David Blaine, a self-declared endurance artist, has pushed his physiological limits to unprecedented extremes. He was buried alive for a week and frozen in a block of ice for three days. As a child, he was captivated by stories of Houdini holding his breath for over three minutes and started practicing this feat himself. According to his accounts, he matched Houdini’s breath-holding record by the age of 11.
As it turns out, Houdini’s record wasn’t all that impressive. As Blaine investigated the extreme limits of the human capacity for breath holding, he learned that humans could rival other aquatic mammals with their underwater capabilities. For example, after training, free divers regularly hold their breath longer than three minutes as they dive to depths exceeding 600 feet. Some have exceeded nine minutes after taking deep breaths of ordinary air. After breathing pure oxygen, the duration of breath holding in humans can exceed 16 minutes. Blaine decided to test how long he could go without breathing.
After consulting with physicians, Blaine initially lost 50 pounds. He then began a training regimen to maximize the efficiency of his body’s use of oxygen. He learned to slow his heart rate to about 38 beats per minute (bpm), which declined further to 12 bpm as he was holding his breath. In contrast to the free divers who are obviously expending energy, Blaine chose to remain still and hold his breath underwater for as long as possible (a discipline known as static apnea), to maximize his efficient use of oxygen. Each morning he practiced holding his breath for 44 minutes out of a total of 52 minutes, taking breaks of course. After planning to perform the pure oxygen, static apnea breath-holding stunt on Oprah Winfrey’s television show, he began sleeping in a hypoxic altitude tent, a structure that provides a low-oxygen environment similar to that found in high altitudes, in an attempt to increase his red blood cell count. Because red blood cells transport oxygen throughout the body, the body generates more of them to compensate for chronically low oxygen levels (Wehrlin, Zuest, Hallon, & Marti, 2006). Obviously, Blaine was serious about achieving this goal.
Did this breath-holding training regimen pay off? Blaine later reported that the breath-holding duration test got off to a scary start. To his dismay, the elaborate stage set, crew, and audience were distracting and thereby impaired his ability to control his heart rate, which was visible to everyone on a large monitor. After being submerged in the tank and securing his feet so that he wouldn’t float to the top, his typical, extremely low starting heart rate was suddenly 120 bpm…and never changed throughout his entire breath-defying attempt. Much to Blaine’s chagrin, the background setting for this endurance test was a critical factor that he should not have ignored.
Blaine knew that his high heart rate was wasting precious oxygen. After eight minutes, he was certain he would fail to break the breath-holding record in humans of 16 minutes. At 10 minutes he felt blood shunting from his fingers and toes to his core vital organs; at 11 minutes he felt throbbing in his legs; at 12 minutes his arm felt numb, causing him to think that he was having a heart attack. The next few minutes brought on chest pains and, not surprisingly, an overwhelming urge to breathe! Blaine could tell from the heart monitors that his heart had an insufficient supply of blood, wildly bouncing from low to high heart rates. At 16 minutes, he removed his feet from their restraints so he could be removed from the tank easily if he passed out. Then he heard the cheers from the audience confirming that he had indeed exceeded the world record for breath holding. Like a true endurance artist, he pushed the limits, finally emerging from the tank after 17 minutes and 4 seconds. In a lecture given later, Blaine reported that he felt his best when he was able to push through the pain to display superhuman abilities (Blaine, 2009; Tierney, 2008).
Behind the Scenes
How did David Blaine demonstrate such control over his physiology? Which parts of his brain allowed him to exert control over essential functions? As opposed to behaviors such as walking or reaching that are known as somatic functions under voluntary control, the moment-by-moment, life-sustaining functions of our internal organs that are known as autonomic functions are typically considered involuntary.
The view that autonomic functions are beyond individual control was challenged in the 1960s by physiological psychologist Neal Miller. He conducted a series of studies that provided evidence that rats could control their heart rates and dogs could control their salivation in anticipation of a water reward (Miller, 1969; Miller, 1978). These findings remain controversial due to difficulty replicating the original studies (Dworkin & Miller, 1986), yet scientists continue to be intrigued by them. Various biofeedback techniques are regularly used in laboratories demonstrating that, with the appropriate feedback, humans can alter functions such as heart rate and blood flow. Obviously, if such techniques could be identified as consistently effective in altering such autonomic functions, especially outside of the controlled laboratory, it might lead individuals to opt for biofeedback over pharmacological treatment.
Neuroscientists have more recently identified a few brain areas that may facilitate the shift from involuntary to voluntary control of autonomic functions. A prime suspect is the insular cortex (also known as the insula), a brain area located in the most recently evolved cerebral cortex, which provides representations of the “state of the body” to other relevant brain areas by integrating input both from within the body and from the external environment (Craig, 2010a; Craig, 2010b). In the past, scientists described the insular cortex as being involved solely in more basic automatic functions. However, recent data indicate that these descriptions were premature (Churchland, 2011). The insular cortex’s function in facilitating interoception, the ability to monitor the body’s internal processes (Craig, 2010a; Craig, 2010b), makes it a likely candidate for Blaine’s extraordinary ability to monitor and control his physiological processes.
Although no convincing evidence exists that David Blaine has an overactive insular cortex, research suggests that patients with higher levels of activity in this area could suppress ongoing chronic pain (deCharms et al., 2005). Another study reported that subjects able to accurately judge the timing of their own heartbeats exhibited increased activity in the area of the insular cortex, measured by the neuroimaging technique functional magnetic resonance imaging (fMRI) (discussed in Chapter 1; Critchley, Wiens, Rotshtein, Ohman, & Dolan, 2004).
Considering the complexity of the nervous system, multiple brain areas are likely involved in the biofeedback techniques used to monitor physiological processes such as heart rate by Blaine. Yet research provides compelling evidence that our awareness of internal contexts is influenced by the insular cortex.