Blood lactate accumulation during competitive freediving and synchronized swimming
Authors: Lara Rodríguez-Zamora, Harald K. Engan, Angelica Lodin-Sundström, Fanny Schagatay, Xavier Iglesias, Ferran A. Rodríguez, Erika Schagatay
DOI / Source: n/a
Date: 01 January 2018
Reading level: Beginner
Why This Matters for Freedivers
A lot of divers underestimate how “anaerobic” some disciplines really are—especially depth and no-fins. This paper shows that competitions can produce serious lactate levels (particularly CNF and CWT), which helps explain heavy legs, burning, and long recovery after a big attempt. It’s a useful reminder to train discipline-specifically and to respect recovery—because one maximal dive can be more like a hard race than a relaxing breath-hold.
Synopsis
Freediving is often described as an oxygen-saving sport, but competition freediving can also be brutally intense. When you work hard without breathing, your muscles eventually rely more on anaerobic energy, and a common marker of that is blood lactate. This study looked at what really happens in real competition—not in a lab—across multiple freediving disciplines and synchronized swimming events.
The researchers measured capillary blood lactate before and 3 minutes after competition performances, then calculated “net lactate accumulation” (NLA): the rise from pre to post. They collected data during three international freediving competitions (2010–2011) and the Spanish national synchronized swimming championships (2011). In total, they included elite freedivers and elite synchronized swimmers, and many athletes competed in more than one event.
They covered six freediving disciplines: - Static apnea (STA) - Dynamic with fins (DYN) - Dynamic no fins (DNF) - Constant weight (CWT) - Constant weight no fins (CNF) - Free immersion (FIM)
…and three synchronized swimming events: - Solo - Duet - Team
The big picture result
All nine disciplines showed measurable lactate rise. That means: apneic sports aren’t “purely aerobic,” even when they look smooth.
Which disciplines produced the most lactate
The highest average NLA was seen in CNF, followed closely by CWT, with synchronized swimming solo also surprisingly high. Static apnea had by far the lowest lactate rise (still not zero, but much smaller than the others).
Why CNF and CWT. The paper’s explanation is intuitive: - They use big muscle groups (legs, core, often arms too). - They include long continuous apnea—you can’t “pop up for air” mid-effort like you can stop early in a pool. - In depth diving, there may be phases where blood flow to working muscles is more restricted by the diving response, which can push muscles toward anaerobic metabolism—especially during the hard ascent.
Apnea time matters, but so does “type of work”
Across disciplines (excluding static), longer apnea duration was associated with higher NLA, but muscle mass and intensity mattered a lot. For example: - FIM involves long apnea, but mainly upper-body pulling (smaller muscle mass), and it showed lower lactate than the hardest finless depth work. - Synchronized swimming is intense whole-body work, but it includes short breathing breaks, which likely helps reduce overall lactate build-up compared with fully continuous breath-hold efforts.
Competition stress can show up before you even start
Pre-event lactate levels were often above “true rest,” especially in depth disciplines. The authors point out that competition nerves and warm-up demands can elevate stress hormones and muscle activation before the main attempt—meaning you may start your dive already a bit “revved up.”
Takeaways
This paper gives a reality check: freediving competitions—especially CNF and CWT—can push athletes beyond the “comfortable aerobic” zone into heavy anaerobic territory. That helps explain why some dives feel like a fight and why recovery can take longer than people expect, even if the dive looked calm from the surface.
Abstract
A number of competitive water sports are performed while breath-holding (apnea). Such performances put large demands on the anaerobic system, but the study of lactate accumulation in apneic sports is limited. The aim was to determine and compare net lactate accumulation (NLA) during competition events in six disciplines of competitive freediving and three disciplines of synchronized swimming. Capillary blood lactate concentration was measured before and three minutes after competition performances, and apneic duration and performance variables were recorded. NLA was observed in all nine disciplines. The highest mean NLA was found in constant weight no fins, followed by constant weight and synchronized swimming solo, while static apnea showed the lowest NLA compared with all other disciplines. Overall, sports involving apnea involved high levels of anaerobic activity, and NLA appeared to be influenced by both the type of work performed and apnea duration, with lower NLA in synchronized swimming likely due to intermittent breathing.