Q: I read Hillary Clinton’s latest book, in which she mentions doing alternate nostril breathing to relax. Is there any evidence this works?
A: Some, but the studies have been small, have mostly involved men, and have looked only at short-term effects.
Alternate nostril breathing—or nadi shodhana pranayama in Sanskrit, which translates to “channel purifications”—has been used in certain styles of yoga for centuries. In Clinton’s book What Happened (2017), a memoir of her experience running in the 2016 presidential election and coping with her devastating loss, she writes about practicing alternate nostril breathing with her yoga instructor and reports that she found the technique calming. The method involves inhaling through one nostril, then exhaling through the other, using your thumb and index finger to sequentially close off each nostril. For the next breath, you reverse the order, inhaling through the nostril from which you just exhaled. And so on. Though there is no definitive protocol, the cycle is often repeated for five to 15 minutes or so.
Researchers believe that alternate nostril breathing may help stimulate parasympathetic nervous system activity, which slows down heart rate and reduces blood pressure, among other benefits, or that it may reduce sympathetic nervous system activity (the “fight-or-flight” response)—or possibly a combination of the two. It may affect other parts of the brain as well, including the hypothalamus and the thalamus, which are part of the brain’s limbic system; this system regulates the body’s stress and relaxation responses.
A number of small studies have suggested that the technique may lead to small, short-term reductions in blood pressure and anxiety. But larger studies with longer follow-up are needed to come to any definitive conclusions on these or other health effects—as well as what manner of doing it may garner the most benefits (for example, if it’s better to start with one nostril than the other).
In any case, sitting quietly and breathing deeply and slowly is known to help reduce stress and promote relaxation, at least temporarily. So if you enjoy alternate nostril breathing and find it relaxes you (even if it’s only because you’re concentrating on your breathing and not obsessing over something else)—or if it’s a standard part of a yoga practice you regularly take part in—there’s no reason not to do it. (Hey, if it’s good enough for the first female presidential nominee…)
Also see Mind-Body Exercise: Tai Chi and Yoga.