Biomedical subjects

J Smolander

Publications and source records attributed to J Smolander.

42 records · Page 3Linked to original sources

PubMed1985

Laser-Doppler and plethysmographic skin blood flow during exercise and during acute heat stress in the sauna.

Forearm skin blood flow was measured in six male subjects by laser-Doppler flowmetry (LDF) and venous occlusion plethysmography (VOP) during constant-load (125-200 W) upright bicycle exercise in a warm environment (X + SD, ta 34.6 +/- 0.2 degrees C) and during a 15 min sauna bath (ta 69.0 +/- 2.8 degrees C). During the sauna test the LDF values correlated well with the VOP measurements in the initial phase of active cutaneous vasodilation, after which the LDF values almost leveled off in spite of a steady increase in VOP measurements. During the exercise the mean VOP and LDF values rose in parallel with each other to steady state levels. The relationship between the results of the two methods proved to be nonlinear. It was concluded that different parameters were measured by VOP and LDF. The latter measured mainly the integrated velocity of blood flow in the outermost cutaneous tissue, and this velocity seemed to be partly dependent on the level of the arterial inflow (VOP), but also on the prevailing pressure-flow and pressure-volume relations in the cutaneous vascular bed.

Adult↗

PubMed1985

Physiological strain in work with gas protective clothing at low ambient temperature.

Wearing an impermeable gas protective suit (Dräger 500 or 600) and a self-contained breathing apparatus (Dräger PA 80; total weight 27 kg (59.5 lb], seven experienced firemen and one mechanic performed simulated repair and rescue tasks in a chemical plant. The subjects' mean (+/- SD) age, height, weight and estimated maximal oxygen consumption were: 36 +/- 4 years; 181 +/- 6 cm; 83 +/- 8 kg; and 42 +/- 5 mL/min/kg, respectively. The operations took place outdoors (ambient temperature 2.0 degrees C (35.6 degrees F), wind velocity 0-4 m/s). The total work time averaged 37 minutes. During tasks of search, handling vents, and sawing and replacing bolts, the mean (+/- SE) heart rates measured by a Depex recording device were 146 +/- 2, 148 +/- 2, and 147 +/- 5 beats/min, respectively. The mean rectal temperature increased 0.8 degrees C during the whole work period. Weight loss due to sweat averaged 300 g. In conclusion, typical tasks with gas protective clothing caused marked physiological strain among subjects in average physical condition even though the thermal strain was relatively low because the weather was cool. The results emphasized the need to evaluate physical fitness during the periodic check-ups of workers who may have to use gas protective clothing.

Adult↗

PubMed1985

Effects of an SCBA on breathing pattern, gas exchange, and heart rate during exercise.

The effects of a pressure demand-type self-contained breathing apparatus (SCBA) (total weight, 15.5 kg) on breathing pattern, gas exchange, and heart rate were studied in 13 firemen. The subjects performed sequential progressive exercise tests on a treadmill both without and with an SCBA. The use of an SCBA consistently limited tidal volume. During submaximal exercise oxygen consumption and heart rate increased remarkably more with the SCBA than without it. Four subjects reached their maximal heart rate with the SCBA. Their mean ventilation rate was 68% and oxygen consumption was 83% of the maximal values attained without the SCBA. The shoulder harness of the heavy SCBA prevented free motion of the thorax, affecting the regulation of breathing, and thus seriously disturbed ventilation and gas exchange, particularly at heavier exercise levels.

Adult↗

PubMed1984

Policemen's physical fitness in relation to the frequency of leisure-time physical exercise.

Ninety to ninety-five men (aged 27 to 46 years) from the police academy were the study subjects. Their prior habits of physical exercise, estimated aerobic capacity (VO2max), muscular performance, and thickness of subcutaneous fat were determined. The policemen were taller (181 cm vs 175 cm) and heavier (84 kg vs 74 kg) than the average 20- to 40-year-old Finnish man, and their VO2max (1 X min-1) was higher (3.41 1 X min-1 vs 2.96 1 X min-1). The frequency of prior physical exercise significantly correlated with most of the variables studied. Those policemen who did not exercise at all (n = 12) were inferior to the average 20- to 40-year-old Finnish man on all the physical fitness tests, whereas the results of the most active policemen (n = 23) were clearly higher. The results indicate that the selection of heavier and taller men for police training guarantees a certain absolute level of physical performance capacity. However, the physical activity involved in police work is insufficient to maintain a high level of physical fitness, which must be achieved through participation in regular and effective physical training.

Adult↗

PubMed1984

Cardiorespiratory and thermal effects of wearing gas protective clothing.

Six healthy men aged 25 to 37 walked on a treadmill at work levels of 21 and 41% of their VO2max for 25 to 30 min wearing gas protective clothing (GPC) consisting of an impermeable suit with a self-contained breathing apparatus (total weight 25 kg) or shorts (control tests, CT) in a temperate environment (ta 24.3 degrees C +/- 1.0 degrees C, rh 30-50%). When the GPC was worn at 21 and 41% VO2max, the most prominent increases, compared with the CT, were noted in the heart rate (means +/- SE, 120 +/- 5 vs 76 +/- 3 beats min-1 and 171 +/- 5 vs 103 +/- 3 beats min-1), mean skin temperature (36.1 +/- 0.2 vs 31.3 degrees C +/- 0.1 degree C and 36.9 +/- 0.3 vs 30.9 degrees C +/- 0.4 degrees C) and sweat rate (473 +/- 51 vs 70 +/- 23 g m-2 h-1 and 766 +/- 81 vs 135 +/- 18 g m-2 h-1) indicating a high cardiovascular and thermoregulatory strain, which was not decreased by ventilating the suit with an air flow of 281 min-1 at 41% VO2max. The ventilation, oxygen consumption and production of carbon dioxide increased in relation to the extra weight of the GPC, partly dependent on the dynamic work level. It was concluded that the increase in the physiological load caused by the GPC was so high that the work-rest regimens, workers' level of physical fitness, cardiovascular health and heat tolerance should be considered whenever gas protective clothing is used.

Adult↗

PubMed1984

Reduction of isometric muscle endurance after wearing impermeable gas protective clothing.

The isometric endurance of forearm muscles at 40% maximum voluntary contraction was measured in six healthy male subjects, after they had walked for 25-30 min on a treadmill while wearing an impermeable gas protective suit and a self-contained breathing apparatus at a light (21% VO2 max), and a moderate 41% VO2 max) work level. The mean endurance times were 12% (NS) and 24% (P less than 0.01) shorter than the average control value after exercise for the light and moderate work levels, respectively. These changes were accompanied by an increased heart rate, and rectal and skin temperatures. Ventilating the suit with an air flow of 181 . min-1 at the moderate work level did not significantly affect isometric endurance (decreased 27%), heart rate or body temperatures. It was concluded, that muscular performance capacity is reduced after wearing gas-protective clothing in a temperate environment, presumably due to the increased muscle temperature, and this should be considered in scheduling work times and rest periods.

Adult↗