Evidence map›Paper›PMID 41695456›Full record

ArticleEvolutionary human sciences2026

Infant's thermal balance and the evolution of the human breast - a proof-of-concept study.

Tiina Kuvaja, Tiina Väre, Sirkka Rissanen, Hannu Rintamäki, Petri Lehenkari, Juho-Antti Junno

Abstract read
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Article in Evolutionary human sciences, 2026. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Not yet cited in PubMed.

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0citing papers in PubMed
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1 · What the graph read from it

What it found

Each row is one number read from the abstract, on the scale the paper reported it, with its interval. Left of the dashed line favours the treatment, right favours the comparator. Under each row is the sentence it came from. New to these charts? A ten-minute tutorial.

The abstract states no effect estimate the extractor could read, or names no intervention and outcome on the map, so this paper lights no cell and moves no belief. It is still indexed, cited and linked below.

2 · The registry

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3 · Its place in the literature

Who cites it

0 citing papers in PubMed.

No citing paper in PubMed yet.

4 · The record

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PubMed lists nothing against this paper. Absence here is not a guarantee, only a check that was made.

5 · Who and what money

Authors and funding

6 authors.

Tiina KuvajaArchaelogy, Faculty of Humanities, University of Oulu, Oulu, Finland.
Tiina VäreArchaelogy, Faculty of Humanities, University of Oulu, Oulu, Finland.
Sirkka RissanenFinnish Institute of Occupational Health, Oulu, Finland.
Hannu RintamäkiFinnish Institute of Occupational Health, Oulu, Finland.
Petri LehenkariDepartment of Anatomy, Medical Research Center Oulu, University of Oulu and Oulu University Hospital, Oulu, Finland.
Juho-Antti JunnoArchaelogy, Faculty of Humanities, University of Oulu, Oulu, Finland.ORCID https://orcid.org/0000-0003-0481-6958

Funding

No grant is acknowledged in the PubMed record.

6 · The paper itself

Abstract

The distinct size and shape of breasts in women is a uniquely human trait. This trait has no conclusive explanation as it is not a requirement for milk production. Additionally, breasts are already enlarged at puberty, which is usually long before the first pregnancy. We hypothesized that the perennially enlarged human breasts were potentially developed to support infant's thermal balance by providing increased warming surface in skin-to-skin contact. To test the hypothesis, we measured breast surface temperature to explore their heating capacity and resilience to temperature changes in an environmental conditions laboratory. Volunteers, divided in groups of nursing women, non-nursing women, and men, were exposed to three temperatures: 32°C, 27°C, and 18°C. The exposure time in each temperature was 20 min. The changes in breast surface temperature were recorded by thermal imaging camera. Data were analysed using Kruskal-Wallis tests. Breastfeeding women had overall higher mammary surface temperature compared to other groups. Furthermore, nursing women had distinct resilience against cooling environment: they lost the average of 2.5°C of their mammary surface temperature, whereas other study groups lost 4.3°C and 4.7°C of surface temperature, respectively. This proof-of -concept study clearly indicated the potential of the nursing women's breasts to support infant's thermal balance.

Indexed as

breast evolutionlactationmammary tissuethermoregulation

Identifiers

PMID41695456
PMCPMC12895438

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Read under generation 80e0d062 · epoch 390. Bibliography from PubMed, PubMed Central and OpenAlex; grants from NIH RePORTER; trial links from ClinicalTrials.gov; estimates, votes and beliefs from the OpenQuestion graph.