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Biomedical subjects

Y Shapiro

Publications and source records attributed to Y Shapiro.

At least 73 records · Page 4Linked to original sources
PubMed1985

Effect of food intake on exercise fatigue in trained and untrained subjects.

The effects of carbohydrate and fat intake on exercise-induced fatigue was investigated in 30 untrained--(VO2max of 40.6 +/- 2.7 ml X kg-1 X min-1) and 24 trained-subjects (VO2max of 52.3 +/- 2.7 ml X kg-1 X min-1) performing a 34 km march with a 25 kg backpack. Marching time was 8 1/2 h and 6 1/3 h in the untrained and trained-subjects respectively. The subjects were divided into 3 dietary groups. One group had free access to sugar cubes, the second group was offered almonds and the third one served as a control. Triglyceride levels decreased by 65 mg X dl-1 in untrained, and by 115 mg X dl-1 in trained subjects, while blood glucose remained at normal levels. In the untrained subjects, ingestion of almonds delayed the subjective sensation of exhaustion, while 50% of the controls and the sugar consuming subjects complained of exhaustion. The data suggest that ingestion of food containing fat delays exercise induced exhaustion or fatigue to a greater extent than does carbohydrate ingestion.

Adolescent↗
PubMed1985

Fatal heatstroke after a short march at night: a case report.

A case of heatstroke is reported in a young recruit who participated in a 4-km march at night. Body temperature was not measured at the time of collapse. Hyperventilation and aggressive behavior misled to the incorrect diagnosis of hysteric reaction. Upon arrival at the Medical Center 4h later, the patient experienced deep coma, renal failure, shock, and uncontrolled bleeding. Inspite of intensive treatment, the patient died 27 h after collapse. A positive blood culture suggests the involvement of septicemia in the fulminant picture of the disease. The importance of immediate measurement of rectal temperature in any case of collapse after exercise is emphasized.

Adolescent↗
PubMed1984

Significance of bone scintigraphy in symptomatic spondylolysis.

In a prospective study, the authors evaluated the usefulness of bone scintigraphy in the work-up of young military personnel with lumbar spondylolysis and persistent low back pain. Ten out of 23 spondylolytic individuals with a recent history of low back pain had positive scintigrams, and none of a group of painless spondylolytic individuals had positive scans. We believe these results indicate that bone scintigraphy is of value in determining whether a spondylolysis in a young individual can be attributed to recent physical exertion or a specific recent traumatic incident.

Adult↗
PubMed1983

Cardio-respiratory physical training in water and on land.

Fifteen unconditioned young men, who were similar in maximal aerobic power (VO2 max), were divided into three groups (n = 5 each) and physically trained for one month on a cycle ergometer either on land (I) or immersed to the neck in water of either 32 degrees C (II) or 20 degrees C (III) to determine if physical training (PT) in water and air differ. PT consisted of one-hour daily exercise, 5 times/wk, with exercise intensity readjusted each week to maintain a constant training stimulus of approximately 75% VO2 max (determined on land). Throughout the training period, heart rates (fc) of III averaged 20 and 10 beats . min-1 less than I and II, respectively, despite working at the same VO2 and % VO2 max. Training elicited a 16% increase in VO2 max in I compared to increases of 13 and 15% for II and III, respectively. It was concluded that PT in water produces similar physiological adaptations as does training on land. In cold water, VO2 max is improved despite training with fc significantly lower than that on land.

Adult↗
PubMed1983

Does heat acclimation lower the rate of metabolism elicited by muscular exercise?

Heat acclimation has been suggested to either lower or have no effect on the rate of metabolism (M) elicited by muscular exercise. The purpose of the present investigation (Study I) was to examine the effect heat acclimation has on the M (W . kg-1 or VO2 in ml . kg-1 . min-1) elicited by muscular exercise. Two additional investigations were evaluated to determine if season (summer or winter) of year (Study II) and subject gender (Study III) further influence the effect heat acclimation has on M during exercise. Volunteers for Study I (n = 15 men), II (n = 8 men), and III (n = 10 men and 9 women) completed standardized treadmill walks in hot (40 degrees C, 30% rh or 49 degrees C, 20% rh) and cool (20 degrees C, 40% rh) environments immediately before and after heat acclimation. After heat acclimation, a lower M was observed for Study I (-4%; p less than 0.05), II (-2%; N.S.) and III (-3%; p = 0.06) in the hot environments. In addition, after heat acclimation a lower M was observed for Study I (-3%; p = 0.08), II (-5%; p less than 0.05) and III (-6%; p less than 0.05) in the cool environment. Season of year and subject gender did not have a significant effect on these results. These data indicate that heat acclimation does lower the M elicited by exercise. The observed percent decrease was lower in the hot (-3%) than cool (-5%) test environments.

Acclimatization↗
PubMed1982

The effect of salt loading diet on the intraocular pressure.

Salt tablets are habitually ingested by some people while doing physical exercise in hot climate, in order to prevent sodium depletion. The effects of supplementary salt on the intraocular pressure was investigated on 5 healthy acclimatized subjects who rode a bicycle ergometer at temperature of 35 degrees C and relative humidity of 40%. A significant decrease of 1.0 mmHg in their mean intraocular pressure was detected when 10.2 gm NaCl was added daily to the normal diet. The pressure reduction was associated with changes of the body fluid balance.

Adult↗
PubMed1982

Thermoregulatory responses of patients with extensive healed burns.

Two groups (A, n = 4; B, n = 6) of young male subjects with deep second- and third-degree healed burns (burned area: 48.6 +/- 3.6 and 23.7 +/- 3.1% of the total skin surface area in groups A and B, respectively) and a group of healthy subjects (C, n = 10) underwent a 3-h exposure to 40 degrees C, 50% rh, stepping on a bench 32 cm high, at a rate of 12 steps/min (Vo2 = 1.05 +/- 0.06 l X min-1). Rectal temperature (Tre), mean skin temperature (Tsk), and heart rate (HR) of group A were significantly higher than those of groups B and C; i.e., at the end of the 1st h Tre was 38.7, 37.9, and 37.7 degrees C; Tsk was 37.3, 36.4, and 37.0 degrees C; HR was 151, 105, and 110 beats X min-1 in groups A, B and C respectively. Maximal evaporative cooling capacity (Emax) was 4.9 +/- 0.1, 7.2 +/- 0.5, and 10.2 +/- 0.4 W X kg-1 in groups A, B and C, respectively, while the required evaporation capacity for thermoequilibrium (Ereq) was similar in all groups (6.7 +/- 0.1, 6.8 +/- 0.1, and 6.6 +/- 0.1 W X kg-1). Total sweat rate (msw) was 594 +/- 13, 602 +/- 29, and 485 +/- 34 g X h-1 in groups A, B and C, respectively, msw normalized to healthy skin area (msw/AH) was 671 +/- 75, 449 +/- 29, and 280 +/- 16 g X h-1 X m-2 in groups A, B and C, respectively. Sweating sensitivity normalized to healthy skin area (msw/AH X delta Tre) was similar in all three groups. It is suggested that the similarity between groups B and C can be explained by the compensatory sweating from the healthy skin of group B, which was sufficient because Emax greater than Ereq. In group A, Emax less than Ereq; therefore thermoequilibrium could not be maintained despite high compensatory sweat rate from the healthy skin. The similarity in msw/AH X delta Tre supports the assumption that elevation in Tre is the main drive of sweat regulation and that sweat rate is a function of delta Tre and healthy skin surface area.

Adult↗
PubMed1982

Effects on heat tolerance of physical training in water and on land.

A 4-wk training program was undertaken by 15 untrained non-heat-acclimated males who were divided into three groups matched on maximal aerobic capacity (VO2max) and trained either in water or on land to determine how physical training (PT) in these different media affects heat tolerance. Subjects trained on a cycle ergometer for 1 h/day, 5 days/wk at 75% VO2max, with the exercise intensity progressively increased to maintain a constant training stimulus. Group I exercised on land, whereas groups II and III exercised while immersed to the neck in water of either 32 degrees C (II) or 20 degrees C (III). Daily exercise increased core temperature (Tc) in groups I and II but not in group III. Training elicited similar increases (approximately 15%) in VO2max in the three groups. Before and after PT, all subjects exercised at approximately 30% VO2max for 3 h at 49 degrees C, 20% rh. Compared with before training, groups I and II showed a decrease in final Tc and heart rate (HR) in the posttraining heat exposure. Sweat rate increased 25% in group II but remained the same in group I. Group III demonstrated a decrease in final HR, but final Tc was higher than before training. Sweat rate did not increase in group III and was lower than the other groups. It was concluded that PT can improve the cardiovascular response to dry heat without affecting thermoregulatory capacity. PT appears to enhance heat tolerance only if Tc is permitted to rise during exercise, thus stimulating the temperature-regulating center for heat dissipation.

Adaptation, Physiological↗
PubMed1982

Auxiliary cooling: comparison of air-cooled vs. water-cooled vests in hot-dry and hot-wet environments.

Water-cooled, air-cooled, and ambient air-ventilated auxiliary cooling vests were evaluated in a hot-wet climate (HW) (35 degrees C, 75% R.H.) and a hot-dry environment (HD) with additional infrared radiation (Ta = 49 degrees C, 20% R.H., 68 degrees C black globe temperature). Twelve subjects dressed in full chemical warfare combat uniforms underwent 120 min of heat exposure in each combination of climate and cooling vest, except for the hot-dry environment and ambient-air vest. During each exposure, total exercise time was 20 min and rest time 100 min. This resulted in a mean time weighted metabolic rate of 180 W. Both water-cooled and air-cooled vests were sufficient for cooling in the HW climate: heat storage (delta S) was 13 and 7 W, final rectal temperature (Tre) 37.4 and 37.3 degrees C, and heart rate (HR) 124 and 112 b . min-1, respectively. While using the ambient-air vest, all variables were significantly (p less than 0.05) higher (delta S, 25 W; Tre, 37.7 degrees C; HR, 139 b . min-1; respectively). In the HD climate, both water and air-cooled vests were insufficient with a delta S of 46 and 48 W, final Tre of 38.4 and 38.3 degrees C, and final HR of 151 and 147 b . min-1. However, both cooling vests improved the subjects' physiological status compared to these predicted variables without auxiliary cooling. No significant differences were found between the air or the water-cooled vests in either the HD or HW climates. It was concluded that an air-cooled vest can be used with the same efficiency as a water-cooled vest. In contrast, the ambient-air vest was shown to have a low effectiveness in HW and to be dangerous in a HD climate.

Body Temperature Regulation↗
PubMed1981

Way of life as a determinant of physical fitness.

Four hundred and five urbanites and 302 communal agricultural settlement (Kibbutz) members participated in a study which examined their physical fitness. The subjects were divided into three subgroups according to age: 18-21 years, 22-30 years, and 31-40 years. No differences were found among the two populations in all three subgroups as concerns anthropometric data. In the youngest age group no differences in resting heart rate and VO2 max between urbanites and kibbutz dwellers were found. For those aged over 21 years the VO2 max (40.8 +/- 10.0 ml O2/kg body weight/min for those aged 22-30 years and 38.7 +/- 9.7 ml O2/kg body weight/min for those aged 31-40 years) was significantly higher (p less than 0.001) than that of the urbanites (35.6 +/- 7.0 for age 22-30 and 33.1 +/- 8.0 ml O2/kg body weight/min for age 31-40 years). The results confirm the notion that physical fitness is a good profile of habitual activity.

Activities of Daily Living↗
PubMed1981

Heat tolerance in patients with extensive healed burns.

Some thermoregulatory parameters of 10 subjects with healed burns were studied. The subjects, 4 of whom had healed burns of over 40 percent (group A) and 6 with burns smaller than 30 percent (group B) were assigned in a climatic chamber to 3 hours bench stepping (30 cm height) under 40 degrees C and 50 percent relative humidity. Rectal temperature, weighted skin temperature, heat storage, and heart rate were all found to be significantly higher in group A than in group B or group C (control group of normal subjects). No significant difference was observed between groups B and C. A highly significant linear correlation (r = 0.89) was found between the sweat rate and percentage of burned area. In addition, 3 subjects of group A terminated the study after less than 90 minutes. Two subjects in group B terminated the study after 120 and 135 minutes, while all subjects of group C finished the entire 3 hour work. The study indicates that subjects with burns of over 40 percent could be classified as heat intolerant due to a pronounced reduction in perspiration area.

Adult↗
PubMed1981

Modification of the Monark bicycle ergometer for underwater exercise.

A standard Monark bicycle ergometer was modified for underwater exercise by removal of the friction belt and attachment of one to six metal fins to the flywheel. Three fins could be fastened to either side of the flywheel. The fins used on the left side of the wheel were made of standard perforated angle iron with the perpendicular side measuring 38 mm; those on the right side were made from the same length of nonperforated angle iron but with a perpendicular side of only 26 mm. Net surface area of the two types of fins (excluding area of perforation) was the same. Oxygen uptake (VO2) was found to be: VO2 = a(rpm)b + 0.25, 1.min-1, with a = 0.00164 -- 0.00104n + 0.000266n2 -- 0.00002n3; b = 1.64 + 0.506n -- 0.104n2 + 0.00667n3, when n is the number of fins. The correlation coefficient (r) between measured and predicted VO2 was r = 0.98. The preferable range of pedaling speeds was 29-40 rpm to maintain a constant speed for up to 1 h. Major advantages of this modified ergometer for underwater exercise are 1) the modification is simple and the same ergometer can be used for land exercise, 2) the ergometer can be biologically calibrated and used for a wide range of exercise oxygen uptakes, and 3) subjects can perform for a proportionally longer time period than other modifications of the same ergometer.

Adult↗
PubMed1981

Physiological and hematologic responses to summer and winter dry-heat acclimation.

Differences between acclimation to heat at the end of winter (W) and at the end of summer (S) were studied on the same eight male volunteers. Subjects were exposed to 40 degrees C, 30% rh for 10 consecutive days on two separate occasions approximately 5 mo apart (S and W). Daily exposures lasted 120 min: 10 min rest, 50 min walking 1.34 m . s-1 on the level, 10 min rest, 50 min walking. During W acclimation, rectal temperature (Tre) and heart rate (HR) decreased, sweat rate (msw) remained unchanged, and plasma and red cell volume of the blood expanded. During S acclimation, HR decreased while Tre and msw remained unchanged, and plasma volume increased. The Tre of the acclimated subjects remained higher in W, and the msw lower, than in S. It was concluded that acclimation does not totally eliminate the seasonal differences in thermoregulatory set point and sweating sensitivity. Further, acclimation to a more severe heat did not lower the thermoregulatory set point that was achieved by natural acclimatization to a milder heat but affected the cardiovascular adjustment and caused greater plasma volume expansion. W acclimation caused both plasma and blood cell volume expansion, whereas S acclimation affected only plasma volume.

Acclimatization↗
PubMed1981

The relationship between body temperature and intraocular pressure.

A comparison of the intraocular pressures of well-hydrated nonacclimatized and acclimatized subjects during submaximal work load in a hot environment was made. This comparison attempts to eliminate all possible influences on IOP, except body temperature. A direct relationship between the IOP and rectal temperature is postulated.

Acclimatization↗