Treatment with PEMF machines, TENS, Bemer, Papimi etc. How effective are they? How do they differ from the common sources of electromagnetic radiation around us?
Machines that produce artificial electromagnetic fields are now used worldwide by hospitals, physiotherapists, conventional and alternative practitioners to treat numerous diseases, from simple musculoskeletal problems to severe degenerative diseases .
Before the dominance of the pharmaceutical industry electromagnetic therapies had flourished. In 1884 it was estimated that in the US 10,000 physicians practiced electromagnetic therapies .
In recent years, treatments with electromagnetism resurfaced since their results are arguably stronger and safer than other conventional or alternative treatments and demonstrate how important the biological effect of radiation is on humans.
"All living cells and indeed whole living beings, no matter what genus or species, are dynamic coherent electrical systems utterly reliant on bioelectricity for life’s most basic metabolic processes. It turns out that most living things are fantastically sensitive to vanishingly small EMF exposures. Living cells interpret such exposures as part of our normal cellular activities (think heartbeats, brainwaves, cell division itself, etc.).” Blake Levit, author of "Electromagnetic Fields, A Consumer's Guide to the Issues and How to Protect Ourselves" 
There are various different electromagnetic field generator machines (PEMF = Pulsed Electromagnetic Fields, TENS = Transcutaneous Electrical Nerve Stimulation etc.), some of which use similar frequencies and waveforms to sources of electromagnetic pollution.
Why is electrosmog dangerous and machines that produce electromagnetic radiation beneficial?
Dr. Martin Planck, professor at Columbia University and researcher in bioelectromagnetism explains that our cells react to artificial electromagnetic fields with the production of stress proteins, like they do with other environmental toxins .
Short term and periodic electromagnetic stress, even at high field intensity, submits us to a controlled state of stress, which can have an anabolic effect on the body (such as when working out).
Treatments with radiation are short, periodically applied (e.g. once a day) and usually utilize waves with continuously variable intensity and frequency.
For example a popular electromagnetic therapy aims to accelerate and increase cell proliferation in the case of bone fracture. It is applied topically, for a few minutes for a few sessions, and causes controlled cell proliferation.
In contrast, the continuous and simultaneous daily exposure to multiple sources of artificial radiation around us involves chronic stress proteins production which:
- Exhausts the immune system and leads to the appearance of autoimmune diseases such as rheumatoid arthritis, Crohn's Lyme, lupus, disease Crohn, multiple sclerosis, diabetes, etc. 
- Is associated with sleep problems, depression, headaches, gastric and skin problems, obesity, heart disease, asthma, infections, etc. 
In our opinion the above mechanism is a basic explanation of the connection of low and high frequency radiation with leukemia, cancer of the breast, skin, brain, testes and salivary gland, blood clots, diabetes, multiple sclerosis , miscarriages pregnancy, male infertility, Alzheimer, insomnia, neurotic disorders, depression etc.
 Naomi M. Schupak, Therapeutic uses of Pulsed Magnetic Field exposure: a review  James Oschman, Energy Medicine, The scientific basis  Camilla Rees- Magda Havas, Public Health SOS - The Shadow Side of the Wireless Revolution  Dr. Blank, Evidence For Stress Response, Bioinitiative Report  Stress Proteins in Medicine
http://www.researchandmarkets.com/reportinfo.asp?report_id=1310105&t=t&cat_id=[Six] Mayo Clinic, How Stress Affects Health,