Low body temperature a cause for concern?

DEAR DR. ROACH » I am an 85-year-old female with an often low body temperature. I feel very warm, like I have a fever, but when I take my temperature it can be as low as 95 or 96. This has happened several times.

I’ve heard that a low temp is just the same as a high fever. I take numerous medications, including for my thyroid, which my doctor has had trouble regulating. What do you think? Could this be related? My normal body temp seems to run about 97. — D.C.

DEAR READER » Normal body temperature varies, both during the day (morning temperatures are lowest), among people (normal values in young adults range from 96 F (35.6 C) to 100.8 F (38.2 C), and across ages, with older people tending to have lower body temperatures by 0.4 F (0.2 C). So, 97 F is not necessarily unusual.

However, certain medical conditions can cause the temperature to be abnormally low. Low thyroid blood levels certainly can make temperatures lower, as can other endocrine abnormalities (especially diabetes, pituitary gland problems and adrenal insufficiency). Some people with chronic kidney disease have low temperatures. Some medications can affect body temperature; the most common are anti-psychotic medicines, barbiturates (almost never used anymore) and alcohol. There are very worrisome causes of low body temperature. Sepsis, a state of abnormal body equilibrium related to serious infection, can present with either fever or low body temperature, which probably is where you got the idea that low temperature is as bad as a fever. Of course, exposure to cold can cause low temperature (hypothermia), but that’s not what we are concerned about here.

Hopefully your doctor will get your thyroid regulated, but if your kidney function is OK, you’re not taking any of the medications listed and you are feeling fine, it’s much more likely that this body temperature is normal for you rather than being a sign of a serious condition.

DEAR DR. ROACH » Fifteen months ago, I ended up in the emergency room for five hours with tachycardia, palpitations, elevated blood pressure and pain on my front, right side below the ribs. EKG, cardiac enzymes and chest X-ray were normal. Discharged with no idea of the cause. The next day, my pulse/BP were normal until I sipped a cup of coffee and symptoms returned. Had cardiac stress test, sonogram and MRI of gastrointestinal organs. All normal.

My research indicates that my CYP1A2 enzyme (which metabolizes caffeine in the liver) is now non— M.S.

DEAR READER » I admire your research, but the way caffeine is metabolized in the body is more complicated. Some people do have unusual copies of the gene for CYP1A2, and are very sensitive to small amounts of caffeine. Other people are very tolerant, and can do fine with even large amounts of caffeine right before bed. Two other genes, ADR and PDSS2, can affect caffeine metabolism.

I don’t think your enzyme stopped working. Over time, many people become more sensitive to the effects of caffeine, and as we age, metabolism does tend to slow down, and the heart can get more irregular. If avoiding caffeine keeps your symptoms away, I would recommend that you continue to do so.

Contact Dr. Roach at ToYourGoodHealth@med. cornell.edu.