The prediction of recommended energy expenditure for an 8 h work-day using an air-purifying respirator

Using Kinect body joint detection system to predict energy expenditures during physical activities

The purpose of this study was to explore the potential of Kinect body joint detection to facilitate the calculation of energy expenditure during exergame exercises. Two Kinect-based biomechanical models - mechanical energy (KineticE) and work (WorkE) were employed to estimate the energy expenditure during four Wii™ exergame session. Consequently, two stepwise regression models were developed from nineteen participants' data and then validated by five holdout participants. The data collected using an accelerometer (r = 0.835, p < 0.001) had the highest correlation as compared to that of the WorkE (r = 0.805, p < 0.001) and KineticE (r = 0.466, p < 0.001) correlations with the reference indirect calorimetry using Quark activity energy expenditure (QuarkAEE). The regression results show that KineticE and the weight of the participant were significant factors for mechanical energy prediction (AEEKinetic). However, according to the work prediction equation (AEEWork), only WorkE was significant. The new energy prediction models showed significant agreement with the standard QuarkAEE (AEEKinect, r = 0.641, p = 0.02; AEEWork, r = 0.793, p < 0.001), and they were comparable to accelerometer predictions (r = 0.682, p = 0.001). The findings indicate that Kinect can be a potentially viable alternative to measure energy expenditures. The models can be applied with higher accuracy, especially when the activity demands high body movements.

Respirator physiologic impact in persons with mild respiratory disease

OBJECTIVE

To assess whether mild respiratory disease affects physiologic adaptation to respirator use.

METHODS

The study compared the respiratory effects of dual cartridge half face mask and filtering facepeice (N95) respirators while performing simulated-work tasks. Subjects with mild chronic obstructive pulmonary disease (n = 14), asthma (n = 42), chronic rhinitis (n = 17), and normal respiratory status (n = 24) were studied. Mixed model regression analyses determined the effects of respirator type, disease status, and the respirator-disease interactions.

RESULTS

Respirator type significantly affected several physiologic measures. Respirator type effects differed among disease categories as shown by statistically significant interaction terms. Respiratory timing parameters were more affected than ventilatory volumes. In general, persons with asthma showed greater respirator-disease interactions than chronic obstructive pulmonary disease, rhinitis, or healthy subjects.

CONCLUSIONS

The effects of respirator type differ according to the category of respiratory disease.

Influence of inspiratory resistance on performance during graded exercise tests on a cycle ergometer

Due to more stringent requirements to protect personnel against hazardous gasses, the inspiratory resistance of the present generation of respiratory protective devices tends to increase. Therefore an important question is to what extent inspiratory resistance may increase without giving problems during physical work. In this study the effects of three levels (0.24; 1.4 and 8.3 kPa s l(-1)) of inspiratory resistance were tested on maximal voluntary performance. Nine male subjects performed a graded exercise test on a cycle ergometer with and without these three levels of inspiratory resistance. Oxygen consumption, heart rate, time to exhaustion and external work were measured. The results of these experiments showed that increasing inspiratory resistance led to a reduction of time to exhaustion (TTE) on a graded exercise test(GXT). Without inspiratory resistance the mean TTE was 11.9 min, the three levels of resistance gave the following mean TTE's: 10.7, 7.8 and 2.7 min. This study showed that TTE on a GXT can be predicted when physical fitness (VO2-max) of the subject and inspiratory resistance are known. The metabolic rate of the subjects was higher with inspiratory resistance, but no differences were found between the three selected inspiratory loads. Other breathing parameters as minute ventilation, tidal volume, expiration time and breathing frequency showed no or minor differences between the inspiratory resistances. The most important conclusion of these experiments is that the overall workload increases due to an increase in inspiratory resistance by wearing respiratory protective devices.

Effect of differing facial characteristics on breathing resistance inside a respirator mask

A group of subjects with a large range of facial characteristics was asked to breathe deeply while wearing a full facepiece respirator. The facial characteristics noted were head length, head depth, bizygomatic breadth, lip length, and Menton-Sellion length. External resistances to inhalation or exhalation were varied in each of the trials. The data collected were analyzed for possible correlation between facial characteristics and breathing resistance. Although respirator resistances were found to vary, no statistically significant correlation was found with anthropometric measurements.