It is not so clear that a person can use exercise as a substitute for medication as a depression treatment. Dreamstime/TNS

• Share

PRINT

Q: I started exercising regularly, jogging for about 40 minutes five times per week. Does that mean I can stop my antidepressant medication because my body is now creating the same antidepressant effect on its own?

A: It’s great that you’re devoting yourself to regular exercise. There is no question that it is good for your whole body, including your brain. It can lift mood, quell anxiety, improve sleep, increase energy and enhance self-esteem.

There is biological evidence, in fact, that exercise provides some of the same positive effects on the brain that antidepressants do.

But it is not so clear that you can use exercise as a substitute for medication as a depression treatment. It may work out for a few people to make such a switch, but it’s not a sure bet at all.

You definitely don’t want to stop or even lower your dosage without consulting with the prescribing clinician. Even if you maintain your exercise regimen, there is a risk of relapse when you stop an antidepressant.

As much as we’re learning about the biology of depression, our knowledge is not precise enough for us to be able to predict how different treatments will affect a given individual. We do know — from both the biological and environmental point of view — that there are many types of depression and that one treatment does not fit all people.

Now, back to the positive effects of exercise.

Jog long enough and you may get an “endorphin high” that lasts for a short period. Exercise regularly and your brain begins to change for the better. The blood flow and energy supply to nerve cells improve. Those cells get healthier, grow bigger, branch out and make new connections. New nerve cells are even created, a process called neurogenesis.

Anyone who exercises regularly may therefore be tempted to cut back on an antidepressant dose. Proceed with caution, however. A lot of biological processes are still invisible to us.

Different antidepressants have different “mechanisms of action.” They create the end result through different biological processes. Thus, a given medication may help in ways that exercise doesn’t touch. (The converse is also true: Exercise touches things that antidepressants don’t.)

It may be that — in your case — the antidepressant treatment and the exercise are complementing each other. For example, the antidepressant may be tweaking your motivation centers, providing you the impetus to go for a run.

It sounds like you are feeling helped by both the medication and by the exercise. So, it’s a good time to have the medication discussion with your doctor.

Q: What does heart rate variability mean and how is it related to our health?

A: Heart rate variability (HRV) is a measure of the variation in time between each heartbeat.

We know that a heart rate that’s too slow, too fast or irregular can signal a problem, so it’s only natural to think that a steady, regular pulse is a sign of a healthy heart. But for HRV, multiple studies suggest that having a high number is more likely to be associated with better health.

A highly variable heartbeat means that the interval between beats fluctuates, although only by a fraction of a second. For example, if your heart rate is 60 beats per minute, instead of one second between beats, you’d have 0.8 seconds between some beats and 1.2 seconds between others.

Heart rate variability is controlled by a primitive part of the nervous system called the autonomic nervous system (ANS). The ANS works behind the scenes, automatically regulating our heart rate, blood pressure, breathing and digestion, among other key tasks.

The ANS is subdivided into two large components: the sympathetic and the parasympathetic nervous system, also known as the fight-or-flight mechanism and the relaxation response.

A high HRV seems to signal a healthy heart because it reflects the heart’s ability to respond quickly to rapid changes occurring throughout the body.

In a healthy person, HRV should increase when your heart rate drops, as it does during relaxing activities such as reading or meditating. HRV decreases as the heart rate rises, such as when you exercise or are under stress.

In fact, HRV changes constantly, both throughout the day and from day to day. But chronic stress, poor sleep, lack of exercise and an unhealthy diet can disrupt the balance, and your fight-or-flight system can shift into overdrive.

Low HRV is associated with an increased risk of cardiovascular disease. People with high HRV, on the other hand, tend to have higher fitness levels and be more resilient to stress.

However, there isn’t a recommended HRV value because it varies widely, depending on your age, sex, fitness level, medical history and genetics.

Many smart watches and wearable health monitors feature programs that measure HRV, though it’s not clear just how accurate or reliable these readings are.

While HRV has been linked to overall physical fitness, the correlation between changes in HRV and how your autonomic nervous system is functioning will require more research. Still, if you decide to use HRV as another piece of health data, do not get too confident if you have a high HRV, or too worried if your HRV is low.

Howard LeWine, M.D., is an internist at Brigham and Women’s Hospital in Boston and assistant professor at Harvard Medical School. For additional consumer health information, visit health.harvard.edu.

© Harvard University. Distributed by Tribune Content Agency, LLC.