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Richardson, Matt X.
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Publications (10 of 31) Show all publications
Engan, H., Schagatay, E., Lodin-Sundström, A., Richardson, M. & Beekvelt, M. (2013). Effects of two weeks of daily apnea training on diving response, spleen contraction, and erythropoiesis in novel subjects.. Scandinavian Journal of Medicine and Science in Sports, 23(3), 340-348
Open this publication in new window or tab >>Effects of two weeks of daily apnea training on diving response, spleen contraction, and erythropoiesis in novel subjects.
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2013 (English)In: Scandinavian Journal of Medicine and Science in Sports, ISSN 0905-7188, E-ISSN 1600-0838, Vol. 23, no 3, p. 340-348Article in journal (Refereed) Published
Abstract [en]

Three potentially protective responses to hypoxia have been reported to be enhanced in divers: (1) the diving response, (2) the blood-boosting spleen contraction, and (3) a long-term enhancement of hemoglobin concentration (Hb). Longitudinal studies, however, have been lacking except concerning the diving response. Ten untrained subjects followed a 2-week training program with 10 maximal effort apneas per day, with pre- and posttraining measurements during three maximal duration apneas, and an additional post-training series when the apneic duration was kept identical to that before training. Cardiorespiratory parameters and venous blood samples were collected across tests, and spleen diameters were measured via ultrasound imaging. Maximal apneic duration increased by 44 s (P < 0.05). Diving bradycardia developed 3 s earlier and was more pronounced after training (P < 0.05). Spleen contraction during apneas was similar during all tests. The arterial hemoglobin desaturation (SaO(2)) nadir after apnea was 84% pretraining and 89% after the duration-mimicked apneas post-training (P < 0.05), while it was 72% (P < 0.05) after maximal apneas post-training. Baseline Hb remained unchanged after training, but reticulocyte count increased by 15% (P < 0.05). We concluded that the attenuated SaO(2) decrease during mimic apneas was due mainly to the earlier and more pronounced diving bradycardia, as no enhancement of spleen contraction or Hb had occurred. Increased reticulocyte count suggests augmented erythropoiesis.

Keywords
Asphyxia; Bradycardia; Breath-hold training; Diving reflex; Reticulocytes; Spleen contraction
National Category
Physiology
Identifiers
urn:nbn:se:miun:diva-15819 (URN)10.1111/j.1600-0838.2011.01391.x (DOI)000318787900019 ()2-s2.0-84877660891 (Scopus ID)
Note

Article first published online: 29 SEP 2011

Available from: 2012-02-02 Created: 2012-02-02 Last updated: 2018-01-12Bibliographically approved
Richardson, M., Engan, H., Lodin-Sundström, A. & Schagatay, E. (2012). Effect of hypercapnia on spleen-related haemoglobin increase during apnea. Diving and Hyperbaric Medicine, 42(1), 4-9
Open this publication in new window or tab >>Effect of hypercapnia on spleen-related haemoglobin increase during apnea
2012 (English)In: Diving and Hyperbaric Medicine, ISSN 1833-3516, Vol. 42, no 1, p. 4-9Article in journal (Refereed) Published
Abstract [en]

BACKGROUND:

Splenic contraction associated with apnea causes increased haemoglobin concentration and haematocrit (Hct), an effect that may promote prolonged breath-holding. Hypoxia has been shown to augment this effect, but hypercapnic influences have not been investigated previously.

METHODS:

Eight non-divers performed three series of apneas on separate days after inspiration of oxygen with different carbon dioxide (CO₂) levels. Each series consisted of three apneas 2 minutes apart: one with pre-breathing of 5% CO₂ in oxygen (O₂, 'Hypercapnia'); one with pre-breathing of 100% O₂ ('Normocapnia'); and one with hyperventilation of 100% O₂ ('Hypocapnia'). The apnea durations were repeated identically in all trials, determined from the maximum duration attained in the CO₂ trial. A fourth trial, breathing 5% CO₂ in O₂ for the same duration as these apneas was also performed ('Eupneic hypercapnia'). In three subjects, spleen size was measured using ultrasonic imaging.

RESULTS:

Haemoglobin increased by 4% after apneas in the 'Hypercapnia' trial (P = 0.002) and by 3% in the 'Normocapnia' trial (P = 0.011), while the 'Hypocapnia' and 'Eupneic hypercapnia' trials showed no changes. The 'easy' phase of apnea, i.e., the period without involuntary breathing movements, was longest in the 'Hypocapnia' trial and shortest in the 'Hypercapnia' trial. A decrease in spleen size was evident in the hypercapnic trial, whereas in the hypocapnia trial spleen size increased, while only minor changes occurred in the other trials. No differences were observed between trials in the cardiovascular diving response.

CONCLUSION:

There appears to be a dose-response effect of CO₂ on triggering splenic contraction during apnea in the absence of hypoxia.

Keywords
hypercapnia spleen contraction
National Category
Physiology
Identifiers
urn:nbn:se:miun:diva-15820 (URN)000301886700002 ()22437969 (PubMedID)2-s2.0-84858788803 (Scopus ID)
Available from: 2012-02-02 Created: 2012-02-02 Last updated: 2018-01-12Bibliographically approved
Schagatay, E., Richardson, M. X. & Lodin-Sundström, A. (2012). Size matters: Spleen and lung volumes predict performance in human apneic divers. Frontiers in Physiology, 3(JUN), Art. no. 173
Open this publication in new window or tab >>Size matters: Spleen and lung volumes predict performance in human apneic divers
2012 (English)In: Frontiers in Physiology, ISSN 1664-042X, Vol. 3, no JUN, p. Art. no. 173-Article in journal (Refereed) Published
Abstract [en]

Humans share with seals the ability to contract the spleen and increase circulating hemat-ocrit, 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 15s for spleen volume and 60s forVC. We conclude that both spleen- and lung volume predict apnea performance in elite divers. © 2012 Schagatay, Richardson and Lodin-Sundström.

Keywords
Breath-hold, Diving capacity, Diving response, Hematocrit, Mammalian, Spleen contraction, Training, Vital capacity
National Category
Sport and Fitness Sciences
Identifiers
urn:nbn:se:miun:diva-17259 (URN)10.3389/fphys.2012.00173 (DOI)2-s2.0-84866367851 (Scopus ID)
Note

Art. No.: Article 173

Available from: 2012-10-29 Created: 2012-10-27 Last updated: 2016-10-17Bibliographically approved
Lodin-Sundström, A., Richardson, M. & Schagatay, E. (2009). Biphasic spleen contraction during apnea in divers suggests chemoreceptor input. In: Abstract EUBS Aberdeen, UK, 25-28 Aug, 2009..
Open this publication in new window or tab >>Biphasic spleen contraction during apnea in divers suggests chemoreceptor input
2009 (English)In: Abstract EUBS Aberdeen, UK, 25-28 Aug, 2009., 2009Conference paper, Published paper (Refereed)
National Category
Microbiology
Identifiers
urn:nbn:se:miun:diva-10258 (URN)
Available from: 2009-10-29 Created: 2009-10-29 Last updated: 2011-04-07Bibliographically approved
Schagatay, E., Richardson, M., Lodin-Sundström, A. & Engan, H. (2009). Hypercapnia augments spleen contraction and Hb increase during apnea: Meeting abstract. In: Journal of Physiological Sciences Suppl 1, 2009. Paper presented at IUPS in Kyoto, Japan 27 Jul – 1 Aug 2009 (pp. 268-268). Tokyo: Springer
Open this publication in new window or tab >>Hypercapnia augments spleen contraction and Hb increase during apnea: Meeting abstract
2009 (English)In: Journal of Physiological Sciences Suppl 1, 2009, Tokyo: Springer, 2009, p. 268-268Conference paper, Published paper (Refereed)
Place, publisher, year, edition, pages
Tokyo: Springer, 2009
Series
Journal of Physiological Sciences, ISSN 1880-6546 ; 59
National Category
Microbiology
Identifiers
urn:nbn:se:miun:diva-10253 (URN)000271023101680 ()
Conference
IUPS in Kyoto, Japan 27 Jul – 1 Aug 2009
Available from: 2009-10-29 Created: 2009-10-29 Last updated: 2013-03-23Bibliographically approved
Richardson, M., de Bruijn, R. & Schagatay, E. (2009). Hypoxia augments apnea-induced increase in hematocrit and hemoglobin concentration. European Journal of Applied Physiology, 105(1), 63-68
Open this publication in new window or tab >>Hypoxia augments apnea-induced increase in hematocrit and hemoglobin concentration
2009 (English)In: European Journal of Applied Physiology, ISSN 1439-6319, E-ISSN 1439-6327, Vol. 105, no 1, p. 63-68Article in journal (Refereed) Published
Abstract [en]

Increased hemoglobin concentration (Hb) and hematocrit (Hct) attributable to spleen contraction raises blood gas storage capacity during apnea, but the mechanisms that trigger this response have not been clarified. We focused on the role of hypoxia in triggering these Hb and Hct elevations. After horizontal rest for 20 min, 10 volunteers performed 3 maximal apneas spaced by 2 min, each preceded by a deep inspiration of air. The series was repeated using the same apneic durations but after 1 min of 100% oxygen breathing and oxygen inspiration prior to apneas. Mean apneic durations were 150s, 171s, and 214s for apneas 1, 2, and 3, respectively. Relative to pre-apnea values, the mean post-apneic arterial oxygen saturation nadir was 84.7% after air and 98% after oxygen. A more pronounced elevation of both Hb and Hct occurred during the air trial: after apnea 1 with air, mean Hb had increased by 1.5% (P<0.01), but no clear increase was found after the first apnea in with oxygen. After the third apnea with air Hb had increased by 3.0% (P<0.01), and with oxygen by 2.0% (P<0.01). After the first apnea with air Hct had increased by 1.9% (P<0.01) and after 3 apneas by 3.0% (P<0.01), but Hct did not change significantly in the oxygen trial. In both trials, Hb and Hct were at pre-apneic levels 10 min after apneas. Diving bradycardia during apnea was the same in both trials. We concluded that hypoxia is essential in inducing spleen-related Hb and Hct increase during apnea.

Keywords
Breath-hold, apnea, hematocrit, spleen contraction, diving response, diving reflex
National Category
Biological Sciences Microbiology
Identifiers
urn:nbn:se:miun:diva-4364 (URN)10.1007/s00421-008-0873-9 (DOI)000262411500010 ()18839204 (PubMedID)2-s2.0-58549090876 (Scopus ID)5598 (Local ID)5598 (Archive number)5598 (OAI)
Available from: 2008-11-29 Created: 2008-11-29 Last updated: 2017-12-12Bibliographically approved
Schagatay, E., Engan, H., Lodin-Sundström, A. & Richardson, M. (2009). Increase in reticulocyte count after 2 weeks of apne training: Meeting abstract. In: Journal of Physiological Sciences, Suppl 1, 2009. Paper presented at IUPS in Kyoto, Japan 27 Jul – 1 Aug 2009 (pp. 496-496). Tokyo: Springer
Open this publication in new window or tab >>Increase in reticulocyte count after 2 weeks of apne training: Meeting abstract
2009 (English)In: Journal of Physiological Sciences, Suppl 1, 2009, Tokyo: Springer, 2009, p. 496-496Conference paper, Published paper (Refereed)
Place, publisher, year, edition, pages
Tokyo: Springer, 2009
Series
Journal of Physiological Sciences, ISSN 1880-6546 ; 59
National Category
Microbiology
Identifiers
urn:nbn:se:miun:diva-10254 (URN)000271023103417 ()
Conference
IUPS in Kyoto, Japan 27 Jul – 1 Aug 2009
Available from: 2009-10-29 Created: 2009-10-29 Last updated: 2013-03-23Bibliographically approved
Lodin-Sundström, A., Engan, H., Richarson, M. & Schagatay, E. (2009). Oxygen conservation by the diving response improved after 2 weeks of apnea training. In: 14th Annual Congress of the ECSS in Oslo, Norway 24-27 June 2009.
Open this publication in new window or tab >>Oxygen conservation by the diving response improved after 2 weeks of apnea training
2009 (English)In: 14th Annual Congress of the ECSS in Oslo, Norway 24-27 June 2009, 2009Conference paper, Published paper (Refereed)
National Category
Microbiology
Identifiers
urn:nbn:se:miun:diva-10249 (URN)
Available from: 2009-10-29 Created: 2009-10-29 Last updated: 2009-10-29Bibliographically approved
de Bruijn, R., Richardson, M. & Schagatay, E. (2009). Oxygen-conserving effect of the diving response in the immersed human. Diving and hyperbaric medicine, 39(4), 193-199
Open this publication in new window or tab >>Oxygen-conserving effect of the diving response in the immersed human
2009 (English)In: Diving and hyperbaric medicine, ISSN 1833-3516, Vol. 39, no 4, p. 193-199Article in journal (Refereed) Published
Abstract [en]

Research involving the human diving response has often simulated diving by apneic face immersion. However, no comparisons of cardiovascular responses and their oxygen- conserving function have been made between simulated diving and apneic face immersion when the body is constantly immersed as during diving. We compared the diving response and its effects on arterial oxygen saturation during apneas in horizontal dry body and immersed body positions. Both air and water temperatures were 23ºC. Twelve near-maximal apneas of the same duration were completed by 17 subjects. Four series of 3 apneas each were conducted: dry body apnea (DA), dry body, face-immersion apnea (DFIA), immersed body apnea (IA), and immersed body, face-immersion apnea (IFIA). Heart rate, skin capillary blood flow, arterial blood pressure, arterial hemoglobin saturation, lung volume and end-tidal PACO2 and PAO2 were recorded non-invasively and responses during apneas were compared among series. Cardiovascular responses showed similar patterns in all series. Face immersion led to a greater reduction in heart rate during apnea, regardless of body immersion. Both DFIA and DA resulted in a transient skin vasoconstriction, more pronounced during DFIA (p<0.001). During body immersion skin vasoconstriction was constant, and neither IA nor IFIA reduced blood flow further. Less arterial desaturation occurred after both FIA series, suggesting an oxygen-conserving effect of the more powerful diving response associated with face immersion in both body positions. We conclude that a similar oxygen-conserving diving response is triggered by apnea and face immersion during full-body immersion in cool water, as in the dry body model.

Keywords
Apnea, bradycardia, oxygen conservation, vasoconstriction, immersion
National Category
Microbiology
Identifiers
urn:nbn:se:miun:diva-6186 (URN)000273113700004 ()2-s2.0-75149148221 (Scopus ID)1903 (Local ID)1903 (Archive number)1903 (OAI)
Available from: 2009-01-29 Created: 2009-01-29 Last updated: 2010-06-14Bibliographically approved
Lodin-Sundström, A., Richardson, M. & Schagatay, E. (2009). Spleen contraction and erythrocyte release in elite apnea divers during submaximal and maximal effort apneas. In: 14th Annual Congress of the ECSS in Oslo, Norway 24-27 June 2009.
Open this publication in new window or tab >>Spleen contraction and erythrocyte release in elite apnea divers during submaximal and maximal effort apneas
2009 (English)In: 14th Annual Congress of the ECSS in Oslo, Norway 24-27 June 2009, 2009Conference paper, Published paper (Refereed)
National Category
Microbiology
Identifiers
urn:nbn:se:miun:diva-10250 (URN)
Available from: 2009-10-29 Created: 2009-10-29 Last updated: 2011-04-07Bibliographically approved
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