oximetry and altitude and body mass index

Wearable devices that include pulse oximetry (SpO2 ) sensing afford the opportunity to capture oxygen saturation measurements from large cohorts under naturalistic conditions. We report here a cross-sectional analysis of 72 million SpO2 values collected from 33,080 individual participants in the Apple Heart and Movement Study, stratified by age, sex, body mass index (BMI), home altitude, and other demographic variables. Measurements aggregated by hour of day into 24-h SpO2 profiles exhibit similar circadian patterns for all demographic groups, being approximately sinusoidal with nadir near midnight local time, zenith near noon local time, and mean 0...

Investigation of pulmonary gas exchange efficacy usually requires arterial blood gas analysis (aBGA) to determine arterial partial pressure of oxygen (mPaO2 ) and compute the Riley alveolar-to-arterial oxygen difference (A-aDO2 ); that is a demanding and invasive procedure. A noninvasive approach (AGM100), allowing the calculation of PaO2 (cPaO2 ) derived from pulse oximetry (SpO2 ), has been developed, but this has not been validated in a large cohort of chronic obstructive pulmonary disease (COPD) patients...

Forrer, Aglaia, Philipp M. Scheiwiller, Maamed Mademilov, Mona Lichtblau, Ulan Sheraliev, Nuriddin H. Marazhapov, Stéphanie Saxer, Patrick Bader, Paula Appenzeller, Shoira Aydaralieva, Aybermet Muratbekova, Talant M. Sooronbaev, Silvia Ulrich, Konrad E. Bloch, and Michael Furian. Exercise performance in central Asian highlanders: A cross-sectional study. High Alt Med Biol. 00:000-000, 2021. Introduction: Life-long exposure to hypobaric hypoxia induces physiologic adaptations in highlanders that may modify exercise performance; however, reference data for altitude populations are scant...

The aim of the study was to investigate the pulmonary haemodynamic response to exercise in Central Asian high- and lowlanders. This was a cross-sectional study in Central Asian highlanders (living >2500 m) compared with lowlanders (living <800 m), assessing cardiac function, including tricuspid regurgitation pressure gradient (TRPG), cardiac index and tricuspid annular plane systolic excursion (TAPSE) by echocardiography combined with heart rate and oxygen saturation measured by pulse oximetry ( S pO2 ) during submaximal stepwise cycle exercise (10 W increase per 3 min) at their altitude of residence (at 760 m or 3250 m, respectively)...

High-altitude pulmonary hypertension (HAPH) is an altitude-related illness associated with hypoxaemia that may promote sympathetic excitation and prolongation of the QT interval. The present case-control study tests whether QT intervals, markers of malignant cardiac arrhythmias, are prolonged in highlanders with HAPH (HAPH+) compared to healthy highlanders (HH) and healthy lowlanders (LL). The mean pulmonary artery pressure (mPAP) was measured by echocardiography in 18 HAPH+ (mPAP, 34 mmHg) and 18 HH (mPAP, 23 mmHg) at 3,250 m, and 18 LL (mPAP, 18 mmHg) at 760 m, Kyrgyzstan (p < ...

Pham, Luu V., Christopher Meinzen, Rafael S. Arias, Noah G. Schwartz, Adi Rattner, Catherine H. Miele, Philip L. Smith, Hartmut Schneider, J. Jaime Miranda, Robert H. Gilman, Vsevolod Y. Polotsky, William Checkley, and Alan R. Schwartz. Cross-sectional comparison of sleep-disordered breathing in native Peruvian highlanders and lowlanders. High Alt Med Biol. 18:11-19, 2017. BACKGROUND: Altitude can accentuate sleep disordered breathing (SDB), which has been linked to cardiovascular and metabolic diseases...

Miele, Catherine H., Alan R. Schwartz, Robert H. Gilman, Luu Pham, Robert A. Wise, Victor G. Davila-Roman, Jonathan C. Jun, Vsevolod Y. Polotsky, J. Jaime Miranda, Fabiola Leon-Velarde, and William Checkley. Increased cardiometabolic risk and worsening hypoxemia at high altitude. High Alt Med Biol. 17:93-100, 2016.-Metabolic syndrome, insulin resistance, diabetes, and dyslipidemia are associated with an increased risk of cardiovascular disease. While excessive erythrocytosis is associated with cardiovascular complications, it is unclear how worsening hypoxemia of any degree affects cardiometabolic risk factors in high-altitude populations...

BACKGROUND: Altitude above sea level and body mass index are well-recognized determinants of oxygen saturation in adult populations; however, the contribution of these factors to oxygen saturation in children is less clear. OBJECTIVE: To explore the contribution of altitude above sea level and body mass index to oxygen saturation in children. METHODS: A multi-center, cross-sectional study conducted in nine cities in Mexico. Parents signed informed consent forms and completed a health status questionnaire...

OBJECTIVE: Prevalence of hypertension was examined in a widely dispersed (45 110 km(2)) representative group of Ladakhi in Northern India. The influence of hypoxic environment of wide-ranged altitude (2600-4900 m) and lifestyle change on hypertension was studied. METHODS: 2800 participants (age 20-94 years) were enrolled. Systolic blood pressure ≥140 mm Hg and/or diastolic blood pressure of ≥90 mm Hg and/or taking current anti-hypertensive medicine was defined as hypertension...

OBJECTIVE: To examine the effect of ascent rate on the induction of acute mountain sickness (AMS) in young adults during a climb to Jiaming Lake (3350 m) in Taiwan. DESIGN: Prospective, nonrandomized. SETTING: Climb from 2370 to 3350 m. PARTICIPANTS: Young adults (aged 18 to 26 years) (N = 91) chose to participate in either the fast ascent (3 days; n = 43) or slow ascent (4 days; n = 48) group (1 and 2). ASSESSMENT OF RISK FACTORS: Two criteria were used to define AMS...

Acute mountain sickness (AMS) is a common problem while ascending at high altitude. AMS may progress rapidly to fatal results if the acclimatization process fails or symptoms are neglected and the ascent continues. Extensively reduced arterial oxygen saturation at rest (R-Spo₂) has been proposed as an indicator of inadequate acclimatization and impending AMS. We hypothesized that climbers less likely to develop AMS on further ascent would have higher Spo₂ immediately after exercise (Ex-Spo₂) at high altitudes than their counterparts and that these postexercise measurements would provide additional value for resting measurements to plan safe ascent...

AIM: We did a population-based cross-sectional study to investigate the prevalence and risk factors of gastroesophageal reflux disease (GERD) in a high altitude area. METHODS: An observational study using a validated questionnaire consisting of demographic, lifestyle and dietary characteristics was administered in an interview based format by two clinicians on a sample of adult population residing in urban area and rural high altitude areas of Ladakh. Presence of GERD was defined as a score of ≥4 using a previously validated symptom score based on the severity and frequency of heartburn and regurgitation...

OBJECTIVE: The present study was designed to determine if low pulse oxygen saturation (SpO(2)) in post-menopausal women at high altitude was related to high serum testosterone/estradiol (T/E(2)) ratio. METHOD: Studies were carried out in 191 women living in Cerro de Pasco, Peru (4340 m above sea level) and in 56 women living in Lima (150 m asl). Body weight, height, SpO(2), hematocrit, serum follicle stimulating hormone (FSH), T and E(2) levels were measured in all women...

A range of variation in percent of oxygen saturation of arterial hemoglobin (SaO2) among healthy individuals at a given high altitude indicates differences in physiological hypoxemia despite uniform ambient hypoxic stress. In populations native to the Tibetan plateau, a significant portion of the variance is attributable to additive genetic factors, and there is a major gene influencing SaO2. To determine whether there is genetic variance in other high-altitude populations, we designed a study to test the hypothesis that additive genetic factors contribute to phenotypic variation in SaO2 among Aymara natives of the Andean plateau, a population geographically distant from the Tibetan plateau and with a long, separate history of high-altitude residence...