Anthropometric data of freediver volunteersa
| Participant | Longest Breath-Hold until MRI (min) | Start of Sport (yr before MRI) | Estimated Breath-Holds >2 min 30 s per Session | Sessions per Month | Estimated Cumulative Lifetime Breath-Holds >2 min 30 s | Age (yr) |
|---|---|---|---|---|---|---|
| 1 | 10.6 | 11.3 | 30 | 0.4 | 1632 | 31 |
| 2 | 5.5 | 1.5 | 7 | 8 | 1008 | 36 |
| 3 | 5.4 | 2.0 | 1 | 1 | 24 | 20 |
| 4 | 5.4 | 11.0 | ~0 | 8 | 4 | 33 |
| 5 | 5.0 | 2.0 | 0.125 | 8 | 24 | 40 |
| 6 | 5.5 | 10.0 | ~0 | 4 | 4 | 38 |
| 7 | 5.0 | 8.0 | 5 | 8 | 3840 | 61 |
| 8 | 5.5 | 1.5 | 0.5 | 4 | 36 | 34 |
| 9 | 5.0 | 7.0 | 6 | 16 | 8064 | 47 |
| 10 | 6.2 | 9.0 | 6 | 7 | 4536 | 26 |
| 11 | 5.3 | 27.5 | 15 | 16 | 79,200 | 64 |
| 12 | 6.5 | 10.2 | 12 | 28 | 11,712 | 51 |
| 13 | 5.5 | 11.3 | 10 | 16 | 21,760 | 35 |
| 14 | 5.5 | 1.6 | 18 | 10 | 3420 | 32 |
| 15 | 5.0 | 5.0 | 0.083 | 4 | 20 | 50 |
| Median | 5.5 | 8.0 | 6 | 8 | 2526 | 36.0 |
| 95% CI | 5.3–5.5 | 2.0–11.0 | 0.14–12.0 | 4.0–9.96 | 30–6300 | 32–50 |
| Minimum | 5.0 | 1.5 | 0 | 0.41 | 4 | 20 |
| Maximum | 10.6 | 27.5 | 30 | 28 | 79,200 | 64 |
↵a Participants were interviewed concerning the duration (start of sport) and intensity (freediving sessions per month) and the estimated frequency of breath-holding for >2 minutes and 30 seconds per session. The latter could be near zero in freedivers specializing in short high-frequency breath-holds. Some participants breath-held for >2 minutes and 30 seconds only as a qualification for this study; hence, their cumulative lifetime breath-holds of >2 minutes and 30 seconds before MRI were 4, while others very frequently underwent prolonged breath-hold.