With cell-phones confirming dinner reservations, Facebook giving us new friends, and laptops as light as air, technology may seem nothing but valuable. But hold on iPhone 5-noise-cancelling-bluetooth users— technology can also be a huge hazard to our health. Here are 19 things to look out for before plugging in.

1. Smartphone stress. Feeling a bit anxious? Scientists have found an association between smartphones and stress, as people constantly check messages and alerts (why hasn’t he/she texted me back?!). So take a break! Turn phones to silent or plan to check it only every few hours.

2. Acne caused by cell phones. Scrubbing down before bed may not be enough to keep pesky acne at bay. Cell phones can be covered in bacteria, causing oils to collect when placed against the face. The result? Unwanted pimples on cheeks and chins! (And unfortunately, there’s no app to help.) Try talking on speakerphone or use a headset to keep phones away from the face.

3. BlackBerry thumb. Yes, blackberry thumb is actually a thing. That magic little scrolling ball BBMers worship can actually cause stress injuries to the thumb, which can cause tendonitis. And while a thumb injury may derail texting habits, it can be quite painful (especially during a thumb war). The solution? Take a break from the BlackBerry (or buy a different phone!).

4. Radiation from cell phones. Cell phonesemit some radiation that can be absorbed by the user, but research has yet to prove the amount can be harmfulThe problem with cell phones…or maybe not. Yung, W.K. Neuro-Oncology,2010 Nov;12(11):1087.. However, it has become a slight concern as more and more people are using cellular devices. (Even two year-olds.)

5. Cell phone sickness. It’s not just the gym that’s full of germs. Researchers have found mobile phones can be contaminated with various types of microorganisms that could lead to infectionAre we aware how contaminated our mobile phones with nosocomial pathogens? Fatma, U, Saban, E, Ahmet, D, et al. Department of Anesthesiology and Reanimation, Faculty of Medicine, Ondokuz Mayis University, Samsun, Turkey. Annals of Clinical Microbiology and Antimicrobials, 2009; 8: 7.. Unfortunately, it’s not as easy as tossing phones into the washing machine (kids, don’t try this at home), but they are easy enough to clean by hand!

6. Cell phones and car accidents. Chatting on the phone while driving is more than just distracting— it can actually reduce activity in the brain and draw our focus away from the road. So ditch the phone and keep both hands on the wheel! And don’t even think about texting. Oprah would so not approve!

7. Allergies and cell phones. Pollen, dog fur, peanuts and… cell phones? Yep, when phones come into contact with faces, a facial allergic reaction, a.k.a. dermatitis, can surfaceCell phone allergic contact dermatitis: case report and review. Raipara, A, Feldman, S.R. Wake Forest University Department of Dermatology, Winston-Salem, North Carolina. Dermatology Online Journal, 2010 Jun 15;16(6):9.. Just another reason to put the phone on speaker, stick to texting, or (gasp)— speak to someone in person.

8. Crazy phones. Okay, so this may be a bit sensationalist, but in one study, 68 percent of cell-phone users experience “phantom vibrations,” or thinking they felt a phone vibrate in a pocket or purse, only to realize there was nothing therePhantom vibration syndrome among medical staff: a cross sectional survey. Rothberg, M.B., Arora, A, Hermann, J, et al. Division of General Medicine, Baystate Medical Center, Springfield, MA. British Medical Journal, 2010 Dec 15;341:c6914. Unfortunately, there’s no remedy for this one.

9. Computers causing wrist pain. Carpel tunnel, one cause of wrist pain, can occur from excessive typing. So ease up on the tweets and take a break from the computer— or at least keep the keyboard low enough so the wrist doesn’t bend upwards.

10. Computers causing back and neck pain. It doesn’t stop at the wrist. A recent study found leaning in to read the small print on a tablet screen can strain the neckTouch-screen tablet user configurations and case-supported tilt affect head and neck flexion angles. Young, J.G., Trudeau, M., Odell, D. et al. Department of Environmental Health, Harvard School of Public Health, Boston, MA. Work 2012;41(1):81-91.. And other research suggests hunching over that laptop (or desktop!) can cause pain in the neck and backThe association between children’s computer use and musculoskeletal discomfort. Jacobs, K, Baker, N.A. Boston University, Sargent College of Health and Rehabilitation Science, Boston, MA. Works, 2002;18(3):221-6.. Need a simple solution? Place the tablet on a table, in a case that holds it upright. When using a laptop or desktop, use a standing desk (or build a makeshift one)!

11. Decreased sperm countfrom WiFi. Sorry dudes— better keep that laptop off the lap so those sperm keep swimmin’. A recent study found that radiation from Wi-Fi can kill sperm if the computer is too close to the crotchUse of laptop computers connected to internet through Wi-Fi decreases human sperm motility and increases sperm DNA fragmentation. Avendano, C, Mata, A, Sanchez, Sarmeinto C.A., et al. Nascentis Medicina Reproductiva, Córdoba, Argentina. Fertility and Sterility, 2012 Jan;97(1):39-45.e2. Epub 2011 Nov 23..

12. Laptop burns. Pyro’s aren’t the only ones increasing their risk of getting burned. If dying sperm isn’t an issue, keeping the computer off that lap will at least prevent the risk of second-degree burns laptops have been known to causeThigh burn associated with laptop computer use. Paulius, K, Napoles, P, Maquina, P. Department of Plastic Surgery, University of Illinois Medical Center at Chicago, Chicago, Illinois. Journal of Burn Care & Research, 2008 Sep-Oct;29(5):842-4..

13. Laptop headaches. Hangover headaches are so last year. Straining eyes by staring at the computer screen for too long can cause headaches and blurred visionA controlled study of visual symptoms and eye strain factors in chronic headache. Vincent, A.J., Spierings, E.L., Messinger, H.B. Headache, 1989 Sep;29(8):523-7.. Luckily, you can now listen to many Greatist articles, so close those eyes and listen away! (Just finish reading this one article first.)

14. Sleeping problems from laptops. Counting sheep ain’t cutting it? It may be from cuddling up with that laptop in bed. The artificial light from screens can suppress the release of melatonin, which helps us sleepEffect of Light on Human Circadian Physiology. Duffy, J.F., Czeisler, C.A. Journal of Clinical Sleep Medicine, 2009 Jun;4(2):165-177.. Swap the computer for a book before hitting the hay and hopefully those zzz’s will come a bit more easily.

15. Decreased attention span from using Facebook. Sure, it gives us virtual friends. But scientists have also suggested Facebook may affect brain activity (damn that constantly moving news feed!), potentially leading to attention-deficient disorder. So reduce the time spent Facebook stalking former middle school crushes and hang out with real friends instead.

16. The Internet causing anxiety. Over 60 percent of Americans turn to The Internet to help diagnose their aches and pains. But WebMD is no personal doctor, and relying on Dr. Google may lead to cyberchondria— excessive health anxiety caused by online searches. If something’s worrisome, try making the trek to a professional instead of the computer.

17. Headphone use leading to accidents. In the past eight years, 116 pedestrians have died while wearing headphones. Don’t just turn down the volume; to really hear those trains, planes, and automobiles, unplug completely.

18. Hearing loss from headphones. Listen up and turn the music down. Blasting those tunes through our headphones can lead to hearing impairment, so keep the noise at a safe listening level— around 80 decibelsEvaluation of noise-induced hearing loss in young people using a web-based survey technique. Chung, J.H., Des Roches, C.M., Meunier, J, et al. Department of Otolaryngology, Pediatric Otolaryngology Service, Boston, Massachusetts 02114. Pediatrics, 2005 Apr;115(4):861-7..

19. Death from… social networking? Okay, it’s their words, not ours. But some have suggested that spending all day on Facebook, Twitter, Tumblr (and so on) can have negative biological effects on the body as people substitute real social interaction with online interaction. So skip tweets, messaging, and commenting, and hang out with people in the real world!

Originally posted January 2012. Updated May 2012.