Physiological reactions to heat of Bushmen and of unacclimatized and acclimatized Bantu

1964 ◽  
Vol 19 (5) ◽  
pp. 885-888 ◽  
Author(s):  
C. H. Wyndham ◽  
N. B. Strydom ◽  
J. S. Ward ◽  
J. F. Morrison ◽  
C. G. Williams ◽  
...  
Keyword(s):  
Physical Fitness ◽  
Ethnic Groups ◽  
Cold Exposure ◽  
Skinfold Thickness ◽  
Good Evidence ◽  
Heat Conductance ◽  
Heart Rates ◽  
Kalahari Desert ◽  
Cold Responses ◽  
Physiological Reactions

Bushmen in the Kalahari desert fulfill two criteria for acclimatization to heat. They exercise actively, in hunting, in relatively severe heat in midsummer. Compared with unacclimatized Bantu they have higher sweat rates per square meter and lower heart rates. However, rectal temperatures are not much lower than those of unacclimatized Bantu. River Bushmen present a paradoxical picture. In summer sweat rates are higher than in winter, but are not as high as desert Bushmen. Summer heart rates are, however, higher than in winter. Rectal temperatures in the two seasons are similar. The higher sweat rates in summer are good evidence of better acclimatization than in winter; the higher heart rates may be a reflection of differences in physical fitness in the two seasons. association of morphology and metabolism on cold exposure; cold responses of Bantu, Bushmen, and Caucasians; heat conductance and skinfold thickness in cold; metabolisms of Bantu, Bushmen, and Caucasians in cold; toe, finger, and rectal temperatures of different ethnic groups in cold Submitted on February 4, 1964

Acclimatization of Scottish Blackface sheep to cold. 2. Skin temperature, heart rate, respiration rate, shivering intensity and skinfold thickness

1968 ◽  
Vol 10 (1) ◽  
pp. 17-35 ◽  
Author(s):  
A. R. Sykes ◽  
J. Slee
Keyword(s):  
Heart Rate ◽  
Skin Temperature ◽  
Cold Exposure ◽  
Chronic Exposure ◽  
Physiological Responses ◽  
Skinfold Thickness ◽  
Acute Exposure ◽  
Heart Rates ◽  
Ambient Temperatures ◽  
Acute Cold Exposure

Closely shorn Scottish Blackface female sheep aged 9–14 months, half on high plane and half on low plane nutrition, were subjected, in climate chambers, to two short acute cold exposures down to −20°C. The acute exposures were separated by two weeks chronic exposure to a moderately subcriticai temperature (+8°C) or to a thermoneutral temperature (+30°C). Most of the sheep showed a greater resistance to body cooling at the second acute exposure (Slee and Sykes, 1967). This increased resistance to hypothermia, defined as acclimatization, was apparently influenced more by acute than by chronic cold exposure. The present paper deals with changes in skin temperature, heart rate, shivering intensity and skinfold thickness which also resulted from cold exposure, and accompanied acclimatization.After acute cold exposure followed by chronic exposure to +8°C the following changes in these parameters were observed:1. Extremity skin temperatures and heart rates were consistently increased at thermoneutral ambient temperatures.2. Vasoconstriction of the extremities and increased heart rate, both of which normally occur during the early stages of cold exposure, were delayed.3. Heart rates at sub-zero ambient temperatures were increased.4. Cold-induced vasodilatation at sub-zero ambient temperatures was increased.After acute cold treatment alone the intensity of shivering during the second acute exposure was reduced. Also the onset of foot vasoconstriction was slightly delayed.A highly significant relationship was observed between shivering intensity and heart rate during cold exposure.Plane of nutrition had less effect on the physiological responses to cooling than did previous cold experience.It was suggested in discussion that the physiological responses associated with acclimatization were: elevated basal metabolic rate, delayed onset of vasoconstriction and delayed metabolic response to cold, and consequent lowering of the critical temperature. Summit metabolism was also increased and shivering intensity reduced during acute cold exposure. Some of these responses could have resulted from either acute or chronic moderate cold exposure. However their persistence, once induced, appeared to depend upon continued exposure to moderate cold.

Heat reactions of male and female Caucasians

1965 ◽  
Vol 20 (3) ◽  
pp. 357-364 ◽  
Author(s):  
C. H. Wyndham ◽  
J. F. Morrison ◽  
C. G. Williams
Keyword(s):  
Sex Differences ◽  
Work Conditions ◽  
Work Rate ◽  
Air Velocity ◽  
Psychological Reactions ◽  
Male And Female ◽  
Heart Rates ◽  
Physiological Reactions

Thirty male and twenty-six female Caucasians were tested at work levels of 1.0 liters O2 consumption in 90 F wet-bulb temperature, 93 F dry-bulb temperature, and 80 ft/min air velocity for comparative heat reactions in the unacclimatized state. The females had more severe physiological and psychological reactions. Rectal temperatures of 104 F and heart rates of 180 beat/min were reached more rapidly than in the male. The females sweated less and their oxygen consumptions were lower than those of the males. Ten males and four females were then acclimatized to the same extent at the same work rate in 93 F wet-bulb temperature. At the end of the period their reactions were closely similar, although the females responded slower to the acclimatization procedure. Both groups ended with heart rates of 140 beat/min and rectal temperatures of 102 F. The females, however, continued to sweat less. In a retest at 90 F wet-bulb temperature, both groups had heart rates of 130–140 beat/min and rectal temperatures of 101 F. Females still sweated less. The results demonstrate the fact that females react more severely on exposure to severe heat and work conditions. Once acclimatized, however, the temperature and circulatory reactions of both sexes are closely similar, but the females sweat less than males. acclimatization of Caucasians to heat; Caucasians—acclimatization to heat; sex differences—heat reactions; physiological reactions to heat Submitted on September 14, 1964

Health-Related Physical Fitness Levels of Elementary School Children Ages 5–9

1992 ◽  
Vol 75 (3) ◽  
pp. 819-826 ◽  
Author(s):  
Holly R. Lehnhard ◽  
Robert A. Lehnhard ◽  
Stephen A. Butterfield ◽  
Donna M. Beckwith ◽  
Scott F. Marion
Keyword(s):  
Physical Fitness ◽  
Skinfold Thickness ◽  
School Age Children ◽  
School Students ◽  
Physical Fitness Test ◽  
Public School Students ◽  
Health Goals ◽  
Health Related ◽  
The One ◽  
Fitness Levels

National health goals include an increase in the physical activity and physical fitness of school-age children by the year 2000. To assess current fitness levels in the state of Maine, more than 8,000 public school students, ages five through nine, were assessed using a nationally known (American Alliance for Health, Physical Education, Recreation and Dance) health-related physical fitness test. Maine students were then compared with a national norm group on (1) the one-mile walk/run (minutes:seconds), (2) skinfold thickness (centimeters), (3) one-minute timed sit-ups (number performed correctly), and (4) the sit and reach test for flexibility (centimeters). Generally, Maine boys and girls scored higher than the norms on the sit-up, sit and reach, and one-mile walk/run; however, they had significantly larger skinfold thicknesses. Implications for assessment of health-related fitness in this age group were discussed.

SEASONAL ENERGY EXPENDITURES AND THERMOREGULATORY RESPONSES OF BISON AND CATTLE

1979 ◽  
Vol 59 (3) ◽  
pp. 611-617 ◽  
Author(s):  
R. J. CHRISTOPHERSON ◽  
R. J. HUDSON ◽  
M. K. CHRISTOPHERSEN
Keyword(s):  
Cold Exposure ◽  
Low Temperatures ◽  
Metabolic Rates ◽  
Heart Rates ◽  
Ambient Temperatures ◽  
Energy Expenditures ◽  
Thermoregulatory Responses ◽  
Air Temperatures ◽  
Wind Velocities

The metabolic rates of two bison and four Hereford spring-born calves were measured at monthly intervals from December until the following November. Following adaptation at seasonal ambient temperatures, metabolic measurements were made while calves were exposed to controlled temperatures of +10, 0 and −30 °C. Exposure of the Hereford calves to −30 °C resulted in increased metabolic rates during the first 6 mo of the study but the magnitude of the response was greatly attenuated as the calves grew larger. At −30 °C, bison calves either maintained or reduced metabolic rates compared to expenditures at +10 °C. When the calves were about 17 mo of age, they were exposed to a combination of low temperatures and wind. Wind velocities of 4.7 km∙h−1 did not influence metabolic rates of either bison or Herefords at air temperatures of 0 °C. However, at −30 °C, metabolic rates increased from 650 and 700 KJ∙kg−.75∙d−1 to 835 and 950 KJ∙kg−.75∙d−1 in Hereford and bison calves, respectively. Neither respiratory frequencies nor heart rates were influenced significantly during cold exposure, but heart rates increased in response to wind. In general, metabolic rates and heart rates were lower in bison calves.

Responses of cold-acclimatized men to infused norepinephrine

1963 ◽  
Vol 18 (6) ◽  
pp. 1209-1212 ◽  
Author(s):  
Robert J. T. Joy
Keyword(s):  
Oxygen Consumption ◽  
Cold Exposure ◽  
Nonshivering Thermogenesis ◽  
Drug Induced ◽  
Cold Acclimatization ◽  
Heart Rates ◽  
Before And After ◽  
Blood Pressures ◽  
Skin Temperatures ◽  
Healthy Males

Nine healthy males were infused with norepinephrine (o. μg/kg min) for 20 min before and after five 40-hr weeks of seminude exposure to 5 C. All infusions were given in the basal state, in a quiet room at 27 C, after a 30-min period of control measurements. Rectal temperatures and respiratory rates were unchanged either by the drug or the intervening cold exposure. The drug increased respiratory minute volumes and tidal volumes and decreased heart rates, but equally so in both experiments. Mean skin temperatures were unaffected by the drug but were significantly (P < .025) higher after cold exposure (mean 1 C). Both basal and drug-induced increase above basal of systolic and diastolic blood pressures was significantly lower (P < .025) after cold exposure. Oxygen consumption was the same in both basal periods and was unaffected by the drug before cold exposure. After cold exposure, norepinephrine produced a significant (P < .025) increase in oxygen consumption (mean 18 cc/min m2). These results show a changed sensitivity to norepinephrine in cold-exposed men, with a decrease in vasopressor response and the development of a calorigenic response. The data suggest that in men, norepinephrine may be a mediator of a nonshivering thermogenesis occurring with cold acclimatization. Note: (With the Assistance of Joseph C. Matone, Gerald W. Newcomb, and Wendell C. Bradford) cold exposure; catecholamines; norepinephrine calorigenesis; nonshivering thermogenesis Submitted on May 2, 1963

Physiological reactions to cold of Caucasian females

1964 ◽  
Vol 19 (5) ◽  
pp. 877-880 ◽  
Author(s):  
C. H. Wyndham ◽  
J. F. Morrison ◽  
C. G. Williams ◽  
G. A. G. Bredell ◽  
J. Peter ◽  
...  
Keyword(s):  
Air Temperature ◽  
Rectal Temperature ◽  
Metabolic Rates ◽  
Climatic Chamber ◽  
Finger Temperature ◽  
Air Temperatures ◽  
Applied Physiology ◽  
Cold Responses ◽  
Physiology Laboratory ◽  
Physiological Reactions

The physiological reactions to cold of nine female Caucasians were examined and compared with the reactions of a sample of male Caucasians. The experiment was conducted in the climatic chamber of the Applied Physiology Laboratory at air temperatures of 27 and 5 C, with a wind velocity of 80–100 ft/min. The sample of nine did not provide for intermediate temperature studies. The metabolic rates of the females were lower than those of the males, at both 27 and 5 C, but when expressed per square meter no differences were found. Finger and toe and rectal temperatures were the same for both sexes at 5 C, but the average female finger temperature was lower than that of the males at 27 C. The average female skin temperature was 2 C lower than that of the males. This indicates a greater subcutaneous insulation for females and this is confirmed by skinifold measurements. Both Caucasian sexes therefore display an increase in rectal temperature with fall in air temperature, which contrasts markedly with the Bantu and Bushman, both of whom show a decrease in rectal temperatures. Caucasian females and cold; cold responses of Caucasian females Submitted on September 17, 1963

scholarly journals Overweight or Obesity, Gender, and Age Influence on High School Students of the City of Toluca’s Physical Fitness

2017 ◽  
Vol 2017 ◽  
pp. 1-11 ◽  
Author(s):  
Flor de Maria Cruz Estrada ◽  
Patricia Tlatempa Sotelo ◽  
Roxana Valdes-Ramos ◽  
José Aldo Hernández Murúa ◽  
Rafael Manjarrez-Montes-de-Oca
Keyword(s):  
Physical Activity ◽  
High School Students ◽  
Physical Fitness ◽  
Skinfold Thickness ◽  
Normal Weight ◽  
Overweight And Obesity ◽  
School Students ◽  
Cross Sectional ◽  
Probabilistic Sampling ◽  
The City

Material and Method. This is a prospective, cross-sectional, and correlational study with a probabilistic sampling in which 150 teenagers from three different high schools from the city of Toluca, Mexico, aged 15–17, were assessed. Objective. To determine if weight, age, and gender have an influence on physical fitness evaluated with the EUROFIT and ALPHA-FITNESS batteries. Results. Women have a higher overweight and obesity rate than men (3 : 1). Adolescents who have normal weight have regular physical fitness (74.9%). When comparing genders we found that men have a higher mean than women in the tests, except for skinfold thickness and waist circumference. Age was only correlated with the plate tapping test (p=0.001). There are significant differences in the standing broad jump test and the Course-Navette of the EUROFIT and ALPHA-FITNESS batteries (p=0.000). Conclusions. It is likely that regular physical activity, and not normal weight, helps generate healthy physical fitness. Male subjects had a higher mean than women, reporting a better physical fitness and more frequent physical activity.

scholarly journals Tracking of Physical Activity, Physical Inactivity, and Health-Related Physical Fitness in Rural Youth

1999 ◽  
Vol 11 (4) ◽  
pp. 364-376 ◽  
Author(s):  
Russell R. Pate ◽  
Stewart G. Trost ◽  
Marsha Dowda ◽  
Alise E. Ott ◽  
Dianne S. Ward ◽  
...  
Keyword(s):  
Physical Activity ◽  
Physical Fitness ◽  
Vigorous Physical Activity ◽  
Intraclass Correlation ◽  
Correlation Coefficients ◽  
Skinfold Thickness ◽  
Rural Youth ◽  
Cycle Ergometer ◽  
After School ◽  
Fitness Measures

This study examined the tracking of selected measures of physical activity, inactivity, and fitness in a cohort of rural youth. Students (N = 181, 54.7% female, 63.5% African American) completed test batteries during their fifth- (age = 10.7 ± 0.7 years), sixth-, and seventh-grade years. The Previous Day Physical Activity Recall (PDPAR) was used to assess 30-min blocks of vigorous physical activity (VPA), moderate-to-vigorous physical activity (MVPA), TV watching and other sedentary activities, and estimated energy expenditure (EE). Fitness measures included the PWC 170 cycle ergometer test, strength tests, tnceps skinfold thickness, and BMI. Intraclass correlation coefficients (ICCs) for VPA, MVPA, and after-school EE ranged from 0.63 to 0.78. ICCs ranged from 0.49 to 0.71 for measures of inactivity and from 0.78 to 0.82 for the fitness measures. These results indicate that measures of physical activity, inactivity, and physical fitness tend to track during the transition from elementary to middle school.

scholarly journals Variation in physical fitness between ethnic groups in nine year olds

1999 ◽  
Vol 28 (2) ◽  
pp. 281-286 ◽  
Author(s):  
H. Bettiol ◽  
R. J. Rona ◽  
S. Chinn
Keyword(s):  
Physical Fitness ◽  
Ethnic Groups

scholarly journals Physiological reactions to fear provocation in dogs

2004 ◽  
Vol 180 (3) ◽  
pp. 439-448 ◽  
Author(s):  
E Hydbring-Sandberg ◽  
LW von Walter ◽  
K Hoglund ◽  
K Svartberg ◽  
L Swenson ◽  
...  
Keyword(s):  
Heart Rate ◽  
Plasma Cortisol ◽  
Plasma Concentrations ◽  
Behavioral Problem ◽  
Heart Rates ◽  
Physiological Variables ◽  
Beta Endorphins ◽  
The Individual ◽  
Physiological Reactions ◽  
Privately Owned

Fear is a common behavioral problem in dogs. In this paper, we studied the association between behavioral and physiological responses in two potentially fear-eliciting situations. The aim was to establish whether it is possible to separate dogs of the collie breed that are fearful of floors and gunshots from those that are not by studying changes in heart rate and hematocrit, plasma cortisol, progesterone, testosterone, vasopressin, and beta-endorphin concentrations. Thirteen privately owned male dogs of the collie breed were studied during a floor test, using different types of floors, and a subsequent gunshot test. Seven of the dogs were identified as being fearful of floors and six were declared as fearless. Out of the 13 dogs, seven were fearful of gunshots and six were fearless of gunshots. Since fear of floors did not always occur concomitantly with fear of gunshots, there were consequently four different groups of dogs. The heart rate increased during the floor test in all groups, but dogs that were fearful of floors had higher heart rates than dogs that were fearless of floors. Dogs that were fearful of gunshots had higher heart rates, higher hematocrit levels and higher plasma concentrations of cortisol, progesterone, vasopressin, and beta-endorphins during the gunshot test than did dogs that were found to be fearless of gunshots. Plasma cortisol and progesterone increased drastically during the gunshot test in dogs identified as being fearful of gunshots. In fearful dogs, the testosterone concentration increased after completion of the floor test and before the gunshot test started, but there were no significant differences in testosterone between the groups. Since dogs fearful of gunshots had increased levels of several physiological parameters, the results demonstrated that this fear is a serious stress for the individual, a fear which it is possible to register with physiological variables.

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