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Home / Equine Research Bank / Animals (Basel) / What if Horses Were Humans? Comparing Rein Tension and Bit P...
Animals : an open access journal from MDPI2025; 15(20); 2989; doi: 10.3390/ani15202989

What if Horses Were Humans? Comparing Rein Tension and Bit Pressures to Human Pressure Pain Thresholds.

Abstract: Bit pressure and rein tension-induced mouth pain in horses have recently become a significant welfare concern, fueling debates within the equestrian community and beyond. Evidence indicates that bits can cause pain-related behaviors and even oral lesions. Although studying pressure-induced pain in animals is challenging, the similarities in the physiology of pain processing (nociception) across mammals suggest that it is reasonable to assume that pain perception in humans and horses is principally comparable. Therefore, we compared human pressure pain detection thresholds (PPDTs) to reported rein pressures in equestrian sports as reported in the scientific literature. Reported rein tensions (kPa) range from a minimum of 91.2-107.87 to a maximum of 1314.09-4285.51, while human PPDTs (in kPa) are 232.4 for the face, 445.3 for the hand, and 535.5 for the foot. These comparisons reveal that only the lowest reported bit pressures would be pain-free for humans. Average to maximum pressures would cause strong to severe pain sensations in humans. Furthermore, data on pressure pain-induced stimulus response functions suggest that bit pressures commonly encountered in equestrian sports could cause lesions in humans, making them unacceptable in human experimentation. In conclusion, bit pressures as reported in the scientific literature would cause significant pain if applied to humans, raising welfare concerns for horses.
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Publication Date: 2025-10-15 PubMed ID: 41153916PubMed Central: PMC12560900DOI: 10.3390/ani15202989Google Scholar: Lookup
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Summary

This research summary has been generated with artificial intelligence and may contain errors and omissions. Refer to the original study to confirm details provided. Submit correction.

Overview

  • This study compares the pressure exerted by horse bits and reins to the pressure pain thresholds experienced by humans to better understand the potential pain horses might feel during riding.
  • The findings suggest that many pressures applied by bits likely cause significant pain in horses, as equivalent pressures would be painful or damaging to humans.

Background and Motivation

  • Bit pressure and rein tension are known to cause discomfort and oral injuries in horses, leading to welfare concerns.
  • Due to the similarity in how mammals perceive pain (nociception), human pain thresholds can serve as a reference to estimate the pain horses might experience.
  • Studying pain directly in animals is difficult, so comparing to human pain thresholds helps interpret the impact of bit pressures on horse welfare.

Methods

  • The study collected data from scientific literature on rein tension measurements in horses, expressed in kilopascals (kPa).
  • Pressure pain detection thresholds (PPDTs) for humans were obtained for different body parts: face, hand, and foot, also in kPa.
  • The range of rein tensions reported in horse riding spanned from low values (~91.2-107.87 kPa) up to very high maximums (~1314.09-4285.51 kPa).
  • Human PPDTs were found to be 232.4 kPa (face), 445.3 kPa (hand), and 535.5 kPa (foot), which serve as benchmarks for pain detection.

Key Findings

  • Only the very lowest rein tensions were below the human pain detection threshold for the face, indicating minimal or no pain if humans were subjected to such pressures.
  • Most average to maximum rein tensions far exceeded the human PPDTs, implying that these pressures would cause moderate to severe pain sensations in humans.
  • Considering the relationship between pressure pain and tissue damage, common bit pressures in horse riding could cause oral lesions or injuries if applied to humans.
  • This suggests bit pressures currently used in equestrian sports are likely to cause significant pain and potentially tissue damage to horses.

Conclusions and Implications

  • The study highlights a significant welfare concern, as rein and bit pressures that cause pain in humans likely inflict pain on horses.
  • Current bit pressures, especially towards the higher range, raise ethical questions about their continued use in equestrian sports without mitigating pain and injury risks.
  • These insights should encourage the equestrian community to consider alternatives to bit use or methods that reduce rein tension to improve horse welfare.
  • Further research is needed to develop pain-free or low-pain methods to control horses while maintaining safety for both horse and rider.

Cite This Article

APA
Musial F, Weiss T. (2025). What if Horses Were Humans? Comparing Rein Tension and Bit Pressures to Human Pressure Pain Thresholds. Animals (Basel), 15(20), 2989. https://doi.org/10.3390/ani15202989

Publication

Animals : an open access journal from MDPI
ISSN: 2076-2615
NlmUniqueID: 101635614
Country: Switzerland
Language: English
Volume: 15
Issue: 20
PII: 2989

Researcher Affiliations

Musial, Frauke
  • National Research Center in Complementary and Alternative Medicine (NAFKAM), Department of Community Medicine, Faculty of Health Sciences, UiT The Arctic University of Norway, 9037 Tromsø, Norway.
Weiss, Thomas
  • Department of Clinical Psychology, Institute of Psychology, Friedrich Schiller University Jena, 07743 Jena, Germany.

Conflict of Interest Statement

The authors declare no conflicts of interest.

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Citations

This article has been cited 1 times.
  1. Fialová S, Kuřitková D, Sobotková E. Stress Responses in Dressage Horses: Insights from FEI Noseband Measurements Across National Competition Levels.. Animals (Basel) 2026 Feb 6;16(3).
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