Search PubMed⌕ Search

Biomedical subjects

M Pafnote

Publications and source records attributed to M Pafnote.

14 recordsLinked to original sources
PubMedDate not supplied

Cortical control of sinus arrhythmia in man studied by spectral analysis.

Eighteen healthy male volunteers, 21-26 years old, participated in a study intended to detect cortical control of beat-to-beat heart rate variability independent of the effects on breathing and mean heart rate. They were tested while seated and standing relaxed (baseline), and while performing tasks requiring concentrated attention while sitting. The mental concentration elicited a typical cardiorespiratory response manifested by moderate acceleration and shallowing of respiration with a small increase of mean heart rate (HR), a pattern already widely acknowledged as typically associated with concentration. With the aid of a variable tone delivered to the ear as a guide, the subjects were trained to breathe at the same rate without concentrating in order to test the influence of respiration on the concentration pattern. ECG, thermistor pneumogram and ear-lobe photo-plethysmogram were recorded and data reduction was performed on 3 minute or 1 minute data sequences selected for the best steady-state. Statistical treatment was limited to a subgroup of 10 subjects in whom there was no overlapping of the spectra of respiratory and Traube-Hering-Mayer sinus arrhythmia (RSA and THM-SA, respectively). Mental concentration elicited significant depression of both RSA and THM-SA even if the respiratory parameters were kept constant.

Adult↗
PubMedDate not supplied

Physical fitness in different groups of industrial workers.

Maximum oxygen consumption was determined by the indirect method (with submaximal effort) in 155 forestry workers, 120 miners, 240 tool manufacturers (turners, planers etc.), 75 control-board operators. Differences were found according both to age and occupation. Variance analysis showed that age had a greater impact (F = 68) than occupation (F = 20). The highest values were recorded in foresters (57 -- 39 ml/kg/min depending on age). In miners the average values were 49 -- 35 ml/kg/min, while toolmakers and pannel operators showed maximum oxygen consumption of 45 -- 32 ml/kg/min, VO2 being nearly the same in both groups of occupation for the respective groups of age. Values of 50 ml/kg/min or above were found in 88% of 20 -- 29 year -old foresters and in 54% of the miners, while in toolmakers and in pannel operators such vales of VO2 were found only in 37% and 27% respectively, of the cases.

Adolescent↗
PubMedDate not supplied

Physical work load in modern mining.

Following our Institute's involvement in the physiology of mining work (since 1953), this paper deals with underground work load investigated in terms of time, energy expenditure and heart rate in coal miners working with various types and degrees of mechanization. Results showed that a chamber coal face and at heading (coal or sterile rock) mechanization of haulage and loading (conveyor belt and loading machine) led to 50 -- 100 kcal reduction of energy expenditure/hour. At longwall faces, mechanization of haulage (by conveyor) or hewing and loading (with drum-combine) shortened shoveling time, while there was an increase of manual work in the tasks of supporting which was conducive to metabolic rates of 300 kcal/hour. In the case of fully mechanized coal working, including supporting, there was a significant decrease of energy expenditure.

Adult↗