A woman pushes a baby in a forward-facing stroller, covered up to block the sun, in Tokyo’s Chuo Ward on July 29, 2025. (Mainichi/Tsutomu Kobayashi)
TOKYO — In the blazing summer heat, which kind of stroller is hotter for infants: the type that has the infant facing the pusher or the kind where they sit facing forward, looking outward?
Tetsuro Kita, a professor at Musashino Art University whose areas of expertise include health science, conducted an experiment to answer this question as hot weather continued to beat down on Japan’s capital.
Collecting temperature and UV data
The hour-long experiment took place on July 20 from 11:45 a.m. to 12:45 p.m. on a university campus in Tokyo. The wet bulb globe temperature, or WBGT, an indicator of heatstroke risk, was 33.3 at the start of the test — already in the danger zone of 31 or above, the highest on four levels.
Baby mannequins were placed in two strollers, both the same model, colored gray, with one facing the pusher and one facing forward, and temperatures around the head and feet, as well as UV information, were collected every 10 seconds.
The results showed that the average temperature around the head was 38.3 degrees Celsius (with a maximum of 42.1 C) for the pusher-facing type, which was 1.7 C higher than the forward-facing type’s average of 36.6 C (with a maximum of 39.5 C). Around the feet, the pusher-facing type averaged 36.3 C (with a maximum of 39.0 C), which was 1.0 C higher than the forward-facing type’s average of 35.3 C (with the maximum temperature hitting 37.3 C).
This file photo shows a pusher-facing stroller. (Getty Images)
Conversely, the cumulative UV exposure collected every 10 seconds was highest around the feet of the forward-facing type. The next highest level was seen around the feet of the pusher-facing type, followed by the head of the forward-facing type, with the least exposure around the head of the pusher-facing type.
The data confirmed that the pusher-facing type traps heat more easily, while the forward-facing type is more exposed to UV rays.
Kita commented, “For the pusher-facing type, efforts to reduce temperature and humidity, such as by using a fan, are necessary. For the forward-facing type, since the baby is exposed to more UV rays, measures such as applying sunscreen might be advisable.”
‘Refer to scientific knowledge’
In the experiment, the stroller was pushed continuously for an hour, but Kita noted, “It’s possible that if you proceeded slowly with stops, there could be a greater temperature difference between the pusher-facing and forward-facing types. Additionally, black or navy strollers would likely reach higher temperatures.”
He added, “This summer, we have frequently seen temperatures exceeding 40 C, and a record high was observed. Not only the heat but also UV rays are reaching levels people in Japan have never experienced before. As measures against the intense heat and UV rays, I would like guardians and others to refer to such scientific knowledge.”
(Japanese original by Reiko Noguchi, Digital News Group)
AloJapan.com