How exercise fights anxiety and depression

NEW YORK – When it comes to mental health, most treatments for conditions like depression or anxiety come with caveats. Medications work for some symptoms, but can exacerbate others. Cognitive behavioural therapy is effective for many patients, but not all.

But there is one strategy that seems to work for most people and almost all experts endorse, and that is regular exercise.

Decades of research have established that exercise has a positive effect on mental health. In studies of patients with mild to moderate depression, for example, a wide range of exercise regimens has been shown to be as effective as medications like selective serotonin reuptake inhibitors (though the best results generally involve a combination of the two).

Moving regularly can improve sleep and reduce stress. While there is good evidence for the mental health benefits of exercising for about 45 minutes, three to five times a week, even just a few minutes of walking around the block can have positive effects.

“Is this walk going to do anything?” said associate professor Jennifer Heisz at McMaster University in Canada and the author of Move The Body, Heal The Mind. “The answer is yes. It’ll do way more than you think.”

Why is exercise good for mental health?

It is hard to find a brain process that does not improve with regular movement. Exercise boosts blood flow, decreases inflammation and improves brain plasticity. It also triggers the release of many mood-boosting chemicals, including beta-endorphins and cannabinoids – which both play a role in the “runner’s high” feeling – norepinephrine, dopamine and serotonin.

More recent science has found that consistent exercise can change the underlying structure of some brain regions.

“You’re increasing the birth of new neurons within the brain,” said psychiatry professor Mazen Kheirbek at the UCSF Weill Institute for Neurosciences. By creating new brain cells, exercise “changes, over many days, how your brain functions”.

Adults typically do not generate many new neurons and it happens only in a few places, namely in the hippocampus, which is tied to mood and memory. People suffering for long periods from depression or stress tend to have smaller hippocampi than others, with fewer new neurons and less plasticity.

According to research on both humans and laboratory animals, there is essentially a reverse effect – more neurons and a greater ability to adapt – after regular exercise, Prof Kheirbek said. This is especially clear in people with more severe anxiety or depression, who generally see larger improvements over time.

Are certain workouts more beneficial than others?

Scientists have not yet determined whether, say, running is better than weightlifting for improving mental health.

For one thing, a lot of exercise studies are performed on animals, and it is much easier to get a mouse to run in a wheel than lift weights, said Dr Brett R. Gordon, a postdoctoral fellow at the Penn State Cancer Institute.

It is also hard to compare different kinds of exercise because the effects can vary for different people, and participants bring their own biases about exercise to a study. Someone who already enjoys running may be more likely to experience a mood lift after other forms of cardio.

However, there is some evidence suggesting that activities like yoga or taiji are better for relieving symptoms of anxiety than, say, boxing or basketball. This may be because these fluid, low-intensity workouts often employ meditative or mindful techniques that have been repeatedly proven beneficial for mental health.

“The mind-body connection, it can be present in all forms of exercise, but it’s reinforced very much in yoga and taiji,” Prof Heisz said.

More intense exercise – almost by definition – increases stress levels. Some of Prof Heisz’s research suggests that people who report more symptoms of anxiety tend to see fewer mental health benefits from intense workouts in the short term than those with little or no anxiety.

But several experts, including Prof Heisz, pointed out that over time, regular intense exercise can still have significant benefits to people with anxiety, if they stick with it and listen to their bodies.

In fact, a large 2023 review suggested that high-intensity interval training workouts can be more effective at alleviating depression and anxiety symptoms than lower-intensity workouts.

But none of this matters if a patient does not feel motivated to do it, said physical activity researcher A’Naja Newsome at the University of Central Florida. With depression in particular, she said, it can be difficult to get started, or to enjoy it.

“When you think about someone who is experiencing depressive symptoms, it’s often lack of interest, lack of energy, lack of mood,” she said.

She stressed the importance of beginning with easier, lower impact activities and having an exercise community or workout buddy to keep you going. And if you are just starting out, a daily walk might be more sustainable than an intense workout.

“While I’m a huge proponent of resistance training and aerobic exercise,” she said, “if someone doesn’t like it, he or she doesn’t enjoy it, he or she is not going to do it.” NYTIMES