Monitor on Psychology - December 2011 - (Page 51)
help people prone to anxiety become less likely to panic when they experience those fight-or-flight sensations. After all, the body produces many of the same physical reactions — heavy perspiration, increased heart rate — in response to exercise. They tested their theory among 60 volunteers with heightened sensitivity to anxiety. Subjects who participated in a twoweek exercise program showed significant improvements in anxiety sensitivity compared with a control group (Depression and Anxiety, 2008). “Exercise in many ways is like exposure treatment,” says Smits. “People learn to associate the symptoms with safety instead of danger.” In another study, Smits and his colleagues asked volunteers with varying levels of anxiety sensitivity to undergo a carbon-dioxide challenge test, in which they breathed CO2enriched air. The test often triggers the same symptoms one might experience during a panic attack: increased heart and respiratory rates, dry mouth and dizziness. Unsurprisingly, people with high anxiety sensitivity were more likely to panic in response to the test. But Smits discovered that people with high anxiety sensitivity who also reported high activity levels were less likely to panic than subjects who exercised infrequently (Psychosomatic Medicine, 2011). The findings suggest that physical exercise could help to ward off panic attacks. “Activity may be especially important for people at risk of developing anxiety disorder,” he says. Smits is now investigating exercise for smoking cessation. The work builds on previous research by Bess Marcus, PhD, a psychology researcher now at the University of California San Diego, who found that vigorous exercise helped women quit smoking when it was combined with cognitivebehavioral therapy (Archives of Internal Medicine, 1999). However, a more recent study by Marcus found that the effect on smoking cessation was more limited when women engaged in only moderate exercise (Nicotine & Tobacco Research, 2005). Therein lies the problem with prescribing exercise for mental health. Researchers don’t yet have a handle on which types of exercise are most effective, how much is necessary, or even whether exercise works best in conjunction with other therapies. “Mental health professionals might think exercise may be a good complement [to other therapies], and that may be true,” says Blumenthal. “But there’s very limited data that suggests combining exercise with another treatment is better than the treatment or the exercise alone.” Researchers are starting to address this question, however. Recently, Madhukar Trivedi, MD, a psychiatrist at the University of Texas Southwestern Medical College, and colleagues studied exercise as a secondary treatment for patients with major depressive disorder who hadn’t achieved remission through drugs alone. They evaluated two exercise doses: One group of patients burned four kilocalories per kilogram each week, while another burned 16 kilocalories per
DeceMber 2011 • Monitor on psychology
kilogram weekly. They found both exercise protocols led to significant improvements, though the higher-dose exercise program was more effective for most patients (Journal of Clinical Psychiatry, 2011). The study also raised some intriguing questions, however. In men and women without family history of mental illness, as well as men with family history of mental illness, the higher-dose exercise treatment proved more effective. But among women with a family history of mental illness, the lower exercise dose actually appeared more beneficial. Family history and gender are moderating factors that need to be further explored, the researchers concluded. Questions also remain about which type of exercise is most helpful. Most studies have focused on aerobic exercise, though some research suggests weight training might also be effective, Smits says. Then there’s the realm of mind-body exercises like yoga, which have been practiced for centuries but have yet to be thoroughly studied. “There’s potential there, but it’s too early to get excited,” he says. buffering the brain It’s also unclear exactly how moving your muscles can have such a significant effect on mental health. “Biochemically, there are many things that can impact mood. There are so many good, open questions about which mechanisms contribute the most to changes in depression,” says de Groot. Some researchers suspect exercise alleviates chronic depression by increasing serotonin (the neurotransmitter targeted by antidepressants) or brain-derived neurotrophic factor (which supports the growth of neurons). Another theory suggests exercise helps by normalizing sleep, which is known to
Video: Watch Temple University exercise psychologist Michael Sachs, PhD, discuss how to get reluctant exercisers off the couch.
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