The algorithm used for the calculation of gas exchange affects the estimation of O2 uptake kinetics at the onset of moderate-intensity exercise.

At the start of a moderate-intensity square-wave exercise, after a short delay, breath-by-breath O2 uptake at the mouth is approximated to a mono-exponential function, whose time constant is considered matched to that of the O2 uptake of the working muscles. We compared the kinetic parameters obtained from the breath-by-breath gas exchange data yielded by the 'Independent-breath' algorithm (IND), which accounts for the changes in lung gas stores, with those obtained with the classical 'Expiration-only' algorithm (EXP). The two algorithms were applied on the same flow and gas fraction traces acquired on 10 healthy volunteers, performing 10 times the same moderate-intensity exercise transition. Repeated O2 uptake responses were stacked together and the kinetic parameters of a mono-exponential function were estimated by non-linear regression, removing the data pertaining to 1-s progressively longer initial periods (ΔTr ). Independently of ΔTr , the mean response time (time constant + time delay) obtained for the IND data was faster compared to the EXP data (∼43 s vs. ∼47 s, P < 0.001), essentially because of shorter time delays. Between ΔTr  = 16 s and ΔTr  = 29s, the time constants of the IND data decreased (30.7 s vs. 28.0 s, P < 0.05; drop = 10%), but less than those of the EXP data (32.2 s vs. 26.2 s, P < 0.001; drop = 23%); with the same ΔTr , the time constants of the two algorithms' data were not different (P > 0.07). The different decrease in the time constant, together with the different mean response time, suggests that the data yielded by the two algorithms provide a different picture of the phenomena occurring at the beginning of the exercise.

Biomonitoring of urinary metals in athletes according to particulate matter air pollution before and after exercise.

Exposure to air pollution during physical exercise is a health issue because fine particulate matter (dimension < 10 µm; PM10) includes several inhalable toxic metals. Body metal changes in athletes according to air pollution are poorly known. Urinary concentrations of 15 metals: beryllium (Be9), aluminum (Al27), vanadium (V51), chromium (Cr51 + Cr52), manganese (Mn55), cobalt (Co59), nickel (Ni61), copper (Cu63), zinc (Zn61), arsenic (As75), selenium (Se82), cadmium (Cd111 + Cd112), thallium (Tl125), lead (Pb207), and uranium (U238) were measured before and after ten 2-h training sessions in 8 non-professional Italian American-football players (18-28 years old, body mass index 24.2-33.6 kg/m2). Collectively, post-training sessions, urinary concentrations of As, Cd, Co, Cu, Mn, Ni, Pb, Se, Tl, and Zn were higher than pre-training sessions; Al, Be, Cr, and U did not change; conversely, V decreased. Subdividing training sessions according to air PM10 levels: low (< 20 µg/m3), medium (20-40 µg/m3), and high (> 40 µg/m3), pre-session and post-session urinary concentrations of Be, Cd, Cu, and Tl were significantly higher (p < 0.05) in more polluted days, whereas V concentrations were lower (p < 0.001). All the remaining metals were unaffected. We first showed that PM10 levels modulate urinary excretion of some toxic metals suggesting an effect of air pollution. The effects of toxic metals inhaled by athletes exercising in polluted air need further studies.

Influence of the fitting window on the O2 uptake kinetics at the onset of moderate intensity exercise.

The O2 uptake (V̇o2) data at the onset of an exercise are usually fitted with a mono-exponential function, after removal of the data pertaining to a conventional initial time period (ΔTr) lasting ∼20 s. We performed a thorough quantitative analysis on the effects of removing data pertaining to different ΔTr, aiming at identifying an objective method to establish the appropriate ΔTr. Breath-by-breath O2 uptake responses, acquired from 25 healthy adults performing a step moderate-intensity exercise, and 104 simulated biexponential responses, were analyzed. For all the responses, the kinetic parameters of a mono-exponential function and the corresponding asymptotic standard errors (ASEs) were estimated by nonlinear regression, removing the data pertaining to progressively longer initial periods (1 s each) up to 60 s. Four methods to establish objectively ΔTr were compared. The minimum estimated τ was obtained for ΔTr ≅ 35 s in both the V̇o2 and simulated data, that was about 30% lower compared with that obtained for ΔTr ≅ 0s. The average ASE values remained quite constant up to ΔTr ≅ 35 s, thereafter they increased remarkably. The τ used to generate the simulated response fell within the confidence intervals of the estimated τ in ∼85% of cases for ΔTr = 20 s ("20 s-w" method); this percentage increased to ∼92% of cases when ΔTr was established according to both the minimum τ and its narrowest confidence interval ("Mixed" method). In conclusion, the effects of removing V̇o2 data pertaining to different ΔTr are remarkable. The "Mixed" method provided estimated parameters close to those used to generate the simulated responses and is thus endorsed.NEW & NOTEWORTHY We propose a method to objectively establish the initial time period to be removed from the fitting window when, using a mono-exponential model, the kinetics of the fundamental component is determined on breath-by-breath O2 uptake data collected at the onset of a moderate-intensity exercise. Innovative statistical parameters ("Coverage" and "Concordance5%," applicable on simulated responses) were used to compare its performance with that of other three methods. The proposed method yielded the best "Coverage" and "Concordance5%."

Oxidative Stress Is Increased in Combined Oral Contraceptives Users and Is Positively Associated with High-Sensitivity C-Reactive Protein.

Information concerning the mechanisms underlying oxidative stress and low-grade inflammation in young healthy women predisposing eventually to future diseases is scarce. We investigated the relationship of oxidative stress and high-sensitivity C-reactive protein (hsCRP) in fertile-age women by oral combined contraceptive (OC) use. Caucasian Italian healthy non-obese women (n = 290; 100 OC-users; 190 non-OC-users; mean age 23.2 ± 4.7 years) were analyzed. Blood hydroperoxides, as oxidative stress biomarkers, were assessed by Free Oxygen Radical Test (FORT). Serum hsCRP was determined by an ultra-sensitive method (hsCRP). Markedly elevated oxidative stress (≥400 FORT Units) was found in 77.0% of OC-users and 1.6% of non-OC-users, odds ratio (OR) = 209, 95% CI = 60.9-715.4, p < 0.001. Elevated hsCRP levels ≥ 2.0 mg/L, considered risky for cardiovascular diseases (CVDs), were found in 41.0% of OC-users and 9.5% of non-OC-users, OR = 6.6, 95%CI 3.5-12.4, p < 0.001. Hydroperoxides were strongly positively correlated to hsCRP in all women (rs = 0.622, p < 0.001), in OC-users (rs = 0.442, p < 0.001), and in non-OC-users (rs = 0.426, p < 0.001). Women with hydroperoxides ≥ 400 FORT Units were eight times as likely to have hsCRP ≥ 2 mg/L. In non-OC-users only, hydroperoxides values were positively correlated with weight and body mass index, but negatively correlated with red meat, fish and chocolate consumption. Our research is the first finding a strong positive correlation of serum hydroperoxides with hsCRP, a marker of low-grade chronic inflammation, in young healthy women. Further research is needed to elucidate the potential role of these two biomarkers in OC-use associated side-effects, like thromboembolism and other CVDs.

Personalized Approach for the Management of Exercise-Related Glycemic Imbalances in Type 1 Diabetes: Comparison with Reference Method.

BACKGROUND: One of the most frequently adopted strategies to counterbalance the risk of exercise-induced hypoglycemia in patients with type 1 diabetes is carbohydrates supplement. Nevertheless, the estimation of its amount is still challenging. We investigated the efficacy of the personalized Exercise Carbohydrate Requirement Estimation System (ECRES) method compared to a tabular approach to estimate the glucose supplement needed for the prevention of exercise-related glycemic imbalances. METHOD: Twenty-six patients performed two one-hour constant intensity exercises one week apart; the amount of extra carbohydrates was estimated, in random order, by the personalized ECRES method or through the tabular approach; glycemia was determined every 30 minutes. Continuous glucose monitoring (CGM) metrics were calculated over the 48 hours preceding, and the afternoon and night following the trials. RESULTS: Applying the personalized ECRES method, a significantly lower amount of carbohydrates was administered to the active patients compared to the tabular approach, median (interquartile range): 9.0 (0.5-21.0) g vs 23.0 (21.0-25.0) g; P < .01; the two methods were similar for the sedentary patients, 18 (13.5-36.0) g vs 23.0 (21.0-27.0) g; P = NS. After overlapping CGM metrics before the exercises, both methods avoided hypoglycemia and resulted in similar glucose levels throughout them. The ECRES method led to CGM metrics within the guidelines for either the afternoon and the night just following the trials, whereas the tabular approach resulted in a significantly greater time below range in the afternoon (11.8% ± 18.2%; P < .05) and time above range during the night (39.3% ± 29.8%; P < .05). CONCLUSIONS: The results support the validity of the personalized ECRES method: although the estimated amounts of carbohydrates were lower, patients' glycemia was maintained within safe clinical limits.

Interchangeability between two breath-by-breath O2 uptake calculation algorithms in asthmatic and healthy volunteers.

INTRODUCTION: The interchangeability analysis has been recently proposed to objectively assess whether a newly developed measurement tool can substitute the older ones; this analysis assumes that the measures yielded by the compared tools should differ less than a maximum acceptable value. We aimed to assess the interchangeability rate (IR) of the breath-by-breath O2 uptake data calculated with the "Independent breath" (IND) and the "Expiration-only" (EXP) algorithms. METHODS: Oxygen, carbon dioxide fractions, and ventilatory flow were recorded continuously over 26 min in 18 asthmatic and 20 well-matched healthy volunteers at rest, during cycling, and recovery; oxygen uptake (V'O2) was calculated with the two algorithms under comparison. Coefficients of variation (CVs) of all the steady-state condition were modeled as a function of the average V'O2 values and IR was calculated accordingly. RESULTS: CVs were significantly greater in the asthmatic volunteers (F = 5.97, p < 0.05), being lower for IND compared to EXP (F > 7.04, p < 0.02). CVs decreased as a function of the reciprocal of the square root of the average V'O2. The IR, calculated on the basis of this relationship, was not significantly different in the two groups of volunteers (F = 0.77, p = 0.385); taking as reference method the IND, or EXP algorithms, the IR values were significantly different (F = 58.6, p < 0.001), amounting to 97.4 ± 2.2% or to 98.2 ± 1.7%, respectively. CONCLUSION: The relative noise of V'O2 was greater in the asthmatic volunteers compared to the healthy ones and was lower for IND compared to EXP. The interchangeability analysis suggested that IND might be a better substitute for EXP than the opposite.

Carbohydrate Requirement for Exercise in Type 1 Diabetes: Effects of Insulin Concentration.

Physical activity is a keystone of a healthy lifestyle as well as of management of patients with type 1 diabetes. The risk of exercise-induced hypoglycemia, however, is a great challenge for these patients. The glycemic response to exercise depends upon several factors concerning the patient him/herself (eg, therapy, glycemic control, training level) and the characteristics of the exercise performed. Only in-depth knowledge of these factors will allow to develop individualized strategies minimizing the risk of hypoglycemia. The main factors affecting the exercise-induced hypoglycemia in patients with T1D have been analyzed, including the effects of insulin concentration. A model is discussed, which has the potential to become the basis for providing patients with individualized suggestions to keep constant glucose levels on each exercise occasion.

Breath-by-breath oxygen uptake during running: Effects of different calculation algorithms.

NEW FINDINGS: What is the central question of this study? Breath-by-breath gas exchange analysis during treadmill exercise can be disturbed by different breathing patterns depending on cadence, and the flow sensor might be subjected to variable mechanical stress. It is still unclear whether the outcomes of the gas exchange algorithms can be affected by running at different speeds. What is the main finding and its importance? Practically, the three investigated breath-by-breath algorithms ('Wessel', 'expiration-only' and 'independent breath') provided similar average gas exchange values for steady-state conditions. The 'independent breath' algorithm showed the lowest breath-by-breath fluctuations in the gas exchange data compared with the other investigated algorithms, both at steady state and during incremental exercise. ABSTRACT: Recently, a new breath-by-breath gas exchange calculation algorithm (called 'independent breath') was proposed. In the present work, we aimed to compare the breath-by-breath O2 uptake ( V̇O2 ) values assessed in healthy subjects undergoing a running protocol, as calculated applying the 'independent breath' algorithm or two other commonly used algorithms. The traces of respiratory flow, O2 and CO2 fractions, used by the calculation algorithms, were acquired at the mouth on 17 volunteers at rest, during running on a treadmill at 6.5 and 9.5 km h-1 , and thereafter up to volitional fatigue. Within-subject averages and standard deviations of breath-by-breath V̇O2 were calculated for steady-state conditions; the V̇O2 data of the incremental phase were analysed by means of linear regression, and their root mean square was assumed to be an index of the breath-by-breath fluctuations. The average values obtained with the different algorithms were significantly different (P < 0.001); nevertheless, from a practical point of view the difference could be considered 'small' in all the investigated conditions (effect size <0.3). The standard deviations were significantly lower for the 'independent breath' algorithm (post hoc contrasts, P < 0.001), and the slopes of the relationships with the corresponding data yielded by the other algorithms were <0.70. The root mean squares of the linear regressions calculated for the incremental phase were also significantly lower for the 'independent breath' algorithm, and the slopes of the regression lines with the corresponding values obtained with the other algorithms were <0.84. In conclusion, the 'independent breath' algorithm yielded the least breath-by-breath O2 uptake fluctuation, both during steady-state exercise and during incremental running.

Comparison of different breath-by-breath gas exchange algorithms using a gas exchange simulation system.

BACKGROUND: Mechanical Gas Exchange Simulation Systems (GESS) have never been used to compare different breath-by-breath oxygen uptake calculation algorithms. METHODS: Oxygen uptakes were calculated for each GESS cycle by the "Expiration-only" algorithm (estimating inspiratory volume from the expiratory one), and by two "alveolar" algorithms (both processing inspiratory and expiratory flows and designed to account for the changes in lung gas stores). The volume of oxygen stored in the GESS from one cycle to the subsequent one was either maintained constant or increased/decreased by changing the pumped gas volumes. RESULTS: Overlapping oxygen uptakes were obtained maintaining constant the volume of oxygen stored (grand average: 0.420 ± 0.019 L/min, p = ns). The "Expiration-only" algorithm overestimated the decreases of the stored oxygen by 34%, whereas the "alveolar" algorithms underestimated the increases by 25%; in the other conditions, the changes of the stored oxygen were appropriately accounted for. CONCLUSIONS: The use of "alveolar" algorithms is recommended, particularly so when abrupt changes in the stored oxygen volume occur.

The "independent breath" algorithm: assessment of oxygen uptake during exercise.

PURPOSE: Reduction of noise of breath-by-breath gas-exchange data is crucial to improve measurements. A recently described algorithm ("independent breath"), that neglects the contiguity in time of breaths, was tested. METHODS: Oxygen, carbon dioxide fractions, and ventilatory flow were recorded continuously over 26 min in 20 healthy volunteers at rest, during unloaded and moderate intensity cycling and subsequent recovery; oxygen uptake ([Formula: see text]) was calculated with the "independent breath" algorithm (IND) and, for comparison, with three other "classical" algorithms. Average [Formula: see text] and standard deviations were calculated for steady-state conditions; non-linear regression was run throughout the [Formula: see text] data of the transient phases (ON and OFF), using a mono-exponential function. RESULTS: Comparisons of the different algorithms showed that they yielded similar average [Formula: see text] at steady state (p = NS). The standard deviations were significantly lower for IND (post hoc contrasts, p < 0.001), with the slope of the relationship with the corresponding data obtained from "classical" algorithms being < 0.69. For both transients, the overall kinetics (evaluated as time delay + time constant) was significantly faster for IND (post hoc contrasts, p < 0.001). For the ON transient, the asymptotic standard errors of the kinetic parameters were significantly lower for IND, with the slope of the regression line with the corresponding values obtained from the "classical" algorithms being < 0.60. CONCLUSION: The "independent breath" algorithm provided consistent average O2 uptake values while reducing the overall noise of about 30%, which might result in the halving of the required number of repeated trials needed to assess the kinetic parameters of the ON transient.

Calculation algorithms for breath-by-breath alveolar gas exchange: the unknowns!

PURPOSE: Several papers (algorithm papers) describe computational algorithms that assess alveolar breath-by-breath gas exchange by accounting for changes in lung gas stores. It is unclear, however, if the effects of the latter are actually considered in literature. We evaluated dissemination of algorithm papers and the relevant provided information. METHODS: The list of documents investigating exercise transients (in 1998-2017) was extracted from Scopus database. Documents citing the algorithm papers in the same period were analyzed in full text to check consistency of the relevant information provided. RESULTS: Less than 8% (121/1522) of documents dealing with exercise transients cited at least one algorithm paper; the paper of Beaver et al. (J Appl Physiol 51:1662-1675, 1981) was cited most often, with others being cited tenfold less. Among the documents citing the algorithm paper of Beaver et al. (J Appl Physiol 51:1662-1675, 1981) (N = 251), only 176 cited it for the application of their algorithm/s; in turn, 61% (107/176) of them stated the alveolar breath-by-breath gas exchange measurement, but only 1% (1/107) of the latter also reported the assessment of volunteers' functional residual capacity, a crucial parameter for the application of the algorithm. Information related to gas exchange was provided consistently in the methods and in the results in 1 of the 107 documents. CONCLUSION: Dissemination of algorithm papers in literature investigating exercise transients is by far narrower than expected. The information provided about the actual application of gas exchange algorithms is often inadequate and/or ambiguous. Some guidelines are provided that can help to improve the quality of future publications in the field.

Fluid Intake Habits in Type 1 Diabetes Individuals during Typical Training Bouts.

BACKGROUND/AIMS: Hyperglycemia may influence the hydration status in diabetic individuals. During exercise, type 1 diabetes mellitus (T1DM) individuals may be challenged by a higher risk of dehydration due to a combination of fluid losses from sweat and increased urine output via glycosuria. So far, no study has characterised spontaneous fluid intake in T1DM individuals during active trainings. METHODS: A validated questionnaire was used to assess T1DM participants' diabetes therapy, sports characteristics and fluid intake during training; results were then compared to an age- and sport-matched sample of non-diabetic individuals. RESULTS: Ninety individuals completed the survey (n = 45 T1DM individuals, n = 45 matched controls). A proportion of T1DM -individuals reported blood glucose levels greater than 10.0 mmol at both the start (28.9%) and end (24.4%) of the exercise. The mean self-reported fluid intake was greater in T1DM (0.60 ± 0.47 L·h-1) compared to that of the control (0.37 ± 0.28 L·h-1, p < 0.05). In spite of drinking fluid volumes in line with international guidelines, 84.4% of those with T1DM reported that they were still feeling thirsty at the end of their training session. CONCLUSIONS: T1DM individuals self-report spontaneously consuming fluid adequate volumes suggested by sport nutrition guidelines for non-diabetic athletes. Discrepancies in the T1DM subjectively reported feelings of thirst suggest that more education on hydration during exercise is needed for this population to adequately compensate for elevated blood glucose levels. It remains to be established whether fluid volumes suggested for healthy athletes are adequate for maintaining euhydration in T1DM patients due to their altered diuresis.

Assessing breath-by-breath alveolar gas exchange: is the contiguity in time of breaths mandatory?

PURPOSE: A new algorithm is illustrated for the determination of breath-by-breath alveolar gas exchange that neglects the contiguity in time of breaths, i.e. it allows the breaths to be partially superimposed or disjoined in time. METHODS: Traces of oxygen, carbon dioxide fractions, and ventilatory flow were recorded continuously over 20 min in 15 healthy subjects in resting conditions; at 5-min intervals, subjects voluntarily hyperventilated for ~ 30 s to induce abrupt changes in lung gas stores. Gas exchange data were calculated applying the new algorithm and were compared to those yielded by a reference algorithm, also providing values at the alveolar level. RESULTS: Average O2 uptakes (V'O2) obtained with the two algorithms were similar during quiet breathing (0.28 ± 0.06 vs. 0.29 ± 0.06 L/min; two-sided paired t test, n = 45, p = NS); during hyperventilation, average V'O2 was significantly lower applying the new algorithm compared to the reference algorithm (0.57 ± 0.15 vs. 0.65 ± 0.17 L/min; difference - 0.077 ± 0.048 L/min; two-sided paired t test, n = 45, p < 0.001). The first breath of each hyperventilation manoeuvre showed the greatest difference in V'O2 (- 0.25 ± 0.23 L/min, z test against zero, n = 45, p < 0.001). The volumes of O2 considered twice (or neglected) because of the lack of contiguity of breaths were overall small (maximum of 3 mL) and, if accounted for, had only a slight softening effect on the fluctuations of the O2 uptake. CONCLUSION: The new algorithm, which assumes each breath as the leading subject, was able to effectively account for changes in lung gas stores without requiring any predetermined value or off-line optimisation procedure.

Calculation algorithms alter the breath-by-breath gas exchange values when abrupt changes in ventilation occur.

The automatic metabolic units calculate breath-by-breath gas exchange from the expiratory data only, applying an algorithm ('expiration-only' algorithm) that neglects the changes in the lung gas stores. These last are theoretically taken into account by a recently proposed algorithm, based on an alternative view of the respiratory cycle ('alternative respiratory cycle' algorithm). The performance of the two algorithms was investigated where changes in the lung gas stores were induced by abrupt increases in ventilation above the physiological demand. Oxygen, carbon dioxide fractions and ventilatory flow were recorded at the mouth in 15 healthy subjects during quiet breathing and during 20-s hyperventilation manoeuvres performed at 5-min intervals in resting conditions. Oxygen uptakes and carbon dioxide exhalations were calculated throughout the acquisition periods by the two algorithms. Average ventilation amounted to 6·1 ± 1·4 l min-1 during quiet breathing and increased to 41·8 ± 27·2 l min-1 during the manoeuvres (P<0·01). During quiet breathing, the two algorithms provided overlapping gas exchange data and noise. Conversely, during hyperventilation, the 'alternative respiratory cycle' algorithm provided significantly lower gas exchange data as compared to the values yielded by the 'expiration-only' algorithm. For the first breath of hyperventilation, the average values provided by the two algorithms amounted to 0·37 ± 0·34 l min-1 versus 0·96 ± 0·73 l min-1 for O2 uptake and 0·45 ± 0·36 l min-1 versus 0·80 ± 0·58 l min-1 for exhaled CO2 (P<0·001 for both). When abrupt increases in ventilation occurred, such as those arising from a deep breath, the 'alternative respiratory cycle' algorithm was able to halve the artefactual gas exchange values as compared to the 'expiration-only' approach.

Strategies used by Patients with Type 1 Diabetes to Avoid Hypoglycemia in a 24×1-Hour Marathon: Comparison with the Amounts of Carbohydrates Estimated by a Customizable Algorithm.

OBJECTIVES: The preferred countermeasure to avoid exercise-related hypoglycemia was investigated in a group of patients with type 1 diabetes participating in a stressful event, a 24×1-hour relay marathon. The carbohydrates actually consumed were compared to those estimated for each patient by applying a customizable algorithm, Exercise Carbohydrates Requirement Estimating Software (ECRES), based on patient's usual therapy and diet and on the exercise characteristics. METHODS: Glycemia was tested at the start, middle and end of the races. Usual therapies and diets and the adopted countermeasures were recorded in detail. RESULTS: We studied 19 patients who walked/ran 10.4±2.8 km with a heart rate of 167±11 beats per minute. Of the 19 patients, 7 patients reduced the administered insulin (premeal bolus or basal infusion rate). Glycemia fell by the end of the races (p=0.006; median -1.8 mmol⋅L-1; interquartile range -0.4 mmol⋅L-1 to -5.3 mmol⋅L-1), despite 9 patients being hyperglycemic at the start. Of the patients, 14 concluded the race with glycemia on target, and 4 patients were hyperglycemic. Amounts of carbohydrates actually consumed (median 30 g; interquartile range 0 g to 71 g) were not significantly different from those estimated by ECRES (median 38 g; interquartile range 24 g to 68 g), the 2 quantities being significantly related (R=0.64; p=0.003). ECRES estimated lower carbohydrate levels (-13 g) than the amounts actually consumed by the 4 patients who concluded their exercises with hyperglycemia. CONCLUSIONS: Patients preferred to consume extra carbohydrates to avoid the possible exercise-induced hypoglycemia. ECRES would provide satisfactory estimates of the carbohydrate requirements, even for a stressful condition, and almost equal to the quantities consumed following medical advice.

Combined Oral Contraceptives Increase High-Sensitivity C-Reactive Protein but Not Haptoglobin in Female Athletes.

BACKGROUND: No studies have examined the effects of oral hormonal contraception on chronic low-grade inflammation as assessed by stratified levels of high-sensitivity C-reactive protein (hsCRP) in athletes. We explored the impact of combined oral contraceptives (OCs) on serum hsCRP, haptoglobin, triglycerides and cholesterol in white female athletes. METHODS: Italian sportswomen (n = 205; mean age 24 ± 5.3 years; body mass index 21 ± 2.2 kg m-2; sport activity 8.7 ± 3.65 h week-1) were analyzed according to OC use. RESULTS: Progressive hsCRP levels were evaluated in OC users (n = 53) compared to non-OC users (n = 152). Levels of hsCRP from 3.0 to <10.0 mg L-1 (at high risk of future cardiovascular events) were found in 26.4 % (14/53) of OC users and only in 2.6 % (4/153) of non-OC users (OR = 13.3, 95 % CI 4.14-42.6, P < 0.001). Risky hsCRP levels ≥1.0 mg L-1 were found in 62.3 % of OC users versus 13.2 % non-OC users (OR = 10.9, 95 % CI 5.26-22.5, P < 0.001). Protective hsCRP levels (<0.5 mg L-1) were found in 17.0 % of OC users and in 64.5 % of non-OC users (OR = 0.11, 95 % CI 0.05-0.25, P < 0.001). OC use increased serum triglycerides (P < 0.001), total cholesterol (P = 0.027) and HDL cholesterol (P = 0.018), whereas haptoglobin was unaffected. Hours of exercise week-1 had a mild inverse association with hsCRP (P = 0.048) in non-OC users only. CONCLUSIONS: OC use markedly elevated chronic low-grade inflammation in athletes, which could predispose to a higher inflammatory response to physical stress and elevate cardiovascular risk. Physical activity without OC use seemed to favor low hsCRP. Further research is needed to extend our results and to elucidate the potential effects on athletic performance of chronically elevated hsCRP. Our findings would be useful for sport physicians interpreting blood tests in athletes.