The Health Advantages of Incandescent Light vs. LED: A Scientific but Easy-to-Understand Breakdown

Modern lighting has largely shifted to LED (light-emitting diode) technology because it uses less energy and lasts longer. But while LEDs save electricity, they may negatively impact your health in ways that incandescent bulbs—the older, glowing filament kind—do not. The differences come down to the quality of light they produce and how that light interacts with the human body, especially our sleep-wake cycle, eyes, and cells.

Light Spectrum and Your Body Clock

Incandescent bulbs emit what’s known as full-spectrum light. This means they give off a smooth, continuous range of wavelengths—from visible light to infrared light, which we can’t see but can feel as warmth. This type of light closely mimics natural sunlight, especially during sunrise and sunset. That’s important, because your body’s internal clock (called your circadian rhythm) is regulated by light exposure.

LEDs, on the other hand, emit light in sharp peaks, mostly centered around the blue wavelength range (around 450 nanometers). This blue light strongly affects a special type of cell in your eyes called intrinsically photosensitive retinal ganglion cells (ipRGCs), which communicate with your brain’s sleep center. Too much blue light at night blocks melatonin—the hormone that makes you sleepy—and confuses your body into thinking it’s still daytime. That can lead to insomnia, fatigue, and long-term health effects like hormone imbalance and immune suppression.

Infrared Light and Mitochondrial Health

One thing LEDs completely lack is near-infrared (NIR) light—wavelengths just beyond what we can see. Incandescent bulbs produce a lot of it. NIR light has been shown to benefit the tiny engines inside your cells, called mitochondria. Through a process called photobiomodulation, NIR light helps mitochondria make more energy (ATP), reduce inflammation, and repair damaged tissue. So, incandescent bulbs may do more than just light a room—they might actually support healing and cellular health.

Flicker and Eye Strain

Another difference is how steady the light feels. Many LEDs flicker rapidly because of how they process electricity. Even though this flicker is too fast to see, your brain still senses it. For some people, it can cause eye strain, headaches, and even migraines. Incandescent bulbs don’t have this issue because they heat up a filament to produce light, which naturally stays steady and flicker-free.

Color Quality

Incandescent bulbs also have excellent color rendering—meaning colors under their light look natural and vibrant. They have a Color Rendering Index (CRI) of nearly 100, which is perfect. Many LEDs don’t score as high, especially when it comes to rich reds and skin tones. This can make your environment feel “off” or less comfortable without you even realizing why.

Final Thoughts

Incandescent bulbs may use more electricity, but they provide healthier, more natural light for your body and mind. Their full spectrum, infrared warmth, flicker-free glow, and high color quality make them a smart choice—especially in the evening hours when your body needs to relax and prepare for sleep. If you’re looking to improve your health through lighting, consider switching back to this timeless, human-friendly light source.