It's that time again: it's dark at 5pm, and you’re spending more time inside around other people. Even my regular yoga classes are more crowded, and there is always one person who’s sneezing or coughing. It raises the question of how your yoga practice might keep you healthier during the winter months and if it's helpful when you do fall prey to seasonal illness.
To get a clearer handle on this, we need to look at the body’s infection fighting system, the immune system, and how yoga can influence it. Most folks think of the immune system as a defense program that monitors the body, looking for invaders in the form of bacteria, viruses,and other troublesome organisms. Once detected, the immune system goes into action to try and kick those invaders out and get us back to normal health. This is quite a simplistic view of the immune system, which we now know is intricately connected to most of the body’s other systems, including, importantly, the nervous and endocrine systems.
In fact, instead of just reacting to foreign invaders and mounting a defense, the immune system in now viewed as a sensory organ (like the eyes, ears, or skin), gathering all kinds of information, and is in a constant two-way communication with the brain, while also interacting with our endocrine system.
Numerous studies have demonstrated a huge list of physiologic benefits that come from regular practice of asana, pranayama, and meditation, finding improved respiratory function, endocrine balancing, improved immune function, increased energy levels, improved sleep, and lowered stress response. All of these will have positive effects on prevention and treatment of seasonal respiratory illness, if a regular practice is established, which is course the hard work we have to do as individuals. Going to class once or twice a week is not going to cut it. You will need to start doing some practice on your own at home.
If we just look at the effect of sleep on how well your immune system works, we can see how important yoga’s positive effects on sleep are. Research has shown that the immune system kicks in at night and does much of its heavy work during deep sleep. When sleep times are shortened, this has a very bad effect on your immune function. A 2011 study showed that people who are “short sleepers” getting 5-6 hours of sleep or less a night were at 50-percent increased risk of getting a viral infection. So the simple fact of longer and deeper sleep from regular yoga practice is going to have a great protective effect for us.
How do we decide which kind of yoga asana practice is best to prevent colds and flu? When we view the asana portion of our yoga practice as a kind of exercise, studies have shown that moderate, regular exercise increases at least one of the immune cells in the body, the natural killer cells, or NKs. So a gentle to moderately challenging yoga practice could have a similar benefit for fighting off those seasonal infections. But not all yoga styles will do. Several studies have shown that prolonged and heavy exercise can actually reduce immune efficiency and depress immune cell function. So long, physically intense practices would be better reserved for times when you are at less risk of catching a cold or flu.
When a cold does strike, reducing the intensity of asana to gentle or restorative, while increasing the time spent with pranayama and meditation, is most likely going to support the healing process. Poses like supported Cobbler's are great because they gentle open the chest, the head is elevated to help with nasal or sinus congestion, and the pose is generally a great resting place for the body. Pranayama practices that reduce stress (like a 1:2 ratio inhale:exhale ), and guided meditations, can be done is supported poses like this. As your symptoms improve, you can gradually ramp up your asana practice again.
Some day, a new adage about preventive practices may become commonplace: A Down Dog a day keeps the doctor away!