Dear Doctor: My kids say you’re not supposed to admit it, but I hate to exercise. Running a mile once or twice a week is really the most I can manage. Should I even bother?

Dear Reader: In a word, yes. While it would be great if you enjoyed exercising enough to do more of it more often, intriguing new research suggests that when it comes to physical activity, every little bit helps. In fact, a study conducted on mice at the University of Texas Southwestern Medical Center in Dallas found that just one workout kept the nerve cells in the brain that play a role in metabolism activated for up to two days. The takeaway of that research, which was published in December, is that these neurons respond to even a small amount of activity.

The study focused on two types of neurons, which are part of a brain circuit found in humans as well as in mice. These two neuron types, when activated, have very different jobs. One plays a role in lowering glucose levels, muting appetite and revving up the metabolism. The other neuron type does pretty much the opposite -- it ramps up appetite and puts the brakes on metabolism.

Researchers found that a single vigorous workout amplified the activity of the first neuron type -- that’s the one that reduces appetite, lowers glucose and causes energy output to increase -- for up to two days. At the same time, it suppressed the effects of the second neuron type -- the one associated with an increase in hunger and a downshift in metabolic rate -- for the same amount of time. While this is good news for people like you who prefer a more modest exercise schedule, the study also contained an incentive to be even more active: It turns out that these changes to neural activity lasted even longer in people who exercised more often.

Speaking of frequency, would you be willing to take on just 10 to 15 minutes of exercise per day? Although exercise classes and gym sessions are typically measured in hours, emerging research is showing that short bouts of exercise -- as long as they are done daily -- can yield rewards. A study conducted at Pennington Biomedical Research Center in Louisiana found that sedentary women who walked briskly for just 72 minutes per week -- that’s about 10 minutes each day -- had similar improvement to heart strength and general fitness as did the group that walked almost twice as long.

Another study found that as long as it included at least 60 seconds of high-intensity exercise, a 10-minute workout yielded similar benefits to 45 minutes of steady jogging. And for those who take the long view, numerous studies have associated regular exercise with a lower risk of early death.

When it comes to building on your current level of activity, are there any sports or games you enjoyed in the past and would consider doing again? It doesn’t have to be the same thing every day. Even a 10-minute game of tag with your kids a few times a week will get you moving. Think creatively, and we’re sure you’ll land on a solution. And in the meantime, please do keep running.

(Send your questions to askthedoctors@mednet.ucla.edu, or write: Ask the Doctors, c/o UCLA Health Sciences Media Relations, 10880 Wilshire Blvd., Suite 1450, Los Angeles, CA, 90024. Owing to the volume of mail, personal replies cannot be provided.)

Dear Doctor: I heard that getting more potassium will help with high blood pressure. Is that really true? I love salty food, and I really don’t want to give up my chips and popcorn.

Dear Reader: The conversation about blood pressure focuses far more on salt -- or the sodium it contains -- than it does on potassium. That’s because salt is so readily available. It’s a potent flavor enhancer that finds its way into virtually all processed and prepared foods. This makes it easy to blow the daily sodium budget without adding even a grain of it yourself.

The maximum recommended amount of sodium for healthy adults is 2,300 milligrams per day. For certain groups, such as those with hypertension, diabetes, heart disease, chronic kidney disease and adults 51 or older, the maximum drops to no more than 1,500 milligrams per day. In reality, our average daily sodium intake is a whopping 3,746 milligrams per day.

Potassium recommendations are similarly ignored. The most recent research shows the average American adult consumes about 2,000 milligrams of potassium per day. That’s less than half the recommended 4,700 milligrams per day. The result is most of us are not getting the ratio of potassium to sodium that the dietary guidelines recommend, which is twice as much potassium as sodium. In fact, studies show that sodium consumption often significantly outpaces potassium in the American diet.

This imbalance is a problem because sodium and potassium are inextricably linked. To understand why, we need to nerd out a bit. Potassium and sodium are electrolytes, which means they carry a tiny electrical charge. Our cells use this to create a molecular pump. When the pump brings potassium into a cell and pushes sodium out, it creates a kind of chemical battery. The output of these batteries plays a role in nerve function and muscle health, including the heart. Sodium and potassium are also vital to kidney function and bone health, and to blood and fluid balance, which helps regulate blood pressure.

When we overdo it with sodium, our bodies compensate by getting rid of it in urine. But this starts a cascade of events that lead to a loss of potassium and an influx of water, which results in a net increase in blood volume. Not only does that adversely affect blood pressure, the lack of potassium can cause electrical signals in the body to get disrupted. That interferes with the proper functioning of nerves and muscles, including the heart.

By following current United States dietary guidelines, we achieve the potassium-to-sodium ratio mentioned earlier, which is 2-to-1. Newer research leans toward ratios of 5-to-1 and higher. Unfortunately, most Americans miss even the more modest target by wide margins. Not only is that bad news for the vital functions we just discussed, but a new study published earlier this year also found that adults who took in more sodium than potassium increased their risk of stroke by 47 percent.

We understand your love of salt, but it’s quite possible it has put you into potassium debt. Our advice is that not only should you make adding potassium-rich foods to your diet a priority, you should also reduce sodium. For a useful list of potassium-rich foods, visit health.gov/dietaryguidelines/dga2005/document/pdf/Appendix_B.pdf.

(Send your questions to askthedoctors@mednet.ucla.edu, or write: Ask the Doctors, c/o UCLA Health Sciences Media Relations, 10880 Wilshire Blvd., Suite 1450, Los Angeles, CA, 90024. Owing to the volume of mail, personal replies cannot be provided.)

Dear Doctor: I started smoking when I was 25 and stopped when I was 40. I‘m 56 now, and because I was a heavy smoker, I’m really worried about the damage I may have done. Do you think I can get scanned just to be sure everything is OK? Would my insurance pay for it?

Dear Reader: You are not alone in seeking reassurance about the effects of your former smoking habit. Both the federal government and private insurers agree that in cases like yours, lung cancer screenings may be useful.

Research published in the New England Journal of Medicine in 2011 found that when current and former heavy smokers underwent low-dose CT scans, which are a type of X-ray, to screen for cancer and for suspicious changes to lung tissues, a significant number of cancers were caught at an early stage. Researchers reported that the outcome of these screenings was a 20 percent reduction in lung cancer deaths among the population studied. That led to the current recommendation that adults between the ages of 55 and 80 who have smoked 30 packs of cigarettes per year within the last 15 years should undergo a scan. This recommendation covers current smokers and those who have quit within the last 15 years.

Lung cancer is the leading cause of cancer death in the United States, with smoking contributing to up to 90 percent of those deaths among both men and women. According to the American Lung Association, women who smoke are 13 times more likely than nonsmokers to go on to develop lung cancer. Among men, that likelihood goes up to 23 times the rate of nonsmokers. When people who don’t smoke are regularly exposed to secondhand smoke either at home or at work, their risk of developing lung cancer rises 20 to 30 percent. And as long as we’re on the topic, cigarette smoking accounts for about 20 percent of all deaths from heart disease in the U.S. All of which is leading us to our ongoing plea in these columns -- if you’re a smoker, please stop. If you’re not, please don’t be tempted to start.

When it comes to the lung cancer screening recommendations, though, it’s important to note that it’s actually a complex issue. On the plus side is the fact that cancers caught early are easier to treat. However, screening includes the risk of a false-positive result. That’s when a test seems to identify disease when no disease is present. Also of concern is something known as over-diagnosis, which is the discovery of cancer that would not have caused problems to the patient. Each of these can lead to unnecessary procedures and treatment. That’s why screenings are recommended only for heavy smokers and only within a set time frame.

For those who do get a positive result from a screening, it’s important to talk to your health care team about follow-up screenings. Our recommendation is to talk all of this over with your family doctor before you make any decisions regarding a lung cancer screening.

(Send your questions to askthedoctors@mednet.ucla.edu, or write: Ask the Doctors, c/o UCLA Health Sciences Media Relations, 10880 Wilshire Blvd., Suite 1450, Los Angeles, CA, 90024. Owing to the volume of mail, personal replies cannot be provided.)