The controversy continues over the possibility that frequent exposure to electromagnetic fields from cell phones and other cordless devices increases the risk of brain tumors and cognitive dysfunction. That’s been hard to prove definitively, and many mainstream researchers dismiss the risk as alarmism.
But an international collaborative team of Canadian, US, and European researchers recently discovered something that may prove harder to dismiss: in some individuals, the 2.4 GHz pulsed signals emitted by a cordless phone system reliably produce measurable and clinically significant disruptions in cardiac rhythm.
In an elegantly series of experiments designed and led by Magda Havas, PhD, of the Environmental & Resources Studies Department at Trent University, Canada, researchers showed that 40% of a cohort of 25 generally healthy volunteers had marked increases in heart rate, arrhythmias, and other disturbances in heart rate variability (HRV) following exposure to a cordless phone base station actively emitting 2.41 GHz pulsed microwave signals.
Fields of this frequency are also emitted by many wireless routers and other WiFi technology.
This is the first objective evidence of cardiovascular effects associated with wireless EMF exposure, and it lends quantitative vindication to the concept of “electrohypersensitivity,” the sense some people have that they become physically ill when close to EMF fields from cell phones, microwave ovens, computers, fluorescent lighting systems, and WiFi networks.
Simple Set-Up, Striking Stats
Dr. Havas’ team continuously monitored HRV in the 25 people, ranging in age from 37 to 79, who were in a supine position for the duration of the experiment. They subjected the volunteers to 3-minute intervals of exposure to a cordless phone base station placed 30-50 cm (approximately 2 feet) from their heads. The subjects and the monitors were blinded as to whether the base station was actually plugged into a live outlet and emitting signals or not.
The tests were conducted in two Colorado locations (Golden & Boulder), and the investigators carefully measured and accounted for background EMF. They used a LifeSource UA-767 digital blood pressure monitor, and the NervExpress HRV monitoring system, which gives comprehensive information about autonomic activity, particularly the balance between the sympathetic and parasympathic branches
After baseline measurements, the subjects underwent a series of exposures in which the phone base station was connected to an active outlet (true exposures) or a false outlet (sham exposures). All HRV data were read and interpreted by an independent reader not present at the experimental sites.
Most subjects (15 of the 25) did not show detectable cardiovascular responses to the EMF. However, 40% (10 of 25) showed statistically significant increases in heart rate of 10-30 bpm over baseline. Four volunteers went into overt tachycardia, within 1-2 seconds of exposure to the live and radiating base station. In one subject, heart rate jumped from 61 bpm at baseline to 154 bpm on exposure.
The HRV profile in those who showed CV changes was characterized by a strong increase in sympathetic activity, and down-regulation of parasympathetic activity, suggestive of an adrenalin-mediated “fight or flight” stress response
Fortunately, the sympathetic overdrive and attendant cardiac changes were transient and returned to baseline patterns within seconds after the EMF emission was cut off (ie, the base station was unplugged from the live outlet).
The data were published October 22, 2010 in a special edition of the European Journal of Oncology, focused entirely on non-thermal biological and clinical effects of EMF on living systems. This monograph was jointly sponsored by the International Commission for Electromagnetic Safety and National Institute for the Study and Control of Cancer and Environmental Diseases (read Dr. Havas’ paper here)
In addition to Dr. Havas' heart rate paper, this special edition includes studies of EMF impact on carcinogenesis, cognitive function, the integrity of the blood brain barrier, endocrine and reproductive function.
Corroborating Subjective Experience
The autonomic disruptions shown by the HRV monitor correlate well with the sort of symptoms reported by many electrosensitive people, including: arrhythmia & palpitations, altered blood pressure, dizziness, nausea, fatigue, and sleep disturbances.
Of the latter two, Dr. Havas points out that, “When the sympathetic nervous system is stimulated and the parasympathetic is suppressed, the body is in a state of arousal and uses more energy. If this is a constant state of affairs, the subject may become tired and may have difficulty sleeping.”
The study is important because it provides objective corroboration for symptoms that doctors—or the patients themselves—often dismiss as imaginary or “stress-related.” In fact, they are stress-related, but the source of stress may be electronic.
Prior to the actual experiment, subjects were questioned on their self-perceived electrosensitivity. One third indicated that they did not know if they were electrically sensitive, 16% said they had little sensitivity, and 8% felt themselves to be not sensitive at all. Forty percent believed themselves to be moderately to extremely sensitive, noting that prolonged exposure to EMF-emitting devices could bring on phenomena like poor memory, difficulty concentrating, eye problems, sleep disruption, headaches, dizziness, heart palpitation, and arrhythmia.
It is interesting that 40% of the volunteers did turn out to be responsive to EMF according to the CV monitor. There was some overlap between self-perceived sensitivity and objective autonomic responsiveness, but the correlation was far from exact. Five of the subjects over-estimated their sensitivity (ie, they considered themselves ‘sensitive’ but did not respond to provocation), and two underestimated it.
A New Diagnostic Technique?
In an interview posted on the website, www.electromagnetichealth.org, Dr. Havas said this study began as a quest to find an objective way of evaluating claims of electrohypersensitivity. Ultimately, she hopes the findings will help prevent the unnecessary and reflexive over-medication of people whose heart symptoms are driven simply by proximity to “hot” EMF sources.
“Doctors, especially cardiologists, really need to know about this. They could very well be misdiagnosing some of their patients.” The technique used in the study--HRV monitoring with provocation via exposure to an EMF-emitting device--could be used clinically.
The real question is not, “Is EMF a health risk?” but rather, “For whom is it a health risk, how do we detect the risk, and how do we help sensitive people minimize exposure? She estimated that roughly one-third of all adults is somewhat sensitive to EMF fields, and between 3% and 5% react strongly enough to cause clinically significant, potentially debilitating problems. The problem is, you can’t tell who is who just by looking.
HRV monitoring is inexpensive, widely accessible, easy to use, and powerful in terms of the information it can give. “You can do the provocation studies in about 10 minutes, so in principle you could do this with patients with intermittent heart problems that seem unrelated to any other symptoms or risk factors for heart disease,” said Dr. Havas. The major caveat is that you need to ensure that the testing space is clean of extraneous wireless EMFs or “dirty” AC power lines.
Beyond Cell Phones
This study assessed the impact of EMF from a specific AT&T cordless phone system. Can the findings be generalized to other devices?
While a lot more research needs to be done using a wide variety of devices using different frequencies, Dr. Havas believes there is a general physiological principle at work, and that people who are sensitive to EMFs will likely have noxious responses to many different types of equipment.
Cell phones have been at the center of the current storm about EMFs. Concern about brain tumor risk prompted the City of San Francisco to pass an ordinance in June requiring cell phone retailers to post point-of-sale information about potential neurological risks from EMFs beyond a Specific Absorption Rate (SAR) of 1.6 W/Kg---that’s most cell phones.
Advocates of the ruling, which had strong popular support, say it is a major public health victory; critics call it an empty albeit high-profile measure taken against a largely imaginary risk. A New York Times article entitled, “Should You Be Snuggling with Your Cell Phone?” only added fuel to the fire of controversy. Author Randall Stross reviews the inconclusive but still disturbing epidemiologic and experimental links between cell phone EMF and brain cancer. He also points out that the fine print in cell phone packaging materials recommends that the devices be held 5/8” to 1” away from the head.
Dr. Havas’ study is important for several reasons: it is based on measurable physiological parameters that correlate with symptoms; it shifts the focus away from hard-to-prove long-term health consequences like brain tumors and onto easily trackable, real-time phenomena like heart arrhythmias; and it underscores the fact that cell phones are only one component of the EMF fields blanketing our lives.
“Unlike cell phones that radiate microwaves only when they are either transmitting or receiving information, the cordless phone radiates constantly as long as the base is plugged into an electrical outlet,” she noted.
With the base station at roughly 2 feet from their heads—the equivalent of sleeping with a cordless phone on the nightstand--the study subjects absorbed a maximum EMF “dose” of about 5 mW/cm2. This is a mere 0.5% of the 1,000 mW/cm2 deemed “safe” in US and Canadian health guidelines. Yet these relatively weak fields could induce significant CV changes in some people.
“What this tells us is that those guidelines are not protecting the hearts of individuals who might be particularly responsive to EMF signals,” Dr. Havas said.
Dr. Havas is co-author, along with Camilla Rees, of an e-book entitled, Public Health SOS: The Shadow Side of the Wireless Revolution (2008), a comprehensive review of the science on EMFs and adverse health consequences. Purchase the book from http://electromagnetichealth.org/
Environmental epidemiologist Devra Lee Davis, author of, When Smoke Ran Like Water (2002), and The Secret History of the War on Cancer (2007), has a new book entitled, Disconnect: The Truth About Cell Phone Radiation, What the Industry Has Done to Hide It, and How to Protect Your Family. Learn more at: http://www.environmentalhealthtrust.org/