Marcel Młyńczak

Seasonal Vitamin D Status in Polish Elite Athletes in Relation to Sun Exposure and Oral Supplementation

Vitamin D does not only influence the musculoskeletal health and mineral homeostasis but it also affects cardiovascular, endocrine, nervous, immune and mental functions, thus it is of considerable importance for both physically active people and elite athletes. However, vitamin D deficiency is common worldwide and results from inadequate endogenous skin synthesis (insufficient ultraviolet B exposure) and diet. To improve the vitamin D status elite athletes often travel to lower latitude during winter. The aim of the study was to evaluate the seasonal vitamin D status in Polish elite athletes according to the sun exposure and oral supplementation. Serum concentration of 25-hydroxyvitamin D (25(OH)D) was measured in the years 2010–2014 in 409 elite athletes, who were divided into the following groups: OUTD—outdoor sports, represented by track and field athletes, who trained in Poland; IND—weightlifters, handball and volleyball players who trained indoors in Poland; SUN—track and field athletes who trained during Polish winter in lower latitude with high sunshine exposure; SUPL—track and field athletes who trained in Poland, had an inadequate vitamin D status (25(OH)D < 30 ng/ml) and were supplemented orally. Inadequate Vitamin D status was observed in 80% of OUTD and 84% of IND athletes in winter, whereas in summer the values amounted to 42% and 83%, respectively. The athletes exposed to sun in winter had significantly higher vitamin D concentration than OUTD group. Oral supplementation improved vitamin D concentration by 45%, whereas winter sun exposure caused its increase by 85%. Except for a few summer months an inadequate status of vitamin D was found in the majority of Polish elite athletes, with the deficiency level being similar to the one observed in non-athletic population. The most serious deficiency was observed in indoor disciplines. Adequate vitamin D status can be achieved by both increased sun exposure, especially in winter, and oral supplementation. Athletes should therefore routinely assess their vitamin D status and be educated how to approach their sunlight exposure, diet and supplementation.

Impedance pneumography: Is it possible?

The main purpose of this study was to describe the technique of impedance pneumography, the noninvasive method of quantitative, long lasting examination of respiratory system. In this paper there were presented physical foundations of the method, the measurement equipment and the different approaches to the measurement procedures. Also, various types and configurations of the electrodes were shown. The validation studies of impedance pneumography using clinically accepted reference the method were described, too. Finally, there were presented some proposals for future development of the technique.

Verification of the Respiratory Parameters Derived from Impedance Pneumography during Normal and Deep Breathing in Three Body Postures

We designed a small, battery-powered impedance pneumograph intended for holter monitoring of respiratory activity. Volume-related signal from impedance pneumo-graphy (IP) and airflow signal from reference method, pneumotachometry (PNT), were registered. First derivate of IP with PNT and IP with integral of PNT signals were compared in order to calculate slope values of linear regression. The effect of respiratory rate, depths of breathing, body posture, sex and body mass index (BMI) on slope values and coefficients of determination (R2) was determined. The measurements were conducted on a group of young volunteers without any respiratory diseases. An electrode configuration known for its good linearity between impedance and volume signals was chosen. Average R2 between IP signal and integral of PNT signal was 98.05%, and between first derivative of IP signal and PNT signal – 95.75%. It was demonstrated that the slope values were individually different and affected mostly by body posture.

Design and construction of the Artificial Patient module for testing bioimpedance measuring devices

The purpose of this study was to describe the design of the electronic module for testing bioimpedance measuring devices, for example impedance cardiographs or impedance pneumographs. Artificial Patient was conceived as an electronic equivalent of the impedance of skin-electrode interface and the impedance between electrodes - measured one. Different approaches in imitating a resistance of skin and an impedance of electrode-skin connection were presented. The module was adapted for frequently applied tetrapolar electrode configuration. Therefore the design do not enclose the elements simulating impedance between skin and receiver electrodes due to negligible effect of this impedance on the current flow through the receiver. The Artificial Patient enables testing either application generators, or receiver parts, particularly the level of noise and distortions of the signal. Use of digitally controlled potentiometer allows simulating different tissue resistances changes such as constant values, very-low-frequency and low-frequency changes corresponding to those caused by breathing or heart activity. Also it allows distorting signals in order to test algorithms of artifacts attenuation.

Ambulatory Devices Measuring Cardiorespiratory Activity with Motion.

Holter-type devices with sets of sensors, enabling long-term measurement of quantitative respiratory parameters, were designed and constructed. Pneumonitor 2 was intended for physiologic and athletic applications, and Pneumonitor 3 for sleep studies. Both allow simultaneous, comfortable, ambulatory monitoring of cardiorespiratory activity, such as ECG, impedance pneumography (IP), and motion; the second device also allows pulse oximetry and uses improved setting with combined receiving ECG and IP electrodes. Preliminary results showed that our prototypes provide signals reliable to monitor heart and breathing activity quantitatively. We tested the devices in different conditions, including walking, stair-climbing, cycle ergometer training, natural daily activity, and sleep. They can quantitatively measure respiratory flows, volumes, and minute ventilation using IP after calibration. They are also able to estimate tachogram from ECG. They allow the detection of subject activity and body position via accelerometer and gyroscope, which is helpful during IP calibration and interpretation. Pneumonitor 3 also enables measurement of blood saturation with a pulse wave (pulse

Decomposition of the Cardiac and Respiratory Components from Impedance Pneumography Signals.

Impedance pneumography (IP) measures changes of thoracic electrical impedance connected with change of the air volume in the lungs. The electrode configuration used in IP applications causes that electrical heart activity is visible in the IP signals. The aim of this paper is to assess the opportunity to decompose both respiratory and cardiac components and its quality using various methods. Ten students performed static breathing sequences, intended both for calibration and testing. Our prototype, Pneumonitor 2, and the reference pneumotachometer, were used. The accuracy of calculating tidal volume and heart rate, the calibration procedure and the time of analysis, were considered. Mean 86.5% accuracy of tidal volume calculating and only 2.7% error of heart rate estimation were obtained using moving average smoothing filters, for simple short recording of free breathing calibration procedure, in three body positions. More sophisticated adaptive filtering also provided good accuracy, however the processing time was 100-times higher, compared to simple methods. It seems impedance pneumography, without ECG, could be enough for measuring basic cardiorespiratory activity, particularly during ambulatory recordings, in which the least disturbing equipment is desirable.

Improvement of Body Posture Changes Detection During Ambulatory Respiratory Measurements Using Impedance Pneumography Signals

Impedance pneumography could be used for measuring respiratory parameters quantitatively in ambulatory conditions. It was noted that body posture affects the calibration coefficient connecting the measured impedance values and their first derivatives with volume and flow reference signals. Standard techniques for automatic detection of body posture and activity usually require additional motion sensors. However, in terms of the measurement comfort, less number of sensors is needed. Single sensor mounted on the chest provides good results, however its accuracy decreases during frequent changes of body posture. The aim of this study was to assess the possibility to detect body posture changes using the impedance signal itself, without any other devices or the active cooperation of the person being studied and prospectively improving the body posture change detection method using single motion sensor (e.g. 3D accelerometer). Fifteen healthy students (11 males) performed two body posture changes - get-ups and stand-ups. Six classification techniques were checked for prediction accuracy. It was found that artificial neural networks provided the best overall accuracy (90%).

Ability to Determine Dynamic Respiratory Parameters Evaluated during Forced Vital Capacity Maneuver Using Impedance Pneumography

Flow-volume loops are used to calculate dynamic respiratory parameters. We examined whether our newly developed impedance pneumograph is able to measure properly respiratory parameters during Forced Vital Capacity (FVC) maneuver. Impedance measurements were performed using an electrode configuration known for providing good linearity between impedance pneumography (IP) and pneumo-tachometry (PNT) signals. The tests were performed on a group of 14 young volunteers (11 male and 3 female) without symptoms of respiratory dysfunctions. The volume-related signal from impedance pneumography and airflow signal from the reference method, pneumotachometry, were recorded. The IP signal was converted into volume units using a transfer function determined during calibration, and flow-volume loops for IP and PNT were obtained. Their shapes were compared using modified Mahalanobis distance metrics. Additionally, we compared the ratio of time of peak expiratory flow (PEF) to total expiratory time (TTPEF/TE) and that of volume at PEF to maximal volume (VTPEF/VE). The differences between these parameters, obtained for pneumotachometry and impedance pneumography, were statistically insignificant.

Impact of breathing mechanics, body posture and physique on heart rate variability

The aim of this work was to assess the impact of breathing mechanics, body posture and subject’s physique on heart rate variability (HRV). 13 healthy students performed series of breathing with different rates and depths, while supine, sitting and standing. Impedance pneumography (IP) and electrocardiography signals were registered. Repeated ANOVA was used to estimate the factor effect on 4 parameters proposed. For standard deviation one (SD), ratio of SD and mean heart rate (SDM), and for maximum value of cross-correlation (COR, which describing the correspondence between IP and HRV signals in term of shapes), depth and rate of breathing and body posture had statistically significant impact. Slow, deep breathing caused increase of HRV.

Automatic cough episode detection using a vibroacoustic sensor.

Cough monitoring is an important element of the diagnostics of respiratory diseases. The European Respiratory Society recommends objective assessment of cough episodes and the search for methods of automatic analysis to make obtaining the quantitative parameters possible. The cough “events” could be classified by a microphone and a sensor that measures the vibrations of the chest. Analysis of the recorded signals consists of calculating the features vectors for selected episodes and of performing automatic classification using them. The aim of the study was to assess the accuracy of classification based on an artificial neural networks using vibroacoustic signals collected from chest. Six healthy, young men and eight healthy, young women carried out an imitated cough, hand clapping, speech and shouting. Three methods of parametrization were used to prepare the vectors of episode features - time domain, time-frequency domain and spectral modeling. We obtained the accuracy of 95% using artificial neural networks.