How does headstand affect cerebral blood flow?
Research Study At A Glance
Research Study At A Glance
The Research Question Asked
Does headstand increase blood flow to the brain?
Type of Study
Clinical research study
Study Participants (Sample)
Sample size: 5 men and 15 women
- 20 total participants
- Between ages 10-59
- At least one year of yoga experience
- Capable of and familiar with doing headstand
Methods
The researchers compared blood flow to the internal carotid artery when participants were lying down in a supine position with blood flow at the same location when participants were holding a headstand.
Results
- Headstand did not increase blood flow in the internal carotid artery for otherwise healthy participants.
Conclusion
The body continues to autoregulate blood flow to maintain it within certain healthy values even if we are in headstand.
Background
There are many beliefs that surround the various yoga practices with respect to what the impacts of the practices are physiologically. Some of these beliefs arise from interpretation of classical Sanskrit texts which describe the practices. Other beliefs don’t seem to have arisen from a particular source, but are often repeated in the yoga community. Slowly, in recent years, the research community has started to take a closer look at some of these beliefs to see whether the claim of a particular effect of a yoga practice or posture can be validated in a laboratory setting. In the current study that I’m summarizing here, the research team examined the idea that doing headstand (sirsasana) increases blood flow to the brain.
Research question
Does headstand increase blood flow to the brain?
Research methods
The study included 20 total participants, five men and 15 women, who were all capable of and familiar with doing a headstand independently. All participants except one had at least one year of yoga experience. They ranged in age from 10-59; median age was 43. Of the study participants, 17 were evaluated at an altitude of 2000 m and the rest were evaluated at sea level.
The researchers measured blood flow using an ultrasound examination of the internal carotid artery. Blood flow was measured when participants were lying on their back in a supine position, then in headstand, and then again in a supine position.
Results
- 17 of 20 participants did not experience increased blood flow in the internal carotid artery during headstand
- 3 of 20 participants did experience increased cerebral blood flow in the internal carotid artery during headstand and these participants were found to have increased intraocular pressure during headstand as well
Why is this relevant to yoga practitioners?
Headstand is a posture common to most styles of yoga asana and questions often come up from practitioners about what happens physiologically when we go upside down. In this research the authors verified that autoregulation of cerebral blood flow, the body’s method of maintaining blood flow to the brain within certain healthy values, continues as normal when we are upside down in headstand, as long as we are otherwise healthy.
Questions also come up around various aspects of headstand’s safety. What’s also relevant to yoga practitioners in this research is that the authors reported a small percentage of their participants actually did experience an increase in blood flow through the internal carotid artery when doing headstand. These same participants also experienced increased intraocular pressure, which is commonly considered a contraindication for doing headstand. The researchers suggested that, in the case of these three participants, their body’s autoregulation system of blood flow was not functioning properly. They suggested that any dysfunction in that system should also be considered a contraindication for doing headstand and other inverted postures.
Conclusion
Research suggests that in otherwise healthy practitioners, our body is able to autoregulate our blood flow even when we are upside down. If however, we experience any dysfunction with that system, we should avoid inverted postures such as headstand. And we should consult with our doctor or appropriate medical professional.