Toward a hyperventilation detection system in freediving: a proof of concept using force sensor technology.

Background And Aim: Hyperventilation before breath-hold diving (freediving) is widely accepted as a risk factor for hypoxic syncope or blackout (BO), but there is no practical way to address it before dives. This study explores the feasibility of using a force sensor to predict end-tidal carbon dioxide ( CO) to assess hyperventilation in freedivers.

Methods And Results: Twenty-one freedivers volunteered to participate during two national competitions.

Effect of exercise intensity and apnea on splenic contraction and hemoglobin increase in well-trained cross-country skiers.

The human spleen acts as a reservoir for red blood cells, which is mobilized into the systemic circulation during various conditions such as hypoxia and physical exertion. Cross-country (XC) skiers, renowned for their exceptional aerobic capacity, are regularly exposed to high-intensity exercise and local oxygen deficits. We investigated a putative dose-dependent relationship between splenic contraction and concomitant hemoglobin concentration ([Hb]) elevation across four exercise intensities in well-trained XC skiers.

Differential splenic responses to hyperoxic breathing at high altitude in Sherpa and lowlanders.

The human spleen contracts in response to stress-induced catecholamine secretion, resulting in a temporary rise in haemoglobin concentration ([Hb]). Recent findings highlighted enhanced splenic response to exercise at high altitude in Sherpa, possibly due to a blunted splenic response to hypoxia. To explore the potential blunted splenic contraction in Sherpas at high altitude, we examined changes in spleen volume during hyperoxic breathing, comparing acclimatized Sherpa with acclimatized individuals of lowland ancestry.

First Real-Life Data on the Diving Response in Healthy Children.

Swimming and diving are popular recreational activities, representing an effective option in maintaining and improving cardiovascular fitness in healthy people. To date, only little is known about the cardiovascular adaption to submersion in children. This study was conducted to improve an understanding thereof.

Unlocking the depths: multiple factors contribute to risk for hypoxic blackout during deep freediving.

Purpose: To examine the effect of freediving depth on risk for hypoxic blackout by recording arterial oxygen saturation (SpO) and heart rate (HR) during deep and shallow dives in the sea.

Methods: Fourteen competitive freedivers conducted open-water training dives wearing a water-/pressure proof pulse oximeter continuously recording HR and SpO. Dives were divided into deep (> 35 m) and shallow (10-25 m) post-hoc and data from one deep and one shallow dive from 10 divers were compared.