Age, sex, endurance capacity, and chronic heart failure affect central and peripheral factors of oxygen uptake measured by non-invasive and continuous technologies: support of pioneer work using invasive or non-continuous measures

Abstract

IntroductionIt is known that maximum oxygen uptake depends on age, sex, endurance capacity, and chronic heart failure. However, due to the required invasive or often applied non-continuous approaches, less is known on underlying central and peripheral factors. Thus, this study aimed to investigate the effects of age, sex, endurance capacity, and chronic heart failure on non-invasively and continuously measured central and peripheral factors of oxygen uptake.Methods15 male children (11 ± 1 years), 15 male (24 ± 3 years) and 14 female recreationally active adults (23 ± 2 years), 12 male highly trained endurance athletes (24 ± 3 years), and 10 male elders (59 ± 6 years) and 10 chronic heart failure patients (62 ± 7 years) were tested during a cardiopulmonary exercise test on a cycling ergometer until exhaustion for: blood pressure, heart rate, stroke volume, cardiac output, cardiac power output, vastus lateralis muscle oxygen saturation, and (calculated) arterio-venous oxygen difference. For the non-invasive and continuous measurement of stroke volume and muscle oxygen saturation, bioreactance analysis and near-infrared spectroscopy were used, respectively. A two-factor repeated measure ANOVA and partial eta-squared effect sizes (ηp2) were applied for statistical analyses at rest, 80, and 100% of oxygen uptake.ResultsFor the age effect, there were statistically significant group differences for all factors (p ≤ .033; ηp2≥.169). Concerning sex, there were group differences for all factors (p ≤ .010; ηp2≥.223), except diastolic blood pressure and heart rate (p ≥ .698; ηp2≤.006). For the effect of endurance capacity, there were no group differences for any of the factors (p ≥ .065; ηp2≤.129). Regarding chronic heart failure, there were group differences for the heart rate and arterio-venous oxygen difference (p ≤ .037; ηp2≥.220).DiscussionAge, sex, endurance capacity, and chronic heart failure affect central and peripheral factors of oxygen uptake measured by non-invasive and continuous technologies. Since most of our findings support pioneer work using invasive or non-continuous measures, the validity of our applied technologies is indirectly confirmed. Our outcomes allow direct comparison between different groups serving as reference data and framework for subsequent studies in sport science and medicine aiming to optimise diagnostics and interventions in athletes and patients.

Relationship among muscle strength, muscle endurance, and skeletal muscle oxygenation dynamics during ramp incremental cycle exercise

“…Given that exercise tolerance is a strong predictor of life prognosis regardless of health condition 1 – 4 , it is imperative for individuals to enhance exercise tolerance by increasing daily physical activity. The oxidative capacity in active muscles strongly influences exercise tolerance 9 – 11 , with skeletal muscle oxygenation dynamics providing partial information about this capacity 12 – 14 . Therefore, although it is crucial to focus on skeletal muscle oxygenation dynamics to improve exercise tolerance, the characteristics of individuals with high skeletal muscle oxygenation dynamics in active muscles during incremental exercise remain unclear.…”

“…Given that exercise tolerance is a strong predictor of life prognosis regardless of health condition [1][2][3][4] , it is imperative for individuals to enhance exercise tolerance by increasing daily physical activity. The oxidative capacity in active muscles strongly influences exercise tolerance [9][10][11] , with skeletal muscle oxygenation dynamics providing partial information about this capacity [12][13][14] . Therefore, although it is crucial to focus on skeletal muscle Table 3.…”

“…Therefore, when active muscles possess high oxidative capacity during the same load activity, it www.nature.com/scientificreports/ alleviates the cardiac workload. Because skeletal muscle oxygenation dynamics provides partial information about the oxidative capacity in active muscles [12][13][14] , maintaining moderate-to-high levels of both muscle strength and endurance may be beneficial for individuals with low cardiac function, such as older adults and patients with cardiac problems. Additionally, we found that leg muscle oxygenation dynamics at high-intensity loads was positively correlated with leg muscle endurance only in without low leg muscle strength and with leg muscle strength only in those without low leg muscle endurance.…”

“…During incremental exercise, VO 2 is strongly influenced by arteriovenous oxygen difference, reflecting the oxidative capacity in active muscles 9 – 11 . Muscle oxygen saturation (SmO 2 ), an indicator of skeletal muscle oxygenation, offers partial insights into the oxidative capacity in active muscles since SmO 2 reflects the balance of oxygen demand and supply in the tissue 12 – 14 . Furthermore, several previous studies have noted that individuals exhibiting a greater decrease in SmO 2 in active muscles during incremental exercise tend to demonstrate higher peak VO 2 12 , 15 – 17 .…”