Exploring the Anthropometric, Cardiorespiratory, and Haematological Determinants of Marathon Performance

AimWe aimed to investigate the main anthropometric, cardiorespiratory and haematological factors that can determine marathon race performance in marathon runners.MethodsForty-five marathon runners (36 males, age: 42 ± 10 years) were examined during the training period for a marathon race. Assessment of training characteristics, anthropometric measurements, including height, body weight (n = 45) and body fat percentage (BF%) (n = 33), echocardiographic study (n = 45), cardiopulmonary exercise testing using treadmill ergometer (n = 33) and blood test (n = 24) were performed. We evaluated the relationships of these measurements with the personal best marathon race time (MRT) within a time frame of one year before or after the evaluation of each athlete.ResultsThe training age regarding long-distance running was 9 ± 7 years. Training volume was 70 (50–175) km/week. MRT was 4:02:53 ± 00:50:20 h. The MRT was positively associated with BF% (r = 0.587, p = 0.001). Among echocardiographic parameters, MRT correlated negatively with right ventricular end-diastolic area (RVEDA) (r = −0.716, p < 0.001). RVEDA was the only independent echocardiographic predictor of MRT. With regard to respiratory parameters, MRT correlated negatively with maximum minute ventilation indexed to body surface area (VEmax/BSA) (r = −0.509, p = 0.003). Among parameters of blood test, MRT correlated negatively with haemoglobin concentration (r = −0.471, p = 0.027) and estimated haemoglobin mass (Hbmass) (r = −0.680, p = 0.002). After performing multivariate linear regression analysis with MRT as dependent variable and BF% (standardised β = 0.501, p = 0.021), RVEDA (standardised β = −0.633, p = 0.003), VEmax/BSA (standardised β = 0.266, p = 0.303) and Hbmass (standardised β = −0.308, p = 0.066) as independent variables, only BF% and RVEDA were significant independent predictors of MRT (adjusted R2 = 0.796, p < 0.001 for the model).ConclusionsThe main physiological determinants of better marathon performance appear to be low BF% and RV enlargement. Upregulation of both maximum minute ventilation during exercise and haemoglobin mass may have a weaker effect to enhance marathon performance.Clinical Trial Registrationwww.ClinicalTrials.gov, identifier NCT04738877.

Dose-response modelling of total haemoglobin mass to hypoxic dose in elite speed skaters

The aim of the present study is the modelling of the total haemoglobin mass responses in altitude environment with the dose-response model in elite endurance athletes and comparison different existing approaches in the quantification of hypoxic dose.Data from seven healthy elite endurance athletes specialised in middle distance speed skating participated in the study: six males (24±1.8 years, 182 ±0.3 cm, 84 ±1.5 kg, BMI 23.2±0.6 kg/m2, 59.3±1.5 ml/kg/min) and one female (21 years, 164 cm, 56 kg, BMI 17.1 kg/m2, 59.9 ml/kg/min). Data were collected during a 3-month training period which included two training camps (14 +14 days) at sea level and two training camps (21+21 days) at altitude of 1224 m and 1850 m above sea level. Total haemoglobin mass (tHb-mass) were measured before the start of the season (baseline) and before and after each training camp (seven measurements) using an optimized CO-rebreathing method, training loads and oxygen saturation at altitude were measured and hypoxic dose were calculated.Mean total haemoglobin mass for the male group at the base line were 1067±83 g, before the training camp 1 were 1095±82 g, after TC1 1113±105 g, before the training camp 2 (TC2) 1107±88 g, after TC2 1138±104 g. For the female athlete at the base line were 570 g, after TC1 564 g, after TC2 582 g.The increase of tHb-mass after TC2 were 3,25% and were significant (p<0,005). Mean hypoxic dose for the male group TC1 were %·h (98%) 1078±157, %·h (95%) 79±57, and km.h 473±1 and at TC2 were %·h(98%) 1586±585, %·h (95%) 422±182, and km.h 893±18 and were different from TC1 (p<0,05) for %·h (95%) and km.h methods. For the female athlete hypoxic dose at TC1 were %·h (98%) 970, %·h (95%) 32, and km.h 470 and at TC2 were %·h(98%) 1587, %·h (95%) 289, and km.h 900.The relationship between hypoxic dose and haematological response was analysed with a non-linear model. The magnitude of the increase of the total haemoglobin mass were investigated using simulation procedures based upon individual responses to the hypoxic dose. We introduced a measurement error to the list square method as a way of avoiding overfitting problem. Dose-response mathematical model between hypoxic dose and total haemoglobin mass was developed. Modelled total haemoglobin mass was within measurement error range. This model is suitable for the computer simulations. The individual response to hypoxic dose due to model data was different. Maximal values in total haemoglobin mass that can be achieved by male athletes according to the model was 1321.9 ± 32 g. The model predicted that (τ) erythrocyte life span is 73.8 ± 9.0 days. Moreover, highest value of individual tHb-mass increase after returning to the sea level according to the model was16.3 ±0.7 days.The model developed in the current study describes the time course of total haemoglobin mass during altitude exposure and post-altitude decline in elite speed skaters.

Factors Contributing to CO Uptake and Elimination in the Body: A Critical Review

Background: Carbon monoxide (CO) poisoning is an important public health issue around the world. Research indicates that many factors may be related to the rate of CO uptake and elimination in the human body. However, some factors related to CO uptake and elimination are considered controversial. Relatively little attention has been devoted to review and synthesis of factors affecting CO uptake and elimination. Purpose: This paper provides a critical scoping review of the factors and divides them into four aspects, including environmental, demographic, physiological and treatment factors. Methods: We searched the scientific databases for research that has proposed a mathematical equation as a synthesis of quantities related to CO poisoning, CO elimination, CO uptake, CO half-life, CO uptake and elimination and their relationships. After excluding the studies that did not meet the study criteria, there were 39 studies included in the review and the search was completed before 16 December 2019. Results and conclusion: This review discusses most of the factors that impact the rate of CO uptake and elimination. Several factors may be related to CO uptake and elimination, such as CO concentration, the duration of exposure to CO, age, sex, exercise, minute ventilation, alveolar ventilation, total haemoglobin mass and different treatments for CO poisoning. Although some potential factors were not included in the review, the findings are useful by presenting an overview for discussing factors affecting CO uptake and elimination and provide a starting point for further study regarding strategies for CO poisoning and the environmental standard of CO.