems.

However, your doctor is concerned with a different cause of the condition, which is a bacterial infection. Many types of bacteria can cause pneumonia. The most common here in the United States is Streptococcus pneumoniae, which is also known as pneumococcus bacteria. It is this bacterium that is the target of the vaccine that your doctor is recommending.

As we mentioned, age plays a role in how sick someone gets when they have pneumonia. Older adults and young children are at particular risk for severe disease. For older adults, this is due to multiple factors. One is that immune response tends to become less robust as we reach older age. Older adults are also more likely to be living with other health conditions, such as cardiovascular disease, respiratory disease and Type 2 diabetes. Muscle weakness and frailty can make it difficult to cough and clear the airways. The fatigue and weakness caused by the decrease in blood oxygen during pneumonia can have an adverse effect on cognition.

Due to rising rates of pneumococcal pneumonia, the Centers for Disease Control and Prevention recently lowered the recommended age for the pneumonia vaccine from 65 to 50. The shot also protects against other infections pneumococcus bacteria can cause, including sinus, ear and blood infections, and meningitis. At 57, you are covered by the updated recommendation for a pneumonia vaccine.

(Send your questions to askthedoctors@mednet.ucla.edu, or write: Ask the Doctors, c/o UCLA Health Sciences Media Relations, 10960 Wilshire Blvd., Suite 1955, Los Angeles, CA, 90024. Owing to the volume of mail, personal replies cannot be provided.)

Dear Doctors: I’ve read that people who gain weight during the holidays often don’t manage to lose it again. Is that right? In the last few years, it has happened to me. I have several Christmas parties on my calendar, and I am looking for tips on how not to gain weight but still have fun.

Dear Reader: Yes, the data show that many people gain a bit of weight each year during the holidays. Considering the season of indulgence spans two months, from the sugar rush of Halloween to the soothing comfort foods of New Year’s Day, it’s not that hard to understand why.

What may come as a surprise is that the typical weight gain isn’t that large, ranging from 1/2 to 2 pounds. The problem is that, for many people, the higher post-holiday weight becomes the new normal. As the years go by, those extra pounds add up -- sometimes to a significant weight gain.

The good news is that by planning ahead, it is possible to indulge a bit during the holidays and still avoid adding extra pounds. This was borne out in an interesting study in which researchers in England compared the outcomes of two groups of adults.

One group was taught specific strategies for the holiday eating season. These included what and how to eat at parties, learning to calculate the amount of exercise needed to burn off any extra calories, and closely tracking their weight throughout the season to stay on target.

The other group learned the same general information, but when it came to the party season, they played it by ear. At the start of the new year, the plan-ahead group had maintained their normal weight, while the freelance eaters had put on a few extra pounds.

So what’s the plan? First, don’t go to a party hungry. A small, high-protein snack beforehand takes the edge off of appetite. Once at the gathering, eat in a specific order. Make it an ironclad rule that before you can have any simple carbohydrates, such as sweets, chips, crackers or breads, you first have to have several servings of vegetables. That means the crudite platter is your friend. Follow this with a serving of lean protein.

By the time you’re cleared for the dessert or snack table, both your palate and your appetite will be primed to limit empty calories. And when you get there, don’t eat randomly. Instead, stick with the treats you truly crave.

When it comes to beverages, take the same approach. Start with sparkling water, and then stick to just one caloric or alcoholic drink.

Exercise was another cornerstone of the British study. When participants broke the caloric barrier, they countered with an equal amount of activity. A slice of pie equaled 20 minutes of running, while a small glass of wine meant a half-hour of brisk walking.

The participants were also asked to weigh themselves regularly, which allowed them to immediately take steps to manage the weight gain. We urge you to borrow liberally from these strategies. You’ll have an enjoyable holiday season and emerge with minimal weight gain.

(Send your questions to askthedoctors@mednet.ucla.edu, or write: Ask the Doctors, c/o UCLA Health Sciences Media Relations, 10960 Wilshire Blvd., Suite 1955, Los Angeles, CA, 90024. Owing to the volume of mail, personal replies cannot be provided.)

Dear Doctors: I’m a 68-year-old man who cannot remember the last time I awoke in the morning feeling fully rested. My friends laugh and say those days are long gone for people our age. Is this true? I have decent sleep habits in that I’m in bed reading by 9 p.m. and the lights are out by 11 p.m.

Dear Reader: Bring up the topic of sleep struggles at any gathering, and you are likely to start a lively conversation. It is estimated that up to 70 million adults in the United States are failing to get good-quality sleep, many of them on a regular basis. Problems include trouble falling asleep, difficulty staying asleep, lack of deep sleep and the misery of full-on insomnia. This widespread deficit of good-quality sleep is a significant factor in why more than 40% of adults of all ages report nodding off at some point during the day.

Problems with sleep are divided into two main categories. One is sleep deprivation, which is not getting enough sleep. Your question falls into the other, more complex category, which is sleep deficiency. This is when someone doesn’t spend enough time in the phases of sleep. These are light sleep, REM sleep -- which is the rapid eye-movement phase in which we dream -- and deep sleep. Also known as slow-wave sleep, this is the stage of sleep that leaves you feeling rested and refreshed when you wake up. It’s also the one many older adults struggle with.

As we reach older age, slow-wave becomes more difficult to sustain. One factor is hormonal changes that occur, such as a decrease in testosterone production. The hormone testosterone plays an important role in regulating other hormones, such as cortisol and melatonin, which in turn oversee the body’s circadian -- and thus sleep -- cycles. Older adults also begin to process caffeine more slowly. That means the 2 p.m. coffee that previously didn’t affect nighttime rest now may contribute to sleep deficiency. Additional factors include being in pain, the side effects of certain medications and cognitive changes occurring in the brain.

An important consideration is interrupted sleep. This can occur due to outside stimuli such as light, sound, a restless bedmate, the need to get up to use the bathroom during the night and the morning alarm. When it is the latter, and if you are awoken while in the slow-wave cycle of deep sleep, it can take hours to shake the feeling of grogginess. Another piece is that as we age, the circadian cycles that oversee our sleep needs appear to reset to an earlier time. Some people find an earlier bedtime and an earlier wake-up conducive to better sleep.

That brings us to the issue of artificial light. In our modern, brightly lit lives, the visual cues of waning daylight and growing darkness are largely absent. These trigger the circadian cycles that manage the onset of sleep, which is why it’s so important to avoid the blue light of electronic devices for several hours before bed. And when possible, opt for softer, lower lighting in the hours between sunset and bedtime.

(Send your questions to askthedoctors@mednet.ucla.edu, or write: Ask the Doctors, c/o UCLA Health Sciences Media Relations, 10960 Wilshire Blvd., Suite 1955, Los Angeles, CA, 90024. Owing to the volume of mail, personal replies cannot be provided.)