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Size matters: spleen and lung volumes predict performance in human apneic divers.

Schagatay E, Richardson MX, Lodin-Sundström A - Front Physiol (2012)

Bottom Line: Spleen volume did not correlate with subject height or weight, but was positively correlated with competition score (r = 0.57; P < 0.05).VC was also greater in the high-scorers, at 7.9 (0.36) L as compared to 6.7 (0.19) L in the low scorers (P < 0.01).We conclude that both spleen- and lung volume predict apnea performance in elite divers.

View Article: PubMed Central - PubMed

Affiliation: Department of Engineering and Sustainable Development, and Swedish Winter Sports Research Centre, Mid Sweden University Östersund, Sweden.

ABSTRACT
Humans share with seals the ability to contract the spleen and increase circulating hematocrit, which may improve apneic performance by enhancing gas storage. Seals have large spleens and while human spleen size is small in comparison, it shows great individual variation. Unlike many marine mammals, human divers rely to a great extent on lung oxygen stores, but the impact of lung volume on competitive apnea performance has never been determined. We studied if spleen- and lung size correlated with performance in elite apnea divers. Volunteers were 14 male apnea world championship participants, with a mean (SE) of 5.8 (1.2) years of previous apnea training. Spleen volume was calculated from spleen length, width, and thickness measured via ultrasound during rest, and vital capacity via spirometry. Accumulated competition scores from dives of maximal depth, time, and distance were compared to anthropometric measurements and training data. Mean (SE) diving performance was 75 (4) m for constant weight depth, 5 min 53 (39) s for static apnea and 139 (13) m for dynamic apnea distance. Subjects' mean height was 184 (2) cm, weight 82 (3) kg, vital capacity (VC) 7.3 (0.3) L and spleen volume 336 (32) mL. Spleen volume did not correlate with subject height or weight, but was positively correlated with competition score (r = 0.57; P < 0.05). Total competition score was also positively correlated with VC (r = 0.54; P < 0.05). The three highest scoring divers had the greatest spleen volumes, averaging 538 (53) mL, while the three lowest-scoring divers had a volume of 270 (71) mL (P < 0.01). VC was also greater in the high-scorers, at 7.9 (0.36) L as compared to 6.7 (0.19) L in the low scorers (P < 0.01). Spleen volume was reduced to half after 2 min of apnea in the highest scoring divers, and the estimated resting apnea time gain from the difference between high and low scorers was 15 s for spleen volume and 60 s for VC. We conclude that both spleen- and lung volume predict apnea performance in elite divers.

No MeSH data available.


Related in: MedlinePlus

Minute to minute mean (SD) spleen volume (SV) before and after 2 min apnea in the three highest scoring divers. Significance at P < 0.05 is indicated by *.
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Figure 3: Minute to minute mean (SD) spleen volume (SV) before and after 2 min apnea in the three highest scoring divers. Significance at P < 0.05 is indicated by *.

Mentions: When the highest scoring subjects performed a 2 min apnea, their mean spleen volume decreased by 260 mL (P < 0.05; Figure 3). Based on the spleen volume reduction observed, the splenic blood contribution to apneic duration in high performing divers was estimated. Spleen blood contains at least double the normal hematocrit (Laub et al., 1993; Stewart and McKenzie, 2002) and with 260 mL of spleen blood being added to the circulation, equivalent in Hb content to at least 500 mL of whole blood, it could bind another 100 mL of O2. Estimating during resting apnea, based on RMR measurements via indirect calorimetry (Byrne et al., 2005), 2.67 mL O2/kg/min, as approximately 200 mL O2/min, the extra O2 stored in the three top-scoring divers would last for 30 s. The smaller spleens in the three lowest-scoring divers would, assuming a similar 50% spleen volume reduction, contribute extra O2 lasting approximately 15 s. Thus, the three best divers could extend apneic duration by 15 s in comparison to the three lowest-scoring divers, due to the extra O2 storage capacity resulting from the Hb expelled by their larger spleens.


Size matters: spleen and lung volumes predict performance in human apneic divers.

Schagatay E, Richardson MX, Lodin-Sundström A - Front Physiol (2012)

Minute to minute mean (SD) spleen volume (SV) before and after 2 min apnea in the three highest scoring divers. Significance at P < 0.05 is indicated by *.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3376424&req=5

Figure 3: Minute to minute mean (SD) spleen volume (SV) before and after 2 min apnea in the three highest scoring divers. Significance at P < 0.05 is indicated by *.
Mentions: When the highest scoring subjects performed a 2 min apnea, their mean spleen volume decreased by 260 mL (P < 0.05; Figure 3). Based on the spleen volume reduction observed, the splenic blood contribution to apneic duration in high performing divers was estimated. Spleen blood contains at least double the normal hematocrit (Laub et al., 1993; Stewart and McKenzie, 2002) and with 260 mL of spleen blood being added to the circulation, equivalent in Hb content to at least 500 mL of whole blood, it could bind another 100 mL of O2. Estimating during resting apnea, based on RMR measurements via indirect calorimetry (Byrne et al., 2005), 2.67 mL O2/kg/min, as approximately 200 mL O2/min, the extra O2 stored in the three top-scoring divers would last for 30 s. The smaller spleens in the three lowest-scoring divers would, assuming a similar 50% spleen volume reduction, contribute extra O2 lasting approximately 15 s. Thus, the three best divers could extend apneic duration by 15 s in comparison to the three lowest-scoring divers, due to the extra O2 storage capacity resulting from the Hb expelled by their larger spleens.

Bottom Line: Spleen volume did not correlate with subject height or weight, but was positively correlated with competition score (r = 0.57; P < 0.05).VC was also greater in the high-scorers, at 7.9 (0.36) L as compared to 6.7 (0.19) L in the low scorers (P < 0.01).We conclude that both spleen- and lung volume predict apnea performance in elite divers.

View Article: PubMed Central - PubMed

Affiliation: Department of Engineering and Sustainable Development, and Swedish Winter Sports Research Centre, Mid Sweden University Östersund, Sweden.

ABSTRACT
Humans share with seals the ability to contract the spleen and increase circulating hematocrit, which may improve apneic performance by enhancing gas storage. Seals have large spleens and while human spleen size is small in comparison, it shows great individual variation. Unlike many marine mammals, human divers rely to a great extent on lung oxygen stores, but the impact of lung volume on competitive apnea performance has never been determined. We studied if spleen- and lung size correlated with performance in elite apnea divers. Volunteers were 14 male apnea world championship participants, with a mean (SE) of 5.8 (1.2) years of previous apnea training. Spleen volume was calculated from spleen length, width, and thickness measured via ultrasound during rest, and vital capacity via spirometry. Accumulated competition scores from dives of maximal depth, time, and distance were compared to anthropometric measurements and training data. Mean (SE) diving performance was 75 (4) m for constant weight depth, 5 min 53 (39) s for static apnea and 139 (13) m for dynamic apnea distance. Subjects' mean height was 184 (2) cm, weight 82 (3) kg, vital capacity (VC) 7.3 (0.3) L and spleen volume 336 (32) mL. Spleen volume did not correlate with subject height or weight, but was positively correlated with competition score (r = 0.57; P < 0.05). Total competition score was also positively correlated with VC (r = 0.54; P < 0.05). The three highest scoring divers had the greatest spleen volumes, averaging 538 (53) mL, while the three lowest-scoring divers had a volume of 270 (71) mL (P < 0.01). VC was also greater in the high-scorers, at 7.9 (0.36) L as compared to 6.7 (0.19) L in the low scorers (P < 0.01). Spleen volume was reduced to half after 2 min of apnea in the highest scoring divers, and the estimated resting apnea time gain from the difference between high and low scorers was 15 s for spleen volume and 60 s for VC. We conclude that both spleen- and lung volume predict apnea performance in elite divers.

No MeSH data available.


Related in: MedlinePlus