Respiratory burden in obese and young asthmatics: a study of diaphragmatic kinetics

Objective: The aim of this study was to assess the diaphragm kinetics, respiratory function, and serum dosage of leptin and inflammatory cytokines (IL-6 and TNF-a) in three clinical groups: obese, asthmatic, and healthy. Methods: This is a clinical exploratory study performed on 73 youths (12-24 years of age, 42.5% male) allocated into three groups: obesity (OG, n=33), body mass index (BMIz-score) = +2, asthmatic (AG, n=26) controlled mild asthmatics, classified by GINA, and Healthy Control Group (CG, n=14). The participants were subjected to diaphragmatic ultrasound, spirometry, maximal respiratory pressure, serum leptin levels, and IL-6 and TNF-a whole blood cell culture levels. Results: Diaphragm thickness was higher in OG in comparison to AG and CG (2.0±0.4 vs 1.7±0.5 and 1.6±0.2, both with p<0.05). Maximal voluntary ventilation (MVV) was significantly lower in OG and AG in relation to the CG (82.8±21.4 and 72.5±21.2 vs 102.8±27.3, both with p<0.05). OG has the highest leptin rate among the groups (with the other two groups had p<0.05). All groups had similar TNF-a and IL-6 levels. Conclusion: The muscular hypertrophy found in the diaphragm of the obese individuals can be justified by the increase in respiratory work imposed by the chronic condition of the disease. Such increase in thickness did not occur in controlled mild asthmatics. The IL-6 and TNF-a markers detected no evidence of muscle inflammation, even though leptin was expected to be altered in obese individuals. Both obese and asthmatic patients had lower pulmonary resistance than the healthy ones.

Swimming-induced changes in pulmonary function: special observations for clinical testing

Background A special improvement in pulmonary function is found in swimmers. In clinical testing the airway reactivity is observed at certain exercise intensity and target ventilation. However, in highly trained swimmers exercising in water the reactions may not function the same way. The aim was to study the combined effects of the water environment and swimming on pulmonary function and the associations with perceived symptoms. Methods First, 412 competitive swimmers completed questionnaires concerning respiratory symptoms at different swimming intensities. Then, pulmonary function testing was performed in 14 healthy elite swimmers. Spirometry and maximal voluntary ventilation (MVV) were measured on land and in water before and after swimming. While swimming, minute ventilation (VE) tidal volume (VT) and breathing frequency (fb) were measured during competition speed swimming. Results Swimmers reported the most symptoms at competition speed intensity swimming. In the transition from the land into the water swimming body position, the ratio of forced expiratory volume in one second (FEV1) and forced expiratory capacity (FVC) (FEV1/FVC) decreased by a mean (SD) 5.3 % (3) in females and by 2.2 % (5) in males. During competition speed intensity swimming, the minute ventilation (VE) had a mean of 72 and 75 % of calculated maximal voluntary ventilation (cMVV) in females and in males, respectively. Conclusions Spirometry showed sex differences in water compared to land measurements. These differences should be considered when the effects of swimming are observed. During the intensity that triggered the symptoms the most, the VE was approximately 20 % higher than the target ventilations for clinical testing. These findings encourages specific modifications of clinical testing protocols for elite swimmers.

Breathing through a diving snorkel; theory and experiment of air flow resistance and cost of breathing

The snorkel allows a surface swimmer to observe the underwater world through the face mask without being disturbed by inhaling. The effect of a snorkel on breathing resistance and cost is widely held to be substantial. This study aims to model these parameters and to measure indirectly the actual increases. Further, resistances of differing designs and dimensions were assessed and recommendations were made concerning use and choice. Maximal voluntary ventilation in 12 seconds (MVV12) was measured in 19 volunteers seated on dry land with and without a classic J-type snorkel (inner diameter 20.5 mm). The extra and total resistances and costs were calculated using the MVV12 data and using estimated airways resistance extrapolated from subject’s demography and spirometric literature data. MVV12 measurements with snorkel showed a minute volume of 152 ± 38 L∙min-1, 6.0±3.7% lower than without snorkel (p = 7.0x10-6). The theoretical MVV12, calculated from snorkel and airways resistances, decreased by 3.2%. Experimental total breathing resistance (457 ± 83 Pa∙s∙L-1) was 6.5 ± 3.2% higher than without snorkel (p = 2.6x10-7), but the total mechanical breathing cost was unaffected by the snorkel (13.58 Watts with; 13.64 Watts without). Divers’ estimations of resistance increase were exaggerated (8.8% at rest, 23% swimming). Classical J-type snorkels with an inner diameter ≥19.5 mm add 3-16% resistance . There is no risk of hypercapnia. Scuba divers are recommended to use their snorkel to breathe more comfortably on the surface. It is recommended the snorkel be made a mandatory safety accessory. The best multipurpose snorkel (19-21 mm) has no top appendages and no water release valve.

The effect of thoracic manipulation on pulmonary function in swimmers

Objective: Spinal manipulation has been used to improve respiratory function in healthy individuals. However, it has been observed that there are no studies in the context of sports activities. The objective of this study was to analyse the effect of thoracic spinal manipulation on forced vital capacity, forced expiratory volume in one second and maximal voluntary ventilation in swimmers. Method: A randomized controlled crossover study consisting of 21 swimmers, divided into two groups (Intervention vs Control), aged 16 – 24y, where forced vital capacity, forced expiratory volume in one second and maximal voluntary ventilation were measured in five evaluation moments: at baseline and, 1 minute, 10 minutes, 20 minutes and 30 minutes following the thoracic spinal manipulation procedures. Results: ANOVA tests showed no statistically significant differences for forced vital capacity (p = 0.35) and forced expiratory volume in one second (p = 0.25) among the five evaluation moments. With the maximal voluntary ventilation there was a statistically significant (p = 0.02) reduction, observed between baseline (86.00 litres) and at 10 minutes (79.29 litres) and 30 minutes (76.24 litres). No significant differences were observed between the results of intervention and control groups. Conclusions: In the current study no significant differences were observed in pulmonary function after thoracic spinal manipulation. Future research efforts should examine the effects of different manual therapy techniques and treatment protocols.