NightStar FAQs - Is a pacemaker sensitive to the magnetic field that surrounds NightStar?

NightStar can affect a pacemaker's normal mode of operation. If the heart rate of a person with a pacemaker drops below a preset value (typically 85 beats per minute), an internal sensor monitoring the person's heart rate activates the pacemaker. A pacemaker will not send electrical signals to a person's heart unless their heart rate drops below the preset value.

In order to test whether a pacemaker is operating properly, a reed switch is built into the unit so that an external magnet held up to the patient's chest will close the reed switch and deactivate the internal heart rate sensor. When this happens, the pacemaker turns on and begins sending electrical signals to the heart at the preset value. Pacemakers are typically tested once or twice per year in specially equipped hospitals.

If a pacemaker begins sending signals to the heart at a rate of 85 beats per minute and the heart is already beating at a greater rate, an arrhythmia condition can be triggered. The possibility of this occurring is extremely rare; less than 1 percent of the people with pacemakers would be susceptible to this condition, and in many cases these susceptible people are already bedridden. A magnetic field with a strength of 90 gauss brought within 1.5 inches (40 cm) of a pacemaker will close the reed switch.

The magnet in NightStar has a surface field strength of over 5200 gauss. Consequently, in order to avoid turning on a pacemaker, NightStar should be held no closer than 2 inches (5 cm) to the chest. At this distance the field strength has dropped to approximately 30 gauss. A cautionary statement regarding the effect NightStar has on pacemakers is printed on the product packaging and instruction booklet.

(This information was obtained from a telephone conversation with one of the largest manufacturers of pacemakers in the United States).

More Frequently Asked Questions:

• Who invented the shake flashlight?

• How does the switch work?

• Why do NightStar, NightStar CS and NightStar RS require different amounts of shaking?

• What are the magnets made of and how are they magnetized?

• Can light output be made brighter by replacing the StarCore® LED with an incandescent bulb?

• Can batteries be included in the design to allow for a longer, brighter light output?

• Is a pacemaker sensitive to the magnetic field that surrounds NightStar?

• Can adding more LEDs increase the light output?

• How is the charging magnet reflected at either end of the flashlight?

• Why was a lens chosen for the output window?

• Why doesn't NightStar interfere with night vision?

• Why is the housing made from plastic?