Individual variations and sex differences in hemodynamics with percutaneous arterial oxygen saturation (SpO2) in young Andean highlanders in Bolivia

Abstract

Background Many studies have reported specific adaptations to high altitude, but few studies have focused on physiological variations in high-altitude adaptation in Andean highlanders. This study aimed to investigate the relationships between SpO2 and related factors, including individual variations and sex differences, in Andean highlanders. Methods The participants were community-dwelling people in La Paz, Bolivia, aged 20 years and over (age range 20–34 years). A total of 50 men and 50 women participated in this study. Height, weight, SpO2, hemoglobin concentration, finger temperature, heart rate, and blood pressure were measured. Information about lifestyle was also obtained by interview. Results There were individual variations of SpO2 both in men (mean 89.9%, range 84.0–95.0%) and women (mean 91.0%, range 84.0–96.0%). On Student’s t test, men had significantly lower heart rate (p = 0.046) and SpO2 (p = 0.030) than women. On the other hand, men had significantly higher SBP (p < 0.001), hemoglobin (p < 0.001), and finger temperature (p = 0.004). In men, multiple stepwise regression analysis showed that a higher SpO2 was correlated with a lower heart rate (β = − 0.089, p = 0.007) and a higher finger temperature (β = 0.308, p = 0.030) (r2 for model = 0.18). In women, a higher SpO2 was significantly correlated with a higher finger temperature (β = 0.391, p = 0.015) (r2 for model = 0.12). A higher SpO2 was related to a higher finger temperature (β = 0.286, p = 0.014) and a lower heart rate (β = − 0.052, p = 0.029) in all participants (r2 for model = 0.21). Residual analysis showed that individual SpO2 values were randomly plotted. Conclusion Random plots of SpO2 on residual analysis indicated that these variations were random error, such as biological variation. A higher SpO2 was related to a lower heart rate and finger temperature in men, but a higher SpO2 was related to finger temperature in women. These results suggest that there are individual variations and sex differences in the hemodynamic responses of high-altitude adaptation in Andean highlanders.

Seasonality and Sex-Biased Fluctuation of Birth Weight in Tibetan Populations

“…This proposal is consistent with the previous observation that male fetuses suffer more than female fetuses in an adverse maternal environment, and a higher expression of ADAM12 was detected in mothers who carry male fetuses in the mid-trimester than those carrying female fetuses, reflecting a sex-biased placental response, resulting in a higher prevalence of preeclampsia for male-carrying mothers (Myers et al 2015). In addition, for adults, there are sex differences in highaltitude adaptation (Murphy 2014;Nishimura et al 2020), which is in line with the proposed male-biased hypoxic response. Although the molecular mechanism remains unclear, a rat study found sex hormones could impact ventilator response to hypoxia during critical periods of respiratory development, and male rats show severer and more prevalent hypoxia response than female rats (Holley et al 2012).…”

Individual variations and sex differences in hemodynamics and percutaneous arterial oxygen saturation (SpO2) in Tibetan highlanders of Tsarang in the Mustang district of Nepal

“…We have previously reported sex and individual differences in hemodynamics and SpO 2 in young Andean highlanders in Bolivia (altitude, 3700–4000 m) in a study of a similar duration, using the same protocol [ 14 ]. SpO 2 was higher in the present study (mean [95 % CI ], 92.4% [92.0–92.8%]) compared with the Andean highlanders (91% [90.0–91.0%]).…”

“…Although populational differences have been well discussed, there is limited knowledge of physiological variations in highlanders [ 3 , 10 ]. From the perspective of physiological anthropology, various studies have conducted field research to investigate variation in physiological response from the perspective of acute hypobaric hypoxia in lowlanders [ 11 , 12 ] or of physiological variation in highlanders [ 6 , 13 , 14 ]. In our previous field research, we investigated the health status of Tibetans in Tsarang village (altitude, 3570 m) [ 6 ].…”

“…We have also investigated individual variations and sex differences in the percutaneous arterial oxygen saturation (SpO 2 ) of young Andean highlanders in Bolivia (altitude, 3700–4000 m). As these studies share common measurement devices and protocols [ 6 , 14 ], the physiological states can be compared between these two populations.…”

Effect of EGLN1 Genetic Polymorphisms on Hemoglobin Concentration in Andean Highlanders

“…The study subjects had no documented clinical problems such as cardiovascular and respiratory diseases. Of note, these subjects were also recruited in our previous studies on toothache experience and physiological traits [40,41].…”