Physiological stress markers during breath‐hold diving and SCUBA diving

Abstract

This study investigated the sources of physiological stress in diving by comparing SCUBA dives (stressors: hydrostatic pressure, cold, and hyperoxia), apneic dives (hydrostatic pressure, cold, physical activity, hypoxia), and dry static apnea (hypoxia only). We hypothesized that despite the hypoxia induces by a long static apnea, it would be less stressful than SCUBA dive or apneic dives since the latter combined high pressure, physical activity, and cold exposure. Blood samples were collected from 12 SCUBA and 12 apnea divers before and after dives. On a different occasion, samples were collected from the apneic group before and after a maximal static dry apnea. We measured changes in levels of the stress hormones cortisol and copeptin in each situation. To identify localized effects of the stress, we measured levels of the cardiac injury markers troponin ( cTnI ) and brain natriuretic peptide ( BNP ), the muscular stress markers myoglobin and lactate), and the hypoxemia marker ischemia‐modified albumin ( IMA ). Copeptin, cortisol, and IMA levels increased for the apneic dive and the static dry apnea, whereas they decreased for the SCUBA dive. Troponin, BNP , and myoglobin levels increased for the apneic dive, but were unchanged for the SCUBA dive and the static dry apnea. We conclude that hypoxia induced by apnea is the dominant trigger for the release of stress hormones and cardiac injury markers, whereas cold or and hyperbaric exposures play a minor role. These results indicate that subjects should be screened carefully for pre‐existing cardiac diseases before undertaking significant apneic maneuvers.

Maternal Serum VEGF Predicts Abnormally Invasive Placenta Better than NT-proBNP: a Multicenter Case-Control Study

“…Various physiological situations can alter human biomarker levels. Serum NT-proBNP levels can be increased by physiological stress and cardiac strain [43][44][45]. We controlled for this confounding factors by retrieving blood pre-operatively.…”

Physiology, pathophysiology and (mal)adaptations to chronic apnoeic training: a state-of-the-art review

“…Moreover, a cross-sectional study that investigated the arterial stiffness of 115 female lifelong Ama BHDs (i.e., 38 ± 8 years practicing apnoea) with age-matched physically active adults demonstrating similar arterial stiffness, cardio-ankle vascular index and β-stiffness index (Tanaka et al 2016). Therefore, in totality, despite some findings that indicate acute cardiac disturbances (Joulia et al 2015;Marlinge et al 2019), the current evidence suggests that long-term participation in apnoea-related activities does not affect cardiac health nor vascular integrity (Fig. 2).…”

Hematologic changes after short term hypoxia in non-elite apnea divers under voluntary dry apnea conditions

“…Theunissen et al reported that after the apneic phase, an elevation in the stress level markers, plasma nitric oxide and peroxinitrites as well as a reduction in thiols occurred [6]. Different markers of stress and injury also showed elevated levels: Marlinge et al observed increased levels of copeptin and ischemia modified albumin in dry static apnea [7]. Not only elevated values of catecholamines, but also elevated levels of troponin and brain natriuretic peptide were detected [8].…”

“…For leucocytes, this question arises since leucocytes play an important role in our immune system, and also because stress has a great impact on leucocyte distribution [9]. To examine the full spectrum of red blood cell distribution, not only hemoglobin and hematocrit should be examined [3,7], but also other parameters, such as red blood cells and precursor immature reticulocytes and reticulocytes. Redistribution mechanisms and hemoconcentration take place during the apneic phase [10].…”