Dear Doctor: How common are night sweats in men, and what causes them? I tease my husband that he’s having sympathy hot flashes, but he’s not amused. The sweats usually happen between 3 a.m. and 6 a.m. Neither his primary care physician nor cardiologist have an answer.

Dear Reader: It’s true that because night sweats are associated with hormonal shifts during menopause, they are often seen as an issue that affects women. However, as your husband knows firsthand, they can happen to people of any sex. Unlike occasional bouts of nighttime perspiration, which can arise when the bed or the bedroom are too warm, or when you’re ill and have a fever, night sweats are defined as repeated episodes of extreme sweating. Even when the room they are sleeping in is cool, someone with night sweats will awaken to find themselves, their pajamas and even their bedding drenched in perspiration.

Sweating is a cooling mechanisms that helps to maintain the narrow temperature range the body’s physical and chemical processes require for optimal function. When your body signals that your core temperature is rising, a small area of the brain known as the hypothalamus sends out an alert. It activates certain sweat glands, which secrete a clear, odorless fluid, composed mostly of water, that evaporates and cools the body. How much you sweat typically depends on temperature and humidity, and on physical exertion, which generates internal heat. Stress, fear and other emotions can also have an impact on sweating. So can alcohol, spicy foods and certain medications and medical treatments.

When heavy sweating becomes chronic, it’s called hyperhidrosis. When it occurs at night, it’s known as nocturnal hyperhidrosis. And because our bodies actually cool down a degree or two during sleep, nocturnal hyperhidrosis can be an indicator of an underlying problem or condition.

One possible cause of night sweats in men is low testosterone, which can be identified via a simple blood test. It’s a hormonal condition that becomes more common as men age. Low testosterone has been linked to being overweight and to Type 2 diabetes. Because it can also be a sign of infection; liver, kidney or pituitary gland disease; or an autoimmune disease, a diagnosis of low testosterone can lead to additional testing.

Other medical conditions that can cause night sweats include hypoglycemia, infection, HIV and certain cancers, such as lymphoma or leukemia. Medications for depression, diabetes and hormone treatments can also play a role. And, as we mentioned earlier, so can alcohol and tobacco use. Researchers in Spain tied night sweats in some patients to gastroesophageal reflux disease, often referred to as acid reflux. This is when the band of muscle at the base of the esophagus is no longer able to prevent the contents of the stomach from flowing backward.

As you can see, night sweats have a number of different triggers. Unfortunately, this makes it difficult to pinpoint the source. If your husband’s episodes continue and his doctors don’t have any thoughts on the issue, we think it would be worthwhile to seek another opinion.

(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: Even before the pandemic, I had trouble with sleep. It’s hard to fall asleep and to stay asleep. I don’t want to use any pills or medicines. Are there nondrug approaches that can work? What about lavender, CBD or magnesium?

Dear Reader: In the past year, stress, fear, worry and the unexpected changes to daily routines due to the coronavirus pandemic have caused a spike in the number of Americans struggling with sleep. We wish there were a quick and easy fix, but reclaiming the ability to get a good night’s sleep is a process. It takes consistency and discipline, and even then, the path to success is often an uneven trajectory.

Start with good sleep hygiene. That means a sleep environment that’s dark, cool and quiet. Eye shades, ear plugs and lighter bedding can help. Our bodies’ internal clocks run on chemical triggers tied to the waxing and waning of daily light. We’ve already affected those signals with our artificially lit world. New research continues to suggest that the blue light from electronic screens also scrambles the brain’s sleep signals and plays a role in sleep issues. So, in addition to choosing and sticking to a regular bedtime, it’s very important to stop looking at screens -- not even a quick peek at your phone -- for at least a few hours before bedtime. (We warned you this would take discipline.)

When used in conjunction with other sleep hygiene practices, the scent of lavender has been found to help with both sleep quantity and quality. So have meditation, deep breathing and relaxation techniques, when practiced consistently.

Once that’s all taken care of, you’re ready to consider nonpharmacologic approaches to insomnia. You asked about magnesium, a mineral that’s crucial to our body’s functions. It’s important to bone density, normal heart rhythm and blood pressure control. Research shows that many American adults don’t get the recommended daily 320 milligrams needed for women and 420 milligrams for men. Some small studies have linked magnesium to longer sleep duration and better-quality sleep in older adults. Magnesium supplements are available, of course, but we recommend adjusting your diet instead. The mineral is abundant in high-fiber foods like nuts, seeds, whole grains, beans and dark leafy greens. And good news for chocolate lovers -- an ounce of dark chocolate has 65 milligrams, which is 16% of your daily requirement.

As for cannabidiol, better known as CBD, the jury is still out on its efficacy as a sleep aid. CBD is one of the many cannabinoid compounds found in cannabis, which, because it doesn’t have psychoactive properties, won’t get you high. Some studies have found it can improve sleep duration and sleep quality, but the effects were spotty and not sustained over time. The manufacturing process of CBD remains unregulated, and it’s still illegal in some states. There’s also evidence that it can interfere with the efficacy of some prescription drugs. Some people find it helpful, but more study is needed for a definitive understanding of its role in sleep.

(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 am 75 years old, and I donate blood as often as they will accept me. However, I’m often anemic and get rejected. I eat a spinach salad every day, and fish, chicken or beef, plus veggies, for dinner. I’ve been double-dosing on iron supplements, but I’m still anemic. How concerned should I be?

Dear Reader: First, thank you for being a regular blood donor. Thousands of people each day are in need of blood or platelets. These can’t be manufactured and can come only from donors, so volunteers like you are saving lives. According to the Red Cross, the blood and blood products from each blood donation have the potential to save three lives.

In order to protect both the donor and the recipient, each donation is screened for a range of disease markers. The blood is also tested for anemia. Anemia occurs when someone lacks enough hemoglobin to carry adequate amounts of oxygen from the lungs to the tissues throughout the body. Hemoglobin is the protein that makes it possible for oxygen to move from the lungs to the blood, and then from the blood to the tissues.

Mild cases of anemia can be symptom-free. In fact, becoming a blood donor is a common way that people are first made aware of their condition. People with moderate or severe anemia can experience fatigue, breathlessness during even mild exertion, headaches and pale skin, and they can become easily chilled. Without enough red blood cells for their own optimal health, people who are anemic are ruled out as potential blood donors.

With your diet and the use of iron supplements, you’ve taken steps to address iron-deficiency anemia. However, the fact that you continue to be flagged as anemic does raise some concerns.

If you haven’t done so already, we think it would be wise to have a G.I. evaluation. This is to rule out occult bleeding, which is a loss of blood within the gastrointestinal tract that isn’t immediately visible. When you lose blood, you lose iron, which is essential to hemoglobin’s ability to carry oxygen. A common cause of occult bleeding is peptic ulcers, which are sores that develop on the lining of the stomach and the upper part of the small intestine. They can be caused by bacteria or anti-inflammatory drugs. Gastrointestinal bleeding is also a possible side effect of some blood-thinning medications. Occult bleeding may also arise due to inflammatory bowel disease, hemorrhoids, anal fissures, tumors or colon polyps.

Blood from the G.I. tract can usually be detected via a fecal blood test. If the results of a fecal blood test are positive, the next step would be a series of tests that use a scope to examine the upper and lower G.I. tracts to locate and identify the source of the bleed.

In addition to the causes of occult bleeding that we already mentioned, chronic anemia can be a sign of more serious conditions, including immune disorders, long-term infection and certain cancers. We hope that you will work with your doctor to identify the cause of your recurrent anemia.

(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.)