Deep strokes, much like effleurage, increase muscle temperature and circulation. Muscle tightness is further reduced as the strokes enable the massage therapist to get deeper into the muscles. Due to the firmer, deeper pressure used, more blood is pushed through veins in the direction of the heart, increasing venous return.
Lymphatic drainage is a technique used to increase venous return. Lymphatic drainage is a technique that is used to improve the flow of the lymphatic system. After injury or conditions such as lymphedema, an increase in swelling occurs at the injury site.
Swelling is made up from excess fluids that have built up to protect the area from further damage. Directional strokes are used within lymphatic drainage using the lumbricals of the hands. Lymphatic drainage increases blood and lymph flow to decrease swelling and increase healing. As more fluids are drained from the body, blood flow increases resulting in an increase in venous return.
Increased venous return can help in many situations. Situations when increased venous return helps include:. Increased venous return can help pre event. Increasing venous return increases the amount of blood to be transferred back to the heart to be re-oxygenated.
The re-oxygenated blood is then delivered to the muscles around the body. The more the venous return is increased, the more oxygen will be available for the muscles to use. Increasing the amount of oxygenated blood to be delivered to the muscles provides them with an increase in energy for the event that is about to take place.
Increasing venous return also increases muscle temperature. Increasing muscle temperature allows muscles to loosen to reduce tightness and increase in range of movement. Increasing range of movement is essential pre event as it reduces the chances of injury during short bursts of movement. Stress can be reduced when venous return is increased. Stress can be shown both physically and mentally.
When venous return increases and helps to reduce muscle tightness, stress within muscles is also reduced allowing them to relax.
Allowing muscles to relax also decreases pain. Decreasing pain can help reduce stress mentally as a person is able to mentally relax without the irritation of tight, tense muscles. Increased venous return can help post surgery. Surgery can leave damaging effects on a person's body. Increasing venous return encourages a more efficient circulation to help provide injury sites with an increase in oxygen and nutrients, essential for the repair of damaged tissues and cells.
Otherwise, blood would accumulate in either the systemic or pulmonary circulations. Although cardiac output and venous return are interdependent, each can be independently regulated.
The circulatory system is made up of two circulations pulmonary and systemic situated in series between the right ventricle RV and left ventricle LV as depicted in the figure. Balance is achieved, in large part, by the Frank-Starling mechanism.
For example, if systemic venous return is suddenly increased e. Increased pulmonary venous return to the left atrium leads to increased filling preload of the left ventricle, which in turn increases left ventricular stroke volume by the Frank-Starling mechanism.
The chest was modeled in two compartments: the rib cage and the abdomen. The boundary between the rib cage and abdomen was fixed along the lower costal margin, as described in detail in the previous studies Aliverti et al. Total chest wall volume V cw was calculated as the sum of rib cage and abdominal volume V rc and V ab respectively.
Flow at the mouth was measured using a hot wire anemometer, which measured gas velocity in a tube of known cross-sectional area Sensormedics Vmax, Yorba Linda, USA , connecting the subject to the exterior of the box. Both flow meters were calibrated with a 3 L syringe. Temperature and humidity inside the box were continuously controlled with a multi-sensor device SHT11, Sensirion AG, Zuerich, Switzerland based on a hygroscopic polymer as a humidity sensitive element and a semiconductor as a temperature-sensitive element.
The air conditioning system was placed at the bottom of the body box out of the line of sight between the OEP cameras and the trunk, to allow the correct measurement of V tr , and also to avoid influencing the pneumotachograph placed on the top of the box. Pilot testing in preparation for the experiments showed that this conditioning system allowed keeping temperature quite constant inside the WBP even during exercise, but not relative humidity, which led to integration drift.
In clinical practice WBP is routinely used for pulmonary function diagnostic tests that last so short that temperature and humidity changes can be neglected. Conversely, if prolonged volume measurements are needed, for example during an exercise test, increases in temperature and humidity, caused by the subject, cause substantial thermal drift Goldman et al.
In spite of our air conditioning system, which kept air temperature in the body-box almost constant, a consistent non-linear drift of volume occurred during exercise. We used discrete wavelet transformation DWT von Borries et al. The algorithm used is based on a discrete wavelet transformation using high-pass and low-pass filters scaling function applied iteratively to the signal, which is progressively down sampled.
The low-pass filter gives the new scaling coefficients while the high-pass filter gives the wavelet coefficients in two orthogonal subspaces. The scaling and wavelet coefficient correspond to the low and high frequency components of the input. The decomposition is then repeated with the analysis filter over the scaling coefficient a number of times depending on the bandwidth of the baseline drift Rioul and Vetterli, ; Samar et al.
We used a second order discrete biohortogonal function as mother wavelet, because it best fit our signal, and because it was linear in phase, symmetrical, and had good local properties. After decomposition the input signal was then reconstructed using the same family of wavelets but forcing to zero the low frequency coefficient, representing the thermal drift. This allowed removing the thermal drift without introducing distortion and protecting the shape of the original signal.
In order to choose the correct level of wavelet decomposition and to verify if the resulting volume signal was well filtered, we did a linear regression between the first phase of quiet breathing of the filtered signal and the same part of quiet breathing of the chest wall volume, acquired by OEP, which was by definition not affected by thermal drift. During spontaneous quiet breathing these two signals should be aligned and in phase Aliverti et al.
For each trial the level with the highest R 2 resulting from this procedure was then used. The subjects were studied while sitting inside the WBP during pre-exercise baseline and submaximal constant workload exercise. We used a custom-made stepper, the only possible exercise solution because of the dimensions of the WBP.
It consisted of an electric motor used as a generator, connected to two pedals via a chain-sprocket system to transfer the movement of the pedals to the axis of the motor.
O 2 and CO 2 concentrations at the mouth were measured by paramagnetic and infrared gas analyzers, integral part of the system, calibrated with gases of known composition. The flow meter was calibrated with a 3 L syringe. For each subject, data are presented as the mean of at least 10 breaths collected pre-exercise and the last part of the three exercise bouts.
In spontaneous mode, after 1 min of sitting baseline quiet breathing during rest, while sitting in the WBP , they engaged in 5 min of stepping exercise while breathing spontaneously, followed by 4 min of recovery no exercise see Figure 1. After instructions and some practice runs they then performed several different trials for each breathing mode.
Rib cage breathing mode consisted of voluntary emphasizing inspiratory rib cage breathing, which, when effectuated correctly, resulted in ribcage volume changes over a breathing cycle while keeping abdominal volume constant. Abdominal breathing mode consisted of voluntary abdominal expiration, resulting in a decrease of abdominal volume accompanied by a simultaneous increase of abdominal pressure, followed by diaphragm contraction for inspiration, while keeping the rib cage configuration invariant.
Since abdominal and rib cage breathing modes were difficult to sustain, we shortened these to 1 min, long enough for the larger initial cardiovascular and metabolic changes to occur, while short enough to allow the subjects to correctly perform the exercise. Thus, after 1 min of quiet breathing at rest, rib cage or abdominal mode exercise were executed for 1 min, followed by 1 min of recovery.
Subjects did each exercise trial a minimum of one time, recovering between trials. The WBP was opened in between trials to reestablish the initial thermodynamic conditions. The order of the three breathing modes was randomized within and between subjects. Figure 1. Description of the experimental protocol. Pre-exercise and exercise phases were analyzed in terms of volume changes and blood shifts.
The effects of different exercise breathing patterns on blood shift and volume changes were assessed by a generalized linear mixed-model repeated measurements analysis of variance since the missing values for some of the subjects participating to the study precluded the use of simple ANOVA.
When the outcome data were not normally distributed, we used the inverse Gaussian distribution, the closest available theoretical distribution to fit the sample. The breathing modes spontaneous, rib cage, and abdominal , the phase of exercise quiet breathing vs. The subjects' variability was used as random effect. Pairwise comparisons were carried out with Holm Sidak's post-hoc test. Figure 2. Traces during spontaneous pre-exercise breathing. The difference between V tr and V L gives the volume of the blood shifted between the splanchnic vasculature and the extremities bottom panel.
Figure 3. Blood shift volume and chest wall volume variation during pre-exercise breathing A and an example of spontaneous breathing mode during exercise B. V bs swings were calculated as difference between the maximum and the minim values during each breathing of quiet breathing and exercise respectively.
The exercise intensity corresponded to an average of 4. Even though the stepping effort was equivalent in the three modes, because of the shorter durations of rib cage and abdominal breathing modes compared to spontaneous mode, steady state gas exchange was not reached in rib cage and abdominal modes duration of exercise 1 min.
Ventilatory parameters for pre-exercise and exercise are shown in Table 2. P ET CO 2 during spontaneous breathing was higher compared to pre-exercise, rib cage mode and abdominal mode Table 2. Exercise significantly increased ventilation, which passed from Representative traces of spontaneous, rib cage, and abdominal breathing modes during exercise are shown in Figure 4.
From top to bottom are depicted rib cage volume V rc , abdominal volume V ab , and trunk volume V tr , all three obtained with OEP black lines. Superimposed in red on V tr is shown WBP-measured body volume V b , the difference with V tr representing blood shifting V bs , shown in the bottom panels. Figure 4. The figure shows the three different breathing modes during exercise performed by the subjects, spontaneous A , rib cage B , and abdominal mode C respectively. This resulted in blood being displaced from the extremities to the trunk, presumably to the rib cage, as illustrated by negative values of V bs Figure 4B.
Conversely, during exercise while in abdominal breathing mode, end-expiratory abdominal volume decreased while the blood shifted from the trunk to the extremities, as indicated by the positive values of V bs Figure 4C.
Figure 5 depicts the rib cage, abdominal and total chest wall end-expiratory volumes black circles and end-inspiratory volumes white circles , at baseline and during exercise for each of the breathing modes. Exercise induced an increase in chest wall tidal volume V T , defined as the difference of end-inspiratory volume and end-expiratory volume, for all breathing modes 0. In spontaneous mode, the increase in V T was reached by an increase of end-inspiratory rib cage volume V rcEI and a concomitant decrease in end-expiratory abdominal volume V abEE.
V rcEI increased on average by 0. Distribution of the systemic cardiac output at rest and during strenuous exercise Vasodilation of arterioles in the skeletal and heart muscles and skin causes a decrease in total peripheral resistance to blood flow.
This decrease is partially offset by vasoconstriction of arterioles in other organs. But the vasodilation in muscle arterioles is not compensated, and the net result is a marked decrease in total peripheral resistance to blood flow. During exercise, the cardiac output increases more than the total resistance decreases, so the mean arterial pressure usually increases by a small amount.
Pulse pressure, in contrast, markedly increases because of an increase in both stroke volume and the speed at which the stroke volume is ejected. The cardiac output increase is due to a large increase in heart rate and a small increase in stroke volume.
The heart rate increases because of a decrease in parasympathetic activity of SA node combined with increased sympathetic activity. The stroke volume increases because of increased ventricular contractility, manifested by an increased ejection fraction and mediated by sympathetic nerves to the ventricular myocardium.
End-diastolic volume increase slightly.
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