206 research outputs found
Thermal and circulatory responses during exercise: effects of hypohydration, dehydration, and water intake
No full text Armstrong, Lawrence E., Carl M. Maresh, Catherine V. Gabaree, Jay R. Hoffman, Stavros A. Kavouras, Robert W. Kenefick, John W. Castellani, and Lynn E. Ahlquist. Thermal and circulatory responses during exercise: effects of hypohydration, dehydration, and water intake. J. Appl. Physiol. 82(6): 2028–2035, 1997.—This investigation examined the distinct and interactive effects of initial hydration state, exercise-induced dehydration, and water rehydration in a hot environment. On four occasions, 10 men performed a 90-min heat stress test (treadmill walking at 5.6 km/h, 5% grade, 33°C, 56% relative humidity). These heat stress tests differed in pretest hydration [2 euhydrated (EU) and 2 hypohydrated (HY) trials] and water intake during exercise [2 water ad libitum (W) and 2 no water (NW) trials]. HY + NW indicated greater physiological strain than all other trials ( P < 0.05–0.001) in heart rate, plasma osmolality (Posm), sweat sensitivity (g / °C ⋅ min), and rectal temperature. Unexpectedly, final HY + W and EU + W responses for rectal temperature, heart rate, and Posm were similar, despite the initial 3.9 ± 0.2% hypohydration in HY + W. We concluded that differences in pretest Posm (295 ± 7 and 287 ± 5 mosmol/kg for HY + W and EU + W, respectively) resulted in greater water consumption (1.65 and 0.31 liter for HY + W and EU + W, respectively), no voluntary dehydration (0.9% body mass increase), and attenuated thermal and circulatory strain during HY + W. </jats:p
Intravenous vs. oral rehydration: effects on subsequent exercise-heat stress
No full text Castellani, John W., Carl M. Maresh, Lawrence E. Armstrong, Robert W. Kenefick, Deborah Riebe, Marcos Echegaray, Douglas Casa, and V. Daniel Castracane. Intravenous vs. oral rehydration: effects on subsequent exercise-heat stress. J. Appl. Physiol. 82(3): 799–806, 1997.—This study compared the influence of intravenous vs. oral rehydration after exercise-induced dehydration during a subsequent 90-min exercise bout. It was hypothesized that cardiovascular, thermoregulatory, and hormonal variables would be the same between intravenous and oral rehydration because of similar restoration of plasma volume (PV) and osmolality (Osmo). Eight non-heat-acclimated men received three experimental treatments (counterbalanced design) immediately after exercise-induced dehydration (33°C) to −4% body weight loss. Treatments were intravenous 0.45% NaCl (iv; 25 ml/kg), no fluid (NF), and oral saline (Oral; 25 ml/kg). After rehydration and rest (2 h total), subjects walked at 50% maximal O2 consumption for up to 90 min at 36°C. The following observations were made: 1) heart rate was higher ( P < 0.05) in Oral vs. iv at minutes 45, 60, and 75 of exercise; 2) rectal temperature, sweat rate, percent change in PV, and change in plasma Osmo were similar between iv and Oral; 3) change in plasma norepinephrine decreased less ( P < 0.05) in Oral compared with iv at minute 45; 4) changes in plasma adrenocorticotropic hormone and cortisol were similar between iv and Oral after exercise was initiated; and 5) exercise time was similar between iv (77.4 ± 5.4 min) and Oral (84.2 ± 2.3 min). These data suggest that after exercise-induced dehydration, iv and Oral were equally effective as rehydration treatments. Thermoregulation, change in adrenocorticotropic hormone, and change in cortisol were not different between iv and Oral after exercise began; this is likely due to similar percent change in PV and change in Osmo. </jats:p
The effects of ten weeks of resistance and combined plyometric/sprint training with the Meridian Elyte athletic shoe on muscular performance in women
No full textRatamess, N.A., W.J. Kraemer, J.S. Volek, D.N. French, M.R. Rubin, A.L. Gómez, R.U. Newton, and C.M. Maresh. The effects of ten weeks of resistance and combined plyometric/ sprint training with the Meridian Elyte athletic shoe on muscular performance in women. J. Strength Cond. Res. 21(3):882-887. 2007. - The purpose of this investigation was to examine the combined effects of resistance and sprint/plyometric training with or without the Meridian Elyte athletic shoe on muscular performance in women. Fourteen resistance-trained women were randomly assigned to one of 2 training groups: (a) an athletic shoe (N = 6) (AS) group or (b) the Meridian Elyte (N = 8) (MS) group. Training was performed for 10 weeks and consisted of resistance training for 2 days per week and 2 days per week of sprint/plyometric training. Linear periodized resistance training consisted of 5 exercises per workout (4 lower body, 1 upper body) for 3 sets of 3-12 repetition maximum (RM). Sprint/plyometric training consisted of 5-7 exercises per workout (4-5 plyometric exercises, 40-yd and 60-yd sprints) for 3-6 sets with gradually increasing volume (8 weeks) followed by a 2-week taper phase. Assessments for 1RM squat and bench press, vertical jump, broad jump, sprint speed, and body composition were performed before and following the 10-week training period. Significant increases were observed in both AS and MS groups in IRM squat (12.0 vs. 14.6 kg), bench press (6.8 vs. 7.4 kg), vertical jump height (3.3 vs. 2.3 cm), and broad jump (17.8 vs. 15.2 cm). Similar decreases in peak 20-, 40-, and 60-m sprint times were observed in both groups (20 m: 0.14 vs. 0.11 seconds; 40 m: 0.29 vs. 0.34 seconds; 60 m: 0.45 vs. 0.46 seconds in AS and MS groups, respectively). However, when sprint endurance (the difference between the fastest and slowest sprint trials) was analyzed, there was a significantly greater improvement at 60 m in the MS group. These results indicated that similar improvements in peak sprint speed and jumping ability were observed following 10 weeks of training with either shoe. However, high-intensity sprint endurance at 60 m increased to a greater extent during training with the Meridian Elyte athletic shoe
Nutrition and Hydration Issues for Combat Sport Athletes
No full textTo optimize performance improvements and to enhance skeletal muscle recovery from high-intensity training, the athlete needs to ensure adequate energy and protein consumption. Protein intake may have even greater relevance during periods of weight loss often associated with the combat sport athlete. Combat sport athletes often use water restriction to accomplish desired weight loss. This has several important performance and physiological implications that pose significant health risks. This paper will focus on several nutritional and hydration strategies and how they specifically relate to combat sports with regard to training and competition. © National Strength and Conditioning Association
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The role and policy implications of selected external factors as applied to the developmental patterns of five Wyoming fuels
No full textThe developmental patterns of five fuel resources located within
the state of Wyoming are examined through time and in relation to
several factors external to the location of the fuels. An historic
description and inventory of the five fuels: petroleum; natural gas;
oil shale; coal; uranium are presented. External factors including
governmental activities; economic and technological conditions as
well as socio-environmental factors are portrayed as having cyclical
Impacts upon the developmental and utilization patterns of Wyoming's
fuels. Emphasis is particularly placed upon the ever increasing
impact of societal concerns regarding environmental aspects of
governmental and economic/technological activities. The external
factors are examined in terms of their total impact on Wyoming's role
as a regional and national supplier of fuel.
Spatial aspects of the fuel resources in terms of their
acquisition, transportation facilities and market areas are examined
through time using various descriptive and quantitative measures.
Policy implications for the successful implementation of federal
energy development programs are discussed and evaluated in relation
to an investigation of the aforementioned external factors, spatial
considerations, and constraints. The author posits that the implica:-
tions for policy decisions concerning energy on a national level are
magnified at either a regional or state level. The solutions to
environmental, economic and social problems as well as the traditional
technological difficulties of mining which are found in Wyoming may
be a microcosm of solutions which could be implemented on a national
scale.
Wyoming has traditionally been an exporter of its fuel resources,
and the state's economy has generally been reactive to the national
and political environment. The state has now begun to assume a role
of leadership in energy resource development. Assuming an ever
greater role as a regional and national supplier of fuels, Wyoming's
future role may become more prominent in national energy affairs
Role of nurses in managing menstrual health using mobile tracking
No full textMobile technologies provide a unique opportunity to improve menstrual health awareness, management, and care. Nurses should consider incorporating a mobile tracking component into patient-care settings to promote menstrual health awareness and advocacy and to help create individualized healthcare plans
Alterations in Arginine Vasopressin with Exercise, Environmental Stress and Other Modifying Factors
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