Dear Doctor: I played a pretty rough game of tennis a few weeks ago and developed an ache in my right elbow that turned out to be bursitis. What can I do to ease the pain?

Dear Reader: Our skeletons are marvels of mechanical engineering. They create a scaffold for our muscles, skin and circulatory system, shelter our inner organs, and provide the leverage that makes it possible for us to move about. Wherever our bones meet, particularly in our joints, tiny fluid-filled sacs known as bursa act as cushions. They allow bones and connective tissue to glide easily over one another with minimal friction.

When injury, repetitive movement or sustained pressure causes one or more bursa to become inflamed, the resulting pain and tenderness are characteristic of a condition known as bursitis. Age can play a role in bursitis, as can rheumatoid arthritis. The pain arises when an injured bursa fills with excess fluid and then presses against surrounding tissues and nerves.

The most common locations for bursitis are the hip, knee, shoulder and, as you have discovered, the elbow. The condition is diagnosed via a physical examination of the area, and tests such as an X-ray or an MRI. When a physician suspects that infection may play a role in bursitis, she or he will take some fluid from the affected area for testing.

Since we're not sure what treatment you may have already received, we'll run down our approach with our patients. We begin by addressing the underlying cause, which is inflammation. Rest is important. Bursitis can be brought on by a specific activity, such as tennis for bursitis in the elbow, or throwing a ball or lifting a toddler for bursitis in the shoulder. We recommend that our patients refrain from the particular action until the condition has cleared up.

Anti-inflammatory medications such as aspirin and ibuprofen will help alleviate swelling and pain. If necessary, more powerful anti-inflammatories are available by prescription. Ice compresses applied for 15 to 20 minutes every four to six hours, for three to five days, can also be quite effective in managing the swelling and pain.

Less frequently, it becomes necessary to drain the excess fluid from the bursa with a needle and syringe, a procedure known as aspiration. If we suspect infection rather than injury plays a role, we will send the fluid out for analysis.

In many cases, bursitis will resolve itself over the course of a few weeks or, perhaps, months. In some instances, though, the pain may be persistent. When patients don't get relief from rest, icing and anti-inflammatories, the next step can be a cortisone injection into the site. Cortisone usually provides speedy relief from pain and can be targeted to a specific location.

We have found that gradually adding a gentle stretching program and some easy strengthening exercises can aid recovery. An elbow band, which reduces the pressure of the muscles in the forearm, can help with pain. Your family doctor will be able to help you with all of these.

(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: Some studies suggest that long-term calorie restriction can lengthen lifespan; others say it won't. Which should we believe?

Dear Reader: This is a perplexing question. We need energy to live, and the food we eat provides that energy. Obviously, gluttony can lead to dire health consequences, including Type 2 diabetes, obesity and high blood pressure, but less obvious is the case for decreasing caloric intake to below normal levels in order to improve health.

The benefit of calorie restriction was first seen in laboratory rats in the 1930s. Subsequent studies have shown that a 30 to 60 percent reduction in calories in mice and rats led to an increase in both the average and maximal lifespan of the rodents.

Of note, researchers found equal improvement in average lifespan among rodents that exercised to keep the weight down, but no improvement in maximal lifespan. In other words, if the maximal age of a rat is 2 1/2 years, the maximum age would increase to 3 years by calorie restriction, but would stay at 2 1/2 years by exercise.

Calorie restriction has shown benefits in chickens, spiders and even single-celled organisms.

The reason may lie in the reduction of the metabolic rate that occurs with calorie restriction. In reducing the metabolic rate, the body temperature decreases, as does the formation rate of damaging oxidative chemicals. These oxidative chemicals damage DNA, cell membranes and the protein within cells, and may be one of the reasons that bodies age. Also, calorie restriction leads to a decrease in blood sugar and body insulin levels.

As for whether the physical benefits of calorie restriction apply to humans, a 2016 study in non-obese males and females compared those who maintained their normal diets to those who had a 25 percent decrease in their caloric intake. The subjects were followed for 24 months. The calorie restriction group lost almost 16 pounds more than the control group. Further, people's moods improved significantly in the calorie restriction group, as did reported improvements in quality of life, sleep and sexual function.

When it comes to calorie restriction and longevity, note that in Okinawa, Japan, calorie intake is 17 percent less in adults and 36 percent less in children when compared to the rest of Japan. The rate of death from heart attacks, strokes and cancer is 31 to 41 percent less than the national average. This doesn't prove cause and effect, but it does suggest the need for additional research.

Clearly, calorie restriction seems to have benefits, but proving those benefits over the long term in our not-so-steady human lives? That's not easy. Certainly, however, in our world of plenty, we need to be mindful of the amounts that we eat.

(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: I'm about to turn 60, and when I spend the afternoon playing with my 7- and 9-year-old grandsons, I'm wiped out. Is there anything that I can do to feel and be more energetic? I want to be an active grandmother and not just sit on the sidelines.

Dear Reader: We'd like to begin by reassuring you -- it's the rare adult who can match the activity level of a young child, who is basically a marvel of perpetual motion. However, your question does address certain realities of older adulthood.

As we age, particularly when we reach our 60s and beyond, certain changes begin to take place in our bodies. We experience a decrease in muscle mass, which results in a loss of both strength and balance. A change to sleep patterns, including less deep sleep and more frequent awakenings during the night, can cause fatigue, a drop in mental sharpness and even lead to depression. Add in the various other changes that take place in the aging heart and brain, and the result is often a feeling of low energy.

Lifestyle plays a role as well. For many adults, older age or retirement means less daily contact with a variety of people, less decision-making, a lower level of physical activity and even less time spent outdoors.

As you suspected, there are some simple steps you can take to feel better.

-- Eating a diet based on lean proteins, healthful fats, a variety of high-fiber fruits and vegetables, and limited added sugars.

-- Drink enough water. It's easy to forget to stay adequately hydrated. (And no, diet and caffeinated beverages don't count. In fact, they can act as diuretics and result in net fluid loss.)

-- No smoking. Not only does smoking tobacco quite dramatically cut down on your lung capacity, it is a risk factor in heart disease and many cancers.

-- Get enough vitamin D, which is essential to bone health and helps with depression. Spending time in sunlight or taking a supplement are necessary for adequate vitamin D.

-- Make daily exercise a priority. Walking is an excellent way to get your blood flowing and your muscles moving. It takes no equipment, is low-stress, and can be done with a partner or in a group. Yoga is a great for both the body and the mind. Weight-bearing exercises are also important to muscle and bone strength, and to stability.

-- Avoid constipation. Diet, exercise and adequate water will put you on the path to regularity. If you find you're still having trouble, the occasional use of a fiber supplement and a stool softener can be helpful.

-- Be creative about getting enough sleep. Daytime naps can make a big difference. If napping isn't in your skill set, simply taking the time to lie down with your eyes closed for five or 10 minutes can leave you refreshed.

Taken as a whole, these changes to your daily routine can help you feel more energetic -- and help you to keep up with your grandsons.

(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.)