When Nerve Pain Calls for MRI

I am a 160-lb, 58-year-old male who runs on average 15 miles a week at 9 or 10 minute pace. I had also been using weights three days a week to strengthen my upper body, but three months ago I started experiencing debilitating symptoms down my left leg that feel like sciatica. I have no direct back pain. The pain was severe enough at the time to cease both running and weight training. I began to make good progress with regular back stretching exercises, acupuncture, muscle relaxants, anti-inflammatories and chiropractic adjustments. I see a sports medicine doctor who oversees these treatments.

I had reduced my pain considerably in the mornings, with no pain for the rest of the day. I gradually started walking, then walking and running, then running for three miles. I was down to just the anti-inflammatory drug and regular stretching when I had a major setback a month ago, while I was out of town. I was unable to even stand from the terrible pain down my leg. I ran the day before this occurred without any problem.

I am back on acupuncture, avoiding the chiropractic, and making progress, though numbness on the bottom of my left foot continues. I walk as much as I can, which is only for about 10 minutes. How should I go about starting my weight training and running once the nerve heals?

Kevin Donahue
Woodland Hills, CA

I think your spine is a likely source for your symptoms. Even without back pain, sciatica usually arises from the spinal nerve roots. Some practitioners diagnose piriformis syndrome as a sciatica source when back pain is absent. This is a deep muscle in the buttock that lies over or around the sciatic nerve. The notion is that the nerve gets compressed by this muscle when it is tight, spasmed or externally compressed, such as by a wallet. These scenarios are medically possible, but in reality probably very rare. The problem, if it is truly nerve related, is almost always the spine.

A combination of degenerative disc bulging and bony joint enlargement compresses an existing spinal nerve root, usually the lowest lumbar or the first sacral nerve. The majority of sciatica resolves. But your case is unique in that you are 58, you want to get back to running and you may not be getting better. I recommend an MRI study of your lumbar spine; recommendations for activity will be in part based on the results. This can also help the chiropractor determine how best to apply his/her skills.

The initial rehab sounds like it was appropriate. You will have to start from scratch again. When symptoms return like this, you need to see your doctor and work up the problem for a more definitive diagnosis. Generally speaking, return-to-running programs involve starting at a pain-free level and only increasing mileage by 10 percent per week.

Robert Scott, MD
San Diego, CA

Simply Stressed or Overtrained?

I've been running for several years, usually 30 to 35 miles a week. Lately I've been very tired. Running has become a chore, but I used to look forward to daily runs.

About a year ago at the blood bank where I usually donate two or three times a year, I learned I had low ferritin. The doctor there gave me some iron pills and asked me to return in a few months. I did, and he said my ferritin had gone up from 9 to 23, which was encouraging. After a few more months it went down to 20, and he said I should see my doctor.

I did, and he said there was nothing wrong with this, and I shouldn't take iron supplements because my hemoglobin was normal. My doctor said low ferritin was not the cause of my fatigue, and hinted it was psychological. What should I do?

Amy Abernathy
Bryn Mawr, PA

Ferritin is a measure of your iron store, and hemoglobin is the iron carrying protein in red blood cells that transports oxygen from your lungs to the rest of your body. Iron is transferred from the store to your bloodstream, as needed. There is much debate about whether low ferritin with normal hemoglobin can cause fatigue.

My feeling is that your low ferritin is not the cause of your fatigue, because ferritin does not transport oxygen like hemoglobin does. You should be able to increase your iron store by eating more iron rich foods, such as lean red meat or dark poultry.

As for your symptoms, I would look for other causes of stress. Our bodies react to the total amount of stress: physical, such as running, and emotional stress. I find that when I am stressed in areas such as family or job concerns, running loses some of its appeal. So stress in other aspects of your life could cause you to feel running is a chore.

You may also be burned out or stale, and perhaps need a change of routine to get you motivated again. Your symptoms sound like what I see in runners who are overtrained. They can also arise from not eating enough carbohydrate to provide the energy for an active lifestyle.

I would not worry about your ferritin level. I suggest you examine the stresses in other areas of your life, your running and eating habits. If you feel your running is stale, try something new, such as a new route, or running with a group, to spark your interest again. If you think you are overtrained, decrease your mileage for a couple of months. Perhaps you should try some other activities instead, such as bilking, or swimming, until you feel refreshed.

Nancy Evans, MD
Bend, OR

Sodium Consumption Concerns

Oddly, two running buddies recently developed hypertension. They are well above average athletes and I wonder what’s going on here.

I’m a 53-year-old female who has been running for 25 years, currently 35 miles per week. I am 5’ 5” and 120 lbs. I run a 5K in 24:30 and a marathon in about 4:15. I do tempo runs, long runs and speedwork.

I consume an enormous amount of salt, most often in the summer, when I actually crave it. I sweat profusely, but I do have a history of hypertension in the family. My blood pressure is okay right now (120/75), if slightly higher than the 110/60 from 10 years ago.
Without a lot of salt, my training schedule makes me very lethargic. Can my sodium intake be harmful? I really wish to avoid developing hypertension.

Kylie Hersthurder
Huntsville, AL

With a blood pressure of 120/75 and clearly a salty sweater, you are doing the right thing and should not worry unless you actually develop hypertension.

Athletes sweating in the summer sun should not abide by the dietary limit established for sedentary adults: 2,300 milligrams of sodium daily. As internist for the Oklahoma Sooners, I have found some OU football players, during two-a-day workouts, to lose five teaspoons of salt a day. Heat cramping and exhaustion result from lack of sodium. Never drink more than you sweat. Overdrinking, even fluids with sodium, can dilute blood sodium. If you gain weight during a long run, drink less next time.

If you see salt on your skin or clothing or sweat burns your eyes, you may need more salt than most people during a workout in the sun. Foods with lots of sodium include tomato juice, canned soup, pickles, pretzels and pizza.

Randy Eichner, MD
Oklahoma City, OK

As noted above, your desire for salt seems like your body’s appropriate response to your exercise regimen. You might obtain a home blood pressure monitor at your local pharmacy and monitor it twice a week. Keep a diary of these readings to be sure you’re on the right dietary track. While excess sodium does carry the risk of hypertension, the dangers of hyponatremia—dangerously low blood sodium—are worth reading up on as well.

Lloyd Lense, MD
Hauppauge, NY

Hypothyroid Meds Should Mitigate Performance Declines

I take 10 micrograms of the generic form of levothyroxine (brand name Levoxyl) for an underperforming thyroid gland. I’ve been doing this for seven years. I take the medication with a low-dose aspirin and, during the summer, Claritin. My internist tests for thyroid-stimulating hormone (TSH) each year. Last year it was 5.084. The year before, it was 5.1.

I began jogging almost three decades ago and got serious about running and entered my first races about three years in. I am now 63 years old, and run four days a week, with a base of two 4-milers and two 6-milers, with increases when I’m marathon training. I currently weigh 165.

Last year I dropped out of a marathon after 21 miles, then entered another marathon four weeks later, posting a 4:03:58. In both cases I ran at a comfortable 9:05 pace for 12 miles, then died. The struggle in the 13th mile has become more like what I would not encounter until 16-18 miles in previous decades.

Could my premature falloff be linked to my hypothyroidism? I’ve always understood the medication is to be used for maintenance and there shouldn’t be a wide swing even for a missed dosage. Might there be a cumulative effect over the weeks of longer runs that go along with racing prep?

Leonard Sirk
Colorado Springs, CO

There are multiple factors which may be affecting your marathon performance. First of all, performance decreases with age. Training will slow the rate of decline, but will not stop it.

Hypothyroidism can negatively impact performance, though on medications, this should be a minimal/negligible impact. Your TSH is at the upper end of normal limits (a high level is consistent with hypothyroidism); too much thyroid replacement can cause a number of medical problems. Your TSH levels are consistent over time, though levels do need to continue to be monitored. Adjusting the medication dosage so that your TSH is on the low side of normal would probably not have a significant impact on training and could cause side effects.

I think that you need to look at your training schedule and racing pace. It looks like your fastest miles are at the start of the race; most runners perform best with even or negative splits. Are you using too much energy (for your level of training) early in the race and paying for it in the middle of the race? Possibly incorporating a medium length run at planned marathon pace in your schedule will be helpful; start at 6 miles and gradually increase to 12 miles. This could replace your speedwork. Make sure that there is sufficient recovery between this and your long run. You might also consider working with a coach to tailor a training program to your needs.

Cathy Fieseler, MD
Tyler, TX

Your TSH is indeed at the upper end of the normal range (at least in most labs), so there is probably room to increase your thyroid replacement slightly (by 12.5 to 25 micrograms), followed by a repeat TSH in three months. If it has not decreased below your lab's lower limit of normal, your replacement dose may be more optimal.

In addition, though small variations in the amount of active thyroid hormone in each pill are probably not significant, some generic brands of levothyroxine are not considered reliably potent. I would suggest using the brand name Levoxyl for your replacement (it has the most consistent potency data).

Whether this minor thyroid abnormality is the reason for your relative decline in performance is uncertain, but these small changes are easy to accomplish and will allow you to test whether the thyroid is the culprit.

William M. Simpson, Jr., MD
Charleston, SC

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