The heart rate performance curve (HRPC) in maximal incremental cycle ergometer exercise demonstrated three different patterns such as downward, linear or inverse versions. The downward pattern was ...found to be the most common and therefore termed regular. These patterns were shown to differently influence exercise prescription, but no data are available for running. This study investigated the deflection of the HRPC in maximal graded treadmill tests (GXT) of the 4HAIE study.
Additional to maximal values, the first and second ventilatory thresholds as well as the degree and the direction of the HRPC deflection (k
) were determined from 1,100 individuals (489 women) GXTs. HRPC deflection was categorized as downward (k
< -0.1), linear (-0.1 ≤ k
≤ 0.1) or inverse (k
> 0.1) curves. Four (even split) age- and two (median split) performance-groups were used to investigate the effects of age and performance on the distribution of regular (= downward deflection) and non-regular (= linear or inverse course) HR curves for male and female subjects.
Men (age: 36.8 ± 11.9 years, BMI: 25.0 ± 3.3 kg m
, VO
: 46.4 ± 9.4 mL min
. kg
) and women (age: 36.2 ± 11.9 years, BMI: 23.3 ± 3.7 kg m
, VO
: 37.4 ± 7.8 mL min
. kg
) presented 556/449 (91/92%) downward deflecting, 10/8 (2/2%) linear and 45/32 (7/6%) inverse HRPC´s. Chi-squared analysis revealed a significantly higher number of non-regular HRPC´s in the low-performance group and with increasing age. Binary logistic regression revealed that the odds ratio (OR) to show a non-regular HRPC is significantly affected by maximum performance (OR = 0.840, 95% CI = 0.754-0.936,
= 0.002) and age (OR = 1.042, 95% CI = 1.020-1.064,
< 0.001) but not sex.
As in cycle ergometer exercise, three different patterns for the HRPC were identified from the maximal graded treadmill exercise with the highest frequency of regular downward deflecting curves. Older subjects and subjects with a lower performance level had a higher probability to show a non-regular linear or inverted curve which needs to be considered for exercise prescription.
The aim of this study was to investigate the associations between cardiorespiratory fitness (CRF), long-term air pollution exposure and biochemical markers of oxidative status and inflammation. This ...is a cross-sectional investigation focusing on biochemical markers of oxidative status and inflammation. Participants were Caucasian (N = 1188; age 18-65 years) who lived for at least 5 years in a high air-polluted (Moravian-Silesian; MS) or low air-polluted (South Bohemia; SB) region of the Czech Republic. Healthy runners and inactive individuals were recruited. A multiple regression analysis was used to explain the relationship between multiple independent variables (CRF, trunk fat mass, sex, socioeconomic status, and region (MS region vs. SB region) and dependent variables (oxidative status, inflammation). CRF, trunk fat mass, age and sex significantly predicted almost all selected markers of oxidative status and inflammation (except GSSG, GSH/GSSG and BDNF). Participants living in the MS region presented significantly higher GPx (by 3.1%) and lower BDNF values (by 4.5%). All other investigated biochemical markers were not significantly influenced by region. We did not find meaningful interactions between long-term air-pollution exposure versus markers of oxidative status and inflammation. However, we showed various significant interactions with sex, age, CRF and body composition. The significant association of living in the high air polluted MS region with the BDNF level warrants further attention.
This study aimed to investigate the effect of a 12-week very low-carbohydrate, high-fat (VLCHF) diet and exercise on biomarkers of inflammation in healthy individuals. Since the anti-inflammatory ...effects of a ketogenic diet have been established, we hypothesized that the VLCHF diet, along with exercise, would have an additional favorable effect on biomarkers of inflammation. Twenty-four healthy individuals were allocated to the VLCHF diet (VLCHF: N = 12, age 25.3 ± 2.0 years, body mass 66.7 ± 9.8 kg, fat mass 21.5% ± 4.9%), or habitual diet (HD: N = 12, age 23.9 ± 3.8 years, body mass 72.7 ± 15.0 kg, fat mass 23.4 ± 8.4 %) group. Biomarkers of inflammation (adiponectin, leptin, and high-sensitive interleukin-6 hs-IL-6) and substrate metabolism (glycated hemoglobin, fasting glucose, triacylglycerides, and cholesterol) were analyzed from blood at baseline and after 12 weeks. The adiponectin-leptin ratio significantly increased in the VLCHF group after the intervention period (ES 95% CL: −0.90 −0.96, −0.77, P ≤ .001, BF10 = 22.15). The adiponectin-leptin ratio changes were associated with both a significant increase in adiponectin (−0.79 −0.91, −0.54, P ≤ .001, BF10 = 9.43) and a significant decrease in leptin (0.58 0.19, 0.81, P = .014, BF10 = 2.70). There was moderate evidence of changes in total cholesterol (−1.15 −2.01, −0.27, P = .010, BF10 = 5.20), and LDL cholesterol (−1.12 −2.01, −0.21, P = .016, BF10 = 4.56) in the VLCHF group. Body weight (kg) and fat mass (%) decreased in the VLCHF group by 5.4% and 14.9%, respectively. We found that in healthy young individuals, consuming a VLCHF diet while performing regular exercise over a 12-week period produced favorable changes in body weight and fat mass along with beneficial changes in serum adiponectin and leptin concentrations. These data support the use of a VLCHF diet strategy for the primary prevention of chronic diseases associated with systemic low-grade inflammation.
The aim of this non-randomized parallel group study was to examine the 12 week effects of a very low-carbohydrate high-fat diet (VLCHF) on maximal cardiorespiratory capacity, high-intensity interval ...training (HIIT) performance, and cardiac autonomic regulation.
Twenty-four recreationally trained participants allocated to either a VLCHF (
= 12) or a habitual diet (HD;
= 12) group completed 12 weeks of a diet and exercise (VLCHF) or an exercise only intervention (HD). Maximal graded exercise tests (GXT) were performed at baseline, after 4, 8, and 12 weeks. A supervised HIIT session and the 30-15 Intermittent Fitness Test (30-15
) were conducted once a week.
Total time to exhaustion (TTE) in both GXT and 30-15
increased in both VLCHF (
= 0.005, BF
= 11.30 and
= 0.001, BF
≥ 100, respectively) and HD (
= 0.018, BF
= 3.87 and
= 0.001, BF
≥ 100, respectively) groups after 12 weeks. Absolute maximal oxygen uptake (
O
) was not changed in both groups but relative
O
increased in VLCHF in concert with reductions in body mass (66.7 ± 10.2-63.1 ± 8.5 kg). Cardiac autonomic regulation did not reveal any between-group differences after 12 weeks. VLCHF diet induced an increase in β-hydroxybutyrate, which tended to normalize during the intervention period.
The 12 week VLCHF diet did not impair high-intensity continuous or intermittent exercise lasting up to 25 min, nor did it impair maximal cardiorespiratory performance or autonomic nervous system (ANS) activity.
IntroductionAmbient air pollution is a global environmental problem, which causes adverse health effects and premature deaths worldwide. Although regular exercise and physical activity have evident ...health benefits, the influence of long-term air pollution exposure during regular outdoor running has not been definitively clarified.Methods and analysisThis study protocol describes the physiological and anthropometric perspectives of the ‘Healthy Aging in Industrial Environment’ Study – Programme 4 (4HAIE). The 4HAIE research project is intended to be a single-centre, prospective, longitudinal and multidisciplinary cohort study. The presented study protocol describes the cross-sectional measurements and analyses. Overall, 1500 adult participants (age 18–65 years), runners and inactive individuals, living in a high or low air-polluted area of the Czech Republic will be recruited. We will measure and analyse biomarkers of oxidative stress and inflammation in the blood, exercise capacity (graded exercise test and spiroergometry), blood pressure, lung function (spirometry), cardiac autonomic regulation and anthropometry (body composition).Ethics and disseminationThe 4HAIE study protocol has already been approved by the Ethics Committee of the University of Ostrava (3/2018). A detailed participant information sheet will be provided to each individual prior to obtaining their written informed consent. The study poses little to no risk to participants. The findings of this study will be disseminated at regional and international conferences, in peer-reviewed journals and via social and broadcast media.
Reinforcing the small water cycle is considered to be a holistic approach to both water resource and landscape management. In an agricultural landscape, this can be accomplished by incorporating ...agricultural conservation practices; their incorporation can reduce surface runoff, increase infiltration, and increase the water holding capacity of a soil. Some typical agricultural conservation practices include: conservation tillage, contour farming, residue incorporation, and reducing field sizes; these efforts aim to keep both water and soil in the landscape. The incorporation of such practices has been extensively studied over the last 40 years. The Soil and Water Assessment Tool (SWAT) was used to model two basins in the Czech Republic (one at the farm-scale and a second at the management-scale) to determine the effects of agriculture conservation practice adoption at each scale. We found that at the farm-scale, contour farming was the most effective practice at reinforcing the small water cycle, followed by residue incorporation. At the management-scale, we found that the widespread incorporation of agricultural conservation practices significantly reinforced the small water cycle, but the relative scale and spatial distribution of their incorporation were not reflected in the SWAT scenario analysis. Individual farmers should be incentivized to adopt agricultural conservation practices, as these practices can have great effects at the farm-scale. At the management-scale, the spatial distribution of agricultural conservation practice adoption was not significant in this study, implying that managers should incentivize any adoption of such practices and that the small water cycle would be reinforced regardless.
The interaction between rainfall erosivity parameters and splash erosion is crucial for describing the soil erosion process; however, it is rarely investigated under natural rainfall conditions. In ...this study, we conducted splash erosion experiments under natural rainfall on three sites in Central Europe. The main goal was to obtain the relationship between splash erosion of the bare soil in seedbed condition and commonly used rainfall erosivity parameters (kinetic energy, intensity, and rainfall erosivity (EI30)). All sites were equipped with a rain gauge and an optical laser disdrometer where the splash erosion was measured, with modified Morgan splash cups. In order to investigate which parameter best describes the splash erosion process for all sites, a regression analysis was performed. In total, 80 splash erosion events were evaluated. Splash erosion can be described as a linear function of total kinetic energy and a non-linear function of EI30. However, the use of the total kinetic energy led to underestimation of the splash erosion rates for highly intensive rainfalls. Therefore, better results were obtained when using average rainfall intensity as the splash erosion predictor or the kinetic energy divided by the rainfall duration. Minor differences between the replicates during splash erosion measurements indicate that the modified Morgan splash cup provides a good tool for soil erosion assessment.
Soil erosion by water is affected by the rainfall erosivity, which controls the initial detachment and mobilization of soil particles. Rainfall erosivity is expressed through the rainfall intensity ...(I) and the rainfall kinetic energy (KE). KE–I relationships are an important tool for rainfall erosivity estimation, when direct measurement of KE is not possible. However, the rainfall erosivity estimation varies depending on the chosen KE–I relationship, as the development of KE–I relationships is affected by the measurement method, geographical rainfall patterns and data handling. This study investigated how the development of KE–I relationships and rainfall erosivity estimation is affected by the use of different disdrometer types. Rainfall data were collected in 1-min intervals from six optical disdrometers at three measurement sites in Austria, one site in Czech Republic and one site in New Zealand. The disdrometers included two disdrometers of each of the following types: the PWS100 Present Weather Sensor from Campbell Scientific, the Laser Precipitation Monitor from Thies Clima and the first generation Parsivel from OTT Hydromet. The fit of KE–I relationships from the literature varied among disdrometers and sites. Drop size and velocity distributions and developed KE–I relationships were device-specific and showed similarities for disdrometers of the same type across measurement sites. This hindered direct comparison of results from different types of disdrometers, even when placed at the same site. Thus, to discern spatial differences in rainfall characteristics the same type of measurement instrument should be used.
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