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4 Nutrient Metabolism and Physical Activity
Pages 125-142

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From page 125...
... Resting or Basal Energy Requirements Many investigators have attempted to confirm the estimated energy requirement for pregnancy by measuring the Nero major components of energy expenditure: resting metabolism and energy expenditure during 125
From page 126...
... The unsupplemented women, who consumed only i,500 kcalJday, had lower Roars in the second and third trimesters than did the women who received supplements and consumed about 1,950 kcal/day (Lawrence et al., 1984; Prentice et al., 1983~. The supplemented women required an additional 13,000 kcal for resting metabolism; only 1,000 kcal were required by the unsupplemented women (Table 4-1~.
From page 127...
... Although studies of the energy expenditure of pregnant women who regularly take part in recreational activities have not been done, one group of investigators reported that ~e' energy intakes of women who jog throughout their pregnancies are similar to those reported by sedentary pregnant women studied previously (Slavic et al., 1985~. There is some evidence that physical activity mproves the efficiency of energy use in nonpregnant women (King and Butterfield, 1986)
From page 128...
... 128 ~ - lo to ce _ ~ 0 0 - o ~ ~ ~ ~ ~ E ~ ~ ~r 8 ~ ~ ~=o ~ o ~ ~ ~ o ~ _ o, ~ ~ ~ o~ _ ~__ ~ ~ E ~ ~ o i~ .E _' _ C)
From page 129...
... 129 o te v ~C5 Cd e.
From page 130...
... Among agricultural workers in developing countnes, there are seasonal changes in the food supply and physical wore In The Gambia during the wet season, when more people go hungry, agricultural work is Beater than during the dry season, when people usually have adequate food supplies. Changes in body weight indicate that pregnant and lactating women are in a negative energy balance during the wet-hungry season and in a positive energy balance during the dry-fed season (Prentice, 1984~.
From page 131...
... Since Sue use of glucose is increased during exercise, maternal glucose levels in blood fall and may thereby limit the fetal glucose supply. In late pregnancy, glucose concentrations ~ blood fall with short-term exercise of moderate Utensil (Gorski, 1985)
From page 132...
... To ensure the replacement of maternal glycogen stores, it may be prudent for physically active pregnant women to consume a diet high in complex carbohydrates following a period of exera set This would allow an adequate supply of glycogen for the maintenance of maternal glucose levels in blood and the fetal glucose supply during short-te}m or overnight fasts. PROTEIN Pregnant women retain about 6-8 g of protein (1-1.3 g of nitrogen)
From page 133...
... LunitM dam from "mars suggest that some Unease in VO2-max is possible with physical training, particularly if the training begins before pregmangy. Pregnancy also appears to increase the biological work necessary to accomplish physical work, through increases in both total mass and respiratory wore Upper body physical activity at the same work load in pregnant aIld nonpregnant women appears to increase the VO2-max to similar degrees, while treadmill exercise involving the locomotion of graved women appears to require more energy ~ pregnant than nonpregnant women, perhaps because of the larger mass carried by pregnant women.
From page 134...
... It is about double dig treadmill exercise at about 2-3 times the RMR (Levity et al., 1982~. Hormonal Changes Maternal hormonal responses to physical activity have received comparatively little attention, but in general, they appear to resemble the changes observed with acute stress.
From page 135...
... Although there is some difference in the responses of acutely versus chronically restricted dams, results of these two studies indicate that when food is restricted during gestation, a dam spares her own tissue at the cost of the fetus. Only limited information is available regarding the ejects of maternal physical activity on the fetus.
From page 136...
... EllECIS OF tJNDERNUIRITION ON PHYSICAL AClIVIlY Physical activity influences nutritional status and the requirements for nutnents. Individuals who regularly perform strenuous work have a higher requirement for energy than do similar individuals doing sedentary worm Conversely, the nutritional status of an individual influences his or her capacity to do worm Individuals with a reduced weight-for-height often have a compromised muscle mass and a reduced capacity to perform certain types of physical work Also, small stature, whether due to poor nutrition during the growing years or other causes, may reduce the capacity to perform certain types of physical work later In life.
From page 137...
... Time-motion studies measure energy expenditure and the contribution of physical activity to it; they may or may not be coupled to measurements of productivity ~ which the type of task completed and the amount of time to complete a task are reported. These studies are generally done in individuals who perform agricultural or construction worm Although impaired productivity has been documented in chronically undernourished adult male and female populations (Edmondson, 1977; Viten, 1971; Viten and Torun, 1974; Wolgemuth, 1982)
From page 138...
... Those workers who received a 250~kcal supplement daily used their si=a to work at home, wale around tOwD, or play football, while flee unsupplemented workers rested or slept. Both groups of workers took the same amount of time to get to work each morning, but the unsupplemented workers rested more frequently on their way home from wore In a group of healthy young men from a graduate theological seaway in California, a 500 kcal/day reduction in food intake was associated with a change in physical activity (Gorsky and Calloway, 1983~.
From page 139...
... 1976a. Basal metabolic rate and work energy expenditure of mature, pregnant women.
From page 140...
... 1983. Energy expenditure of pregnant women at rest or waling self-paced.
From page 141...
... 1984. Physical activity, nutritional status, and physical work capacity in relation to agncultural produc~vi~.


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