© 2025 WRVO Public Media
NPR News for Central New York
Play Live Radio
Next Up:
0:00
0:00
0:00 0:00
Available On Air Stations

Why you fight infection better in the daytime

A group of researchers primarily based at the University of Auckland in New Zealand set out to study neutrophils, a type of immune cell. After watching how fluorescent bacteria interacted with fluorescent neutrophils in transparent baby zebrafish, they found that the immune cells can indeed tell whether it's night or day.
matheesaengkaew
/
Getty Images
A group of researchers primarily based at the University of Auckland in New Zealand set out to study neutrophils, a type of immune cell. After watching how fluorescent bacteria interacted with fluorescent neutrophils in transparent baby zebrafish, they found that the immune cells can indeed tell whether it's night or day.

Depending on what time it is, your body responds differently to an injury or infection. During the day, you're likely to heal faster and fight infection better than at night.

Historically, scientists weren't entirely sure why.

That picture is starting to clear up thanks to a new study published last week in the journal Science Immunology. The research finds a missing piece of the puzzle in neutrophils, powerful immune cells that — despite living less than 24 hours — know the difference between day and night.


Got a question about how the body works? Let us know at shortwave@npr.org.

Listen to Short Wave on Spotify and Apple Podcasts.

Listen to every episode of Short Wave sponsor-free and support our work at NPR by signing up for Short Wave+ at plus.npr.org/shortwave.

This episode was produced by Berly McCoy and Jordan-Marie Smith, edited by Rebecca Ramirez and Christopher Intagliata and fact checked by Tyler Jones. Tiffany Vera Castro and Jimmy Keeley were the audio engineers.

Copyright 2025 NPR

Berly McCoy
Kimberly (Berly) McCoy (she/her) is an assistant producer for NPR's science podcast, Short Wave. The podcast tells stories about science and scientists, in all the forms they take.
Regina G. Barber
Regina G. Barber is Short Wave's Scientist in Residence. She contributes original reporting on STEM and guest hosts the show.
Ari Shapiro has been one of the hosts of All Things Considered, NPR's award-winning afternoon newsmagazine, since 2015. During his first two years on the program, listenership to All Things Considered grew at an unprecedented rate, with more people tuning in during a typical quarter-hour than any other program on the radio.
Jordan-Marie Smith
Jordan-Marie Smith is a producer with NPR's All Things Considered.
Christopher Intagliata is an editor at All Things Considered, where he writes news and edits interviews with politicians, musicians, restaurant owners, scientists and many of the other voices heard on the air.
Rebecca Ramirez (she/her) is the founding producer of NPR's daily science podcast, Short Wave. It's a meditation in how to be a Swiss Army Knife, in that it involves a little of everything — background research, finding and booking sources, interviewing guests, writing, cutting the tape, editing, scoring ... you get the idea.