Joordens and Schagatay put breath-hold diving before running in the origin of human endurance
The forthcoming PaleoAnthropology paper argues that pacing oxygen across repeated shallow dives built the cardiorespiratory stamina later used for running, with a two-hour recording of one Ama diver's shift supplying the measurements.
The Scientist · Science desk
What happened
- Josephine Joordens and Erika Schagatay propose a "dive first, run later" hypothesis for human aerobic endurance, built from comparative physiology, anatomy, paleoecology and paleoanthropology, in a study to be published in PaleoAnthropology.
- They define endurance diving as repeated dives with short breathing pauses at a regular pace, the working pattern of modern freediving populations such as the Japanese Ama and the Sama-Bajau.
- A two-hour time-depth recording of one Ama diver's shift logged 50 dives to depths of around 8 to 10 meters, with 45 percent of the time spent underwater.
- The pair do not dismiss the endurance running hypothesis, arguing instead that the origin of human stamina cannot be understood from land-based foraging alone.
- The study claims to be the first to place the physiological overlap between breath-hold diving ability and high-altitude tolerance in a human evolutionary context.
Why it matters
- What it limits constraint Physiology measured in living divers cannot rank diving ahead of running in time. Fossils and reconstructed near-shore habitats have to settle the sequence in the hypothesis.
- What's now possible capability Because the ancestral trait proposed here is oxygen pacing under repeated hypoxia, it can be instrumented in living freedivers, so the argument has an experimental arm as well as a fossil one.
- Who has to decide decision Anyone who teaches pursuit hunting as the textbook account of human stamina now has to decide whether to present a diving-first sequence beside it, and say which parts of the running case they still treat as sufficient.
- What it sets up precedent With a named alternative in a journal, the next round of papers on hominin locomotion is likely to address diving as well as running.
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A diver who is at the surface for only half of a working period has to take in twice as much air while she can, and has to hold effort below the point where lactate accumulates [10]. Sustaining that takes respiratory and cardiovascular capacity plus the ability to pace breathing and breath-holding [10]. Joordens and Schagatay argue that this pacing ability could have started the evolution of the cardiorespiratory stamina that long-distance running requires [11]. "When studying the origin of human endurance and the evolutionary history of the Homo sapiens lineage, it is imperative to take not only endurance running, but also endurance diving for food, into account," they argue [2].
The measurements behind that pattern come from one working shift. Fifty dives in 120 minutes is one dive every 2.4 minutes [16]; 45 percent of two hours is 54 minutes underwater [17]; spread across the dives, that is roughly 65 seconds below the surface each time against about 79 seconds on it [18]. "This diving method enables individuals to work underwater for hours each day while holding their breath," said Schagatay, a professor of animal physiology whose work covers human performance in hypoxic environments [7]. One trace from one diver cannot show how a population of them works. What it does show is that the pattern is sustainable in a trained modern freediver.
High bone mass appears in many hominin fossils, and the authors reinterpret it as an adaptation to diving in shallow water [12]. The fossil record bears on that claim directly.
The comparison most open to testing is the altitude one. Breath-hold diving and high-altitude living both impose low oxygen; the diving response conserves oxygen during a dive, and a trait such as a large spleen can raise blood oxygen content in both settings [15].
Bramble and Lieberman's 2004 hypothesis derived long legs, effective cooling mechanisms and increased aerobic capacity from hunting terrestrial prey over long distances [3]. Humans are unusual among primates in being capable endurance runners as well as strong long-distance swimmers and skilled breath-hold divers [14]. "Our study provides a balanced land-and-water perspective on human evolution," said Joordens, a professor of hominin paleoecology and evolution [8]. A synthesis of existing comparative evidence does not weigh the energetic returns of the two activities against each other. What it can do is propose a sequence. "A combination of land-based foraging and foraging in water close to the shore by shallow diving could have shaped the multifaceted humans we are today," she said [9].
What to watch
- Publication in PaleoAnthropology, and whether the full paper lists skeletal predictions beyond high bone mass that could falsify the diving sequence.
- A direct comparison of diving response and spleen data between freediving populations and highland populations, which the study frames as physiologically parallel.
- Published responses from researchers working on the endurance running hypothesis, including whether they accept the incompleteness claim.
Clarity's read
What the record supports and how the coverage leans. The claims behind it follow.
Reality
- Evidence36
- Adoption
- Not scored
- Hype gap+22
- Incentives58
- Confidence55
Claim ledger
Ranked by verification strength, evidence, and original report placement.
- [1]
Researchers Josephine Joordens and Erika Schagatay propose a new "dive first, run later" hypothesis, drawing on comparative physiology, anatomy, paleoecology and paleoanthropology to address why humans evolved exceptional aerobic endurance.
- [2]
"When studying the origin of human endurance and the evolutionary history of the Homo sapiens lineage, it is imperative to take not only endurance running, but also endurance diving for food, into account," the researchers argue.
- [3]
The endurance running hypothesis, first put forward by Bramble and Lieberman in 2004, holds that characteristics such as long legs, effective cooling mechanisms and increased aerobic capacity evolved as a result of early humans hunting terrestrial prey by pursuing animals over long distances; it remains one of the main textbook explanations.
- [4]
Joordens and Schagatay do not dismiss the endurance running hypothesis outright; they argue that it may be incomplete and that the origin of human stamina cannot be understood from land-based foraging alone.
- [5]
The study describes "endurance diving" as making repeated dives with short breathing pauses at a regular pace to minimize recovery time at the surface and maximize time spent underwater.
- [6]
A 2-hour time-depth recording of an Ama diver's working shift shows 50 dives to depths of around 8-10 meters, with 45% of the time spent underwater.
- [7]
"This diving method enables individuals to work underwater for hours each day while holding their breath," says Schagatay, a professor of animal physiology and a specialist in human performance in hypoxic environments.
- [8]
"Our study provides a balanced land-and-water perspective on human evolution," says Joordens, a professor of hominin paleoecology and evolution.
- [9]
"A combination of land-based foraging and foraging in water close to the shore by shallow diving could have shaped the multifaceted humans we are today," says Joordens.
- [10]
Endurance diving requires enhanced respiratory and cardiovascular capacity and the ability to pace breathing and breath-holding efficiently; when a person is breathing only half the time, they must breathe twice as much when they can, and avoiding the buildup of lactate is essential.
- [11]
The researchers argue that the diving-related ability to pace effort and manage oxygen could have started the evolution of the cardiorespiratory stamina required for long-distance running.
- [12]
The study revisits high bone mass, a notable feature of many hominin fossils, as an adaptation to diving in shallow water.
- [13]
Modern populations of freedivers, such as the Ama and the Sama-Bajau, dive repeatedly for hours to hunt fish and gather shellfish and other aquatic resources; Japanese Ama divers gather abalone and turbo shells by repeatedly diving to shallow depths.
- [14]
Humans are unusual among primates: capable endurance runners, strong long-distance swimmers and skilled breath-hold divers.
- [15]
Breath-hold diving and high-altitude exposure both involve hypoxic conditions; an effective diving response helps conserve oxygen during dives, while traits such as a large spleen can increase blood oxygen content in both diving and high-altitude environments.
- [16]
The recorded shift averages one dive every 2.4 minutes.
- [17]
45% of a two-hour shift is 54 minutes spent underwater.
- [18]
Across 50 dives, the average time submerged is about 65 seconds per dive, leaving about 79 seconds per cycle at the surface.
- [19]
The study will be published in PaleoAnthropology.
- [20]
The study is described as the first to place these physiological similarities between breath-hold diving ability and high-altitude tolerance in a human evolutionary context.
Sources
2 independent publishers whose own reporting we read for this story.
- discovermagazine.comDiving Like Sea Otters May Have Helped Our Ancestors Build the Stamina to Run
1 article · September 17, 2026
- phys.orgEndurance running or endurance diving—which came first?
1 article · September 17, 2026
Topics and entities
Topics
- Human Evolution
- Paleoanthropology
- Hypoxia physiology
- Endurance physiology
- Breath-hold diving
Entities
- Endurance running hypothesis
- Dive first, run later hypothesis
- Josephine Joordens
- PaleoAnthropology
- Homo erectus