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1.
Eur J Appl Physiol ; 123(4): 857-865, 2023 Apr.
Article in English | MEDLINE | ID: mdl-36512132

ABSTRACT

PURPOSE: To showcase results of arterial blood gases' analysis in elite breath-hold divers sampled at depths where their total lung capacities are below their residual lung volume on surface. METHODS: Three male elite breath-hold divers performed body plethysmographies to determine their lung volumes. Two dives were performed, one on normal inhalation to 60 m of depth and the second on complete exhalation to 10 m of depth. Blood samples were taken on five occasions; before the first dive, at 60 and 10 m of depth and immediately after resurfacing after both dives. RESULTS: Arterial blood gases' analysis at 60 m of depth showed an increase in partial pressures of oxygen and carbon dioxide, a consequent decrease in pH and an increase in concentration of HCO3-. After resurfacing, in two divers, values mostly returned to normal; hypoxemia was observed in one diver. At 10 m of depth, all values showed similar variation, and hypoxemia was observed in the same diver but at depth. Upon resurfacing, all values returned to normal. CONCLUSION: This is the first study performed at depths where the total lung capacities of participants are below their residual lung volumes at the surface. Partial pressure of carbon dioxide increases at depth to higher than normal values causing pH to decrease thus exceeding the buffering potential of the blood. In addition, previous assumptions that maximum depth in breath-hold divers is where total lung capacity is reduced to their residual volume proved wrong as our group of divers had no symptoms after resurfacing.


Subject(s)
Carbon Dioxide , Diving , Humans , Male , Breath Holding , Oxygen , Hypoxia
2.
Immunol Lett ; 248: 45-55, 2022 08.
Article in English | MEDLINE | ID: mdl-35709930

ABSTRACT

Exercise has many beneficial effects for our body, but can become detrimental at high intensity, especially for our immune system. Little is known about the underlying mechanism of impaired immune functionality under conditions of intense physical strain. Freedivers, people who dive to high depths on a single breath, perform extreme exercise under anaerobic conditions. In this study, we investigated the impact of freediving on the cytotoxic arm of the immune system. At rest, elite freedivers did not display changes in their immunological profile compared to non-diving controls. In contrast, after a freedive, granzyme B and IL-2 production were reduced, whereas IFNγ and TNF secretion were increased by cytotoxic immune cells. Using in vitro models mimicking freedive conditions, we could show that hypoxia in combination with stress hyperglycemia had a negative impact on Granzyme B secretion, whereas IL-2 production was inhibited by stress hormones. Our findings suggest that in response to extreme exercise, cytotoxic immune cells transiently change their functional profile to limit tissue damage.


Subject(s)
Hypoxia , Interleukin-2 , Anaerobiosis , Granzymes , Humans , Lymphocytes
3.
Diving Hyperb Med ; 51(3): 299-302, 2021 Sep 30.
Article in English | MEDLINE | ID: mdl-34547782

ABSTRACT

INTRODUCTION: The aim of reporting these two cases is to present visual evidence by bronchoscopy of the origin of haemoptysis in two elite breath-hold divers. CASE REPORTS: Two male elite breath-hold divers of similar physical characteristics presented to our clinic after performing dives of up to 75 and 59 meters of seawater depth for 2:30 and 2:35 (minutes:seconds) respectively. Both patients presented with haemoptysis. Lung ultrasound was performed. The first patient had crackles on chest auscultation, overt pulmonary oedema clinically and 90 ultrasound lung comets. The second patient had no oedema or crackles, but presented with 20 ultrasound lung comets. Video bronchoscopy was performed which showed traces of blood coming from all three segments of the right upper lobe in both patients. The rest of the airways and lungs were intact. CONCLUSIONS: These finding suggest that the apical parts of the lungs are the most prone to deep-dive induced damage. The precise mechanism of lung barotrauma and haemoptysis in breath-hold divers remains to be elucidated. These findings may be of importance for a better understanding of the underlying pathology of haemoptysis.


Subject(s)
Diving , Pulmonary Edema , Breath Holding , Diving/adverse effects , Hemoptysis/etiology , Humans , Lung , Male , Pulmonary Edema/diagnostic imaging , Pulmonary Edema/etiology , Ultrasonography
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