M. M. F. Subhan

Effects of aerobic exercise training and yoga on the baroreflex in healthy elderly persons.

It is unclear whether the age‐associated reduction in baroreflex sensitivity is modifiable by exercise training. The effects of aerobic exercise training and yoga, a non‐aerobic control intervention, on the baroreflex of elderly persons was determined. Baroreflex sensitivity was quantified by the α‐index, at high frequency (HF; 0.15–0.35 Hz, reflecting parasympathetic activity) and mid‐frequency (MF; 0.05–0.15 Hz, reflecting sympathetic activity as well), derived from spectral and cross‐spectral analysis of spontaneous fluctuations in heart rate and blood pressure. Twenty‐six (10 women) sedentary, healthy, normotensive elderly (mean 68 years, range 62–81 years) subjects were studied. Fourteen (4 women) of the sedentary elderly subjects completed 6 weeks of aerobic training, while the other 12 (6 women) subjects completed 6 weeks of yoga. Heart rate decreased following yoga (69 ± 8 vs. 61 ± 7 min−1, P < 0.05) but not aerobic training (66 ± 8 vs. 63 ± 9 min−1, P = 0.29). VO2 max increased by 11% following yoga (P < 0.01) and by 24% following aerobic training (P < 0.01). No significant change in αMF (6.5 ± 3.5 vs. 6.2 ± 3.0 ms mmHg−1, P = 0.69) or αHF (8.5 ± 4.7 vs. 8.9 ± 3.5 ms mmHg−1, P = 0.65) occurred after aerobic training. Following yoga, αHF (8.0 ± 3.6 vs. 11.5 ± 5.2 ms mmHg−1, P < 0.01) but not αMF (6.5 ± 3.0 vs. 7.6 ± 2.8 ms mmHg−1, P = 0.29) increased. Short‐duration aerobic training does not modify the α‐index at αMF or αHF in healthy normotensive elderly subjects. αHF but not αMF increased following yoga, suggesting that these parameters are measuring distinct aspects of the baroreflex that are separately modifiable.

Lung function in Pakistani welding workers.

Our objective was to study the effects of welding fumes and their duration of exposure on lung function. This was a matched case-control cross-sectional study of spirometry in 50 nonsmoking manual metal arc welders who work without the benefit of welding fume control ventilation or respiratory protective devices. Welding workers, with exposures longer than 9 years, showed a significant reduction in spirometry (forced expiratory volume in one second [FEV1], FEV1/forced vital capacity [FVC%], and peak expiratory flow [PEF]) relative to controls. Lung function in nonsmoking welding workers is impaired and stratification of results shows a dose-effect of years of welding on lung function. This effect primarily shows an obstructive pattern of airways disease. Preventive measures in developing countries have to be adopted to avert long-term lung damage in welders.

The effect of Ramadan fasting on spirometry in healthy subjects

Objectives:  Lung function tests are an important investigative tool in diagnosing respiratory diseases, judging their severity and assessing prognosis. The primary aim of the present study was to assess whether Ramadan fasting affected normal lung function values.

Underweight and overweight men have greater exercise-induced dyspnoea than normal weight men

Abstract Introduction. Persons with high or low body mass index (BMI), involved in clinical or mechanistic trials involving exercise testing, might estimate dyspnoea differently from persons with a normal BMI. Aims. Our objective was to investigate the relationship between BMI and dyspnoea during exercise in normal subjects with varying BMI. Material and methods. A total of 37 subjects undertook progressive exercise testing. Subjects were divided into three groups: underweight (UW), normal weight (NW), and overweight (OW). Dyspnoea was estimated using the visual analogue scale (VAS). Spirometry, maximum voluntary ventilation (MVV), and respiratory muscle strength (RMS) were measured. Results and discussion. The intercept of the VAS/ventilation relationship was significantly higher in NW subjects compared to UW (P = 0.029) and OW subjects (P = 0.040). Relative to the OW group, FVC (P = 0.020), FEV1 (P = 0.024), MVV (P = 0.019), and RMS (P = 0.003) were significantly decreased in the UW group. The greater levels of dyspnoea in UW subjects could possibly be due to decreased RMS. Healthy persons should aim to achieve an optimum BMI range to have the lowest exercise-induced dyspnoea.

Effect of repetitive exercise testing on breathlessness in humans.

There are conflicting reports on the reproducibility of the visual analogue scale (VAS) and the modified Borg scale for the estimation of breathlessness during exercise. In an attempt to clarify the situation, two groups of healthy subjects undertook a progressive exercise test either daily (Group A) or weekly (Group B) on 10 separate occasions. Breathlessness was estimated every 1 min using the VAS. After 10 occasions, both Group A (P <0.05) and Group B ( P <0.01) showed a significant increase in the mean intercept of the breathlessness/ventilation (VAS/ V (I)) relationship. The increase was not progressive; using change point regression, reproducible values were found to occur after approximately the fifth occasion in both subject groups. As the slope of the VAS/ V (I) relationship was highly reproducible and did not change with repeat testing, it would appear that at least two mechanisms are involved in the generation of the sensation of breathlessness. A decrease in the exercise heart rate over the same time period was significantly correlated with changes in the VAS/ V (I) intercept in both groups (P <0.01 and P <0.005 respectively). The relationship is unlikely to be causal, but may be indicative of a common underlying mechanism. It is suggested that breathlessness scores are likely to decrease as a direct result of repetitive testing over, on average, the first five periods of assessment. On the basis of this study, it may be inferred that a physiological mechanism contributes to the modulation of breathlessness during repetitive exercise testing.

Intercept Shift in the Breathlessness/ Ventilation Relationship in Response to Progressive Increase in Workload

The relationship between breathlessness based on the visual analog scale (VAS) and expired pulmonary ventilation (VE) has been investigated under different experimental conditions. The `Newcastle effect’ revealed for the first time that a repetitive exercise protocol over a period of ten days increased the intercept without change in the slope of VASNE relationship1. Whether experiments were conducted daily or weekly, the time course of the intercept plateaued after around 5 to 6 weeks of exercise training2. A similar effect has been shown to occur during volitional tracking of an inspiratory resistive breathing pattern2.

Dose response effect of cement dust on respiratory muscles competence in cement mill workers.

Abstract Electromyography (EMG) of respiratory muscles is a reliable method of assessing the ventilatory muscle function, but still its use has not been fully utilized to determine the occupational and environmental hazards on respiratory muscles. Therefore, EMG of intercostal muscles was performed to determine the dose response effect of cement dust on respiratory muscles competence. Matched cross-sectional study of EMG in 50 non-smoking cement mill workers with an age range of 20 – 60 years, who worked without the benefit of cement dust control ventilation or respiratory protective devices. EMG was performed by using surface electrodes and chart recorder. Significant reduction was observed in number of peaks (p < 0.0005), maximum peak amplitude (p < 0.0005), peak-to-peak amplitude (p < 0.0005) and duration of response (p < 0.0005) in cement mill workers compared to their matched control. Cement dust impairs the intercostal muscle competence and stratification of results shows a dose-effect of years of exposure in cement mill.

International Union of Physiological Sciences Physiology Teaching Workshop, March 31–April 1, 2012, Arabian Gulf University, Kingdom of Bahrain

Since 2009, the Department of Physiology had planned an International Union of Physiological Sciences Physiology Teaching Workshop at Arabian Gulf University. The date was set for March 5-6, 2011; however, due to civil unrest, the workshop was postponed to March 31-April 1, 2012. The workshop was a success, bringing together 92 speakers and participants from 23 countries. Twenty-eight participants from economically disadvantaged countries were given travel support. The workshop included plenary lectures, breakout workshops, poster sessions, dinners, and a social trip. On April 2, 2012, an AD Instruments satellite workshop on data-acquisition systems for laboratory teaching was held, with 60 participants from 12 countries.