Cell phones have become indispensable in the daily lives of men and women around the globe. As cell phone is now an integral part of modern telecommunications, concerns have mounted regarding the potentially harmful effects of radiofrequency-electromagnetic radiation (RF-EMR) from such devices. Given the immense numbers of users of mobile phones, even small adverse effects on health could have major public health implications.[1]

Mobile phone (MP) technology has grown significantly over the past decade and has become an essential part of our everyday lives. However, due to the widespread exposure to electromagnetic fields (EMF) from mobile communication systems, there may be some negative effects on health in the living environment. It is possible that EMF generated by MPs may have an influence on the autonomic nervous system (ANS), which modulates the function of the circulatory system.[2]

Recent years have witnessed rapid worldwide growth in the use of cell phone and enormous attention about its effect on human health. Mobile phones (MPs) radiation might induce or promote cancer, and the symptoms which are associated with their use include sleep disturbances, memory problems, headaches, nausea, dizziness and changes in the electroencephalographic activity.[3]

Today, heart problems have become the most frequent cause of death in the western world. The number of sudden cardiac deaths in the United States is estimated between 200.000 and 500.000 per year, with  50% to 70% being due to mechanisms related to arrhythmias.[4]

According to European Guidelines, the  specific  absorption  rate (SAR)  limit  for  hand­held  devices  is  2.0  W/kg  averaged  over  10 g  of  tissue. SAR  levels according  to  American  guidelines  requires  hand­held  devices  to  be  at  or below 1.6 W/kg  measured over 1.0 g of tissue. For whole body exposures, the limit is 0.08 W/kg. India  switched  from  the  European  limits  to  the  American  limits  for mobile  handsets  in  2012.[5]

HRV

The clinical relevance of heart rate variability was first appreciated in 1965 when Hon and Lee noted that fetal distress was preceded by alterations in interbeat intervals before any appreciable change occurred in the heart rate itself. During the 1970s, Ewing et al devised a number of simple bedside tests of short-term RR differences to detect autonomic neuropathy in diabetic patients.The association of higher risk of post-infarction mortality with reduced HRV was first shown by Wolf et al in 1977. In 1981, Akselrod et al introduced power spectral analysis of heart rate fluctuations to quantitatively evaluate beat-to-beat cardiovascular control. The clinical importance of HRV became apparent in the late 1980s when it was confirmed that HRV was a strong and independent predictor of mortality following an acute myocardial infarction. With the availability of new, digital, high frequency, 24-h multi-channel electrocardiographic recorders, HRV has the potential to provide additional valuable insight into physiological and pathological conditions and to enhance risk stratification.[6-8]

A cross-sectional (observational) study was conducted on 150 healthy young male in age group of 18-21 years. The subjects were divided into three groups according to their duration of mobile phone use [ <30 min/day (Group 1), 30–60 min/day (Group 2), and >60 min/day (Group 3)]. The subjects for study was taken up amongst the students studying in the Government Medical College and Rajindra hospital, Patiala. The subject selection is based on exclusion-inclusion criteria. Inclusion criteria: 1. Healthy young male in age group of 18-21 years were divided into three groups according to their duration of mobile phone use [ <30 min/day (Group 1), 30–60 min/day (Group 2), and >60 min/day (Group 3)].. Exclusion criteria: 1. Diagnosed Hypertensives 2. Renal and endocrine Disorders 3. Cardiovascular Disorders 4. Respiratory disorders 5. History of anxiety or depressive disorder Prerequisites: 1. The subject was be allowed to relax on a comfortable chair with the subject's back towards the recording machine. 2. The following anthropometric parameters was measured according to standardized techniques. - Height (cm) - Weight (kg) - Body mass index: It was calculated using Quetlet's Index [33] BMI = Weight (kg) / Height2 (in m) - Body Surface Area: It was calculated using Dubois & Dubois formula [34] BSA in m2 = 0.007184 x Weight0.425 (kg) x Height (m)0.725 METHOD OF RECORDING Heart rate of each subject was recorded by ECG monitoring, in RR mode (beat to beat), for 5 minutes at rest, in supine position, using ‘physiopac hardware’ by medicaid. Method: 1. Switch on the computer 2. Connect Physiopac Control unit with Computer systems through USB cable. 3. Connect Bio potential Junction boxes with channel no. 1 available on the front panel of the Physiopac control unit. 4. Insert the ECG disc electrodes in the sockets of Bio-potential junction boxes. 5. Click on the icon of Physiopac available on the computer screen 6. Fill user ID and password and then click at OK. 7. To make new subject entry click at ADD NEW. 8. Fill the details of the subject and click at SAVE button to save the subject data. 9. Click at NEW TEST and select the ECG parameter on channel 1.

The present study was conducted in 150 healthy young males in age group of 18-21 years. The subjects were divided into three groups according to their duration of mobile  phone  use [ <30 min/day (Group 1), 30–60 min/day (Group 2), and >60 min/day (Group 3)]. The subjects for study were taken up amongst the students studying in the Government Medical College and Rajindra hospital, Patiala.

Table:-1 Divisions of Groups according to duration of phone calls in a day

Table:-2 Mean and standard deviation of Anthropometric Parameters in Group 1

(Group 1 : <30 min./day)

The mean age (in years) of Group 1 was 18.60±0.75 The mean height (in centimeters) was 173.08±6.82 and mean weight (in kilograms) was 73±10.74.

Table: -3 Baseline variables

The mean BMI (kg/m²)of  Group 1 was  24.36±3.25 and  mean BSA (m²) was 1.86±0.14.

Table: - 4 Time Domain Analysis in Group 1

The mean RR(s) in Group 1 was 0.78±0.13 s. The STD (SDNN)(s) in Group 1 was 0.05±0.03 s. The mean Heart Rate (beats/min) in Group 1 was 75.49±8.38/min. The RMSSD (ms) in Group 1 was 34.49±21.28 ms. The NN50 (count) in Group 1 was 11.65±8.74. The pNN50 (%) in Group 1 was 7.88±5.92%.

Table: - 5 Frequency Domain Analysis in Group 1

The VLF peak (Hz) in Group 1 was 0.02 ± 0.00 Hz. The LF peak (Hz) in Group 1 was 0.09±0.07Hz. HF peak (Hz) in Group 1 was 0.16±0.01 Hz. VLF power (ms²) in Group 1 was 7.66±10.26 ms². LF power (ms²) in Group 1 was 26.34±52.93 ms². HF power (ms²) in Group 1 was 9.62±16.67 ms². VLF power (%) in Group 1 was 24.94±15.30%. LF power (%) in Group 1 was 50.68 ± 13.72 %. HF power (%) in Group 1 was 24.35 ± 11.84 %. LF/HF ratio in Group 1 was 2.55±1.32.  LF power (nu) in Group 1 was 67.63±12.34 nu. HF power (nu) in Group 1 was 32.36±12.34 nu.

Mobile phone (MP) technology has grown significantly over the past decade and has become an essential part of our everyday lives. However, due to the widespread exposure to electromagnetic fields (EMF) from mobile communication systems, there may be some negative effects on health in the living environment. It is possible that EMF generated by MPs may have an influence on the autonomic nervous system (ANS), which modulates the function of the circulatory system.[9-10] Today, heart problems have become the most frequent cause of death in the western world. The number of sudden cardiac deaths in the United States is estimated between 200.000 and 500.000 per year, with 50% to 70% being due to mechanisms related to arrhythmias.[11] We studied mean RR, STD(SDNN), mean HR, RMSSD, NN50, pNN50 in Time Domain Analysis and VLF peak, LF peak, HF peak, VLF power, LF power, HF power, VLF power%, LF power%, HF power%, LF/HF ratio, LF power nu and HF power nu in Frequency Domain Analysis[12]. A detailed comparison between our study and those derived from various other well documented studies is done in following paragraphs. The present study was done to see effect of mobile phone usage on cardiac autonomic function parameters in healthy males by means of heart rate variability. It was conducted in 150 healthy young males in age group of 18-21 years. The subjects were divided into three groups according to their duration of mobile phone use [<30 min/day] [13-14]. The comparison of anthropometric parameters in Group 1. In this study, the mean age in group 1 was (18.60±0.75 years). There was no statistically significantly difference in age. The mean height in Group 1 was (173.08±6.82 cms). There was no statistically significant difference in height. The mean weight in Group 1 was (73±10.74 Kgs). There was no statistically significant difference in weight. The mean BMI in Group 1 was (24.36±3.25 kg/m2). There was no statistically significant difference in BMI. The mean BSA in Group 1 was (1.86±0.14 m2). There was no statistically significant difference in BSA. In this study, the mean age in group 1 was (18.60±0.75 years). There was no statistically significantly difference in age.

The results of the present study demonstrate that a long-term duration of MP use influence HRV and change the autonomic balance in favor of an increased sympathetic tone. An increase in the sympathetic tone concomitant with a decrease in the parasympathetic tone measured indirectly by analysis of HRV was observed in long-term MP users. EMF generated by the long-term use of MPs was the tentative explanation for the detrimental changes in HRV.

1. http://en.wikipedia.org/wiki/Mobile_phone_radiation_and_health extracted on 30.08.2009s.
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