SUMMARYACSM Position Stand on The Recommended Quantity and Quality of Exercise for Developing and Maintaining Cardiorespiratory and Muscular Fitness, and Flexibility in Adults. Med. Sci. Sports Exerc., Vol. 30, No. 6, pp. 975-991, 1998. The combination of frequency, intensity, and duration of chr

http://myweb.facstaff.wwu.edu/chalmers/pdfs/acsm position stand - quantity and quality of exercise.pdf

ACSM Position Stand: The Recommended Quantity and Quality of Exercise for Developing and Maintaining Cardiorespiratory and Muscular Fitness, and Flexibility in Healthy Adults

It is the position of the American College of Sports Medicine that adequate fluid replacement helps maintain hydration and, therefore, promotes the health, safety, and optimal physical performance of individuals participating in regular physical activity. This position statement is based on a comprehensive review and interpretation of scientific literature concerning the influence of fluid replacement on exercise performance and the risk of thermal injury associated with dehydration and hyperthermia. Based on available evidence, the American College of Sports Medicine makes the following general recommendations on the amount and composition of fluid that should be ingested in preparation for, during, and after exercise or athletic competition: 1) It is recommended that individuals consume a nutritionally balanced diet and drink adequate fluids during the 24-hr period before an event, especially during the period that includes the meal prior to exercise, to promote proper hydration before exercise or competition. 2) It is recommended that individuals drink about 500 ml (about 17 ounces) of fluid about 2 h before exercise to promote adequate hydration and allow time for excretion of excess ingested water. 3) During exercise, athletes should start drinking early and at regular intervals in an attempt to consume fluids at a rate sufficient to replace all the water lost through sweating (i.e., body weight loss), or consume the maximal amount that can be tolerated. 4) It is recommended that ingested fluids be cooler than ambient temperature [between 15 degrees and 22 degrees C (59 degrees and 72 degrees F])] and flavored to enhance palatability and promote fluid replacement. Fluids should be readily available and served in containers that allow adequate volumes to be ingested with ease and with minimal interruption of exercise. 5) Addition of proper amounts of carbohydrates and/or electrolytes to a fluid replacement solution is recommended for exercise events of duration greater than 1 h since it does not significantly impair water delivery to the body and may enhance performance. During exercise lasting less than 1 h, there is little evidence of physiological or physical performance differences between consuming a carbohydrate-electrolyte drink and plain water. 6) During intense exercise lasting longer than 1 h, it is recommended that carbohydrates be ingested at a rate of 30-60 g.h(-1) to maintain oxidation of carbohydrates and delay fatigue. This rate of carbohydrate intake can be achieved without compromising fluid delivery by drinking 600-1200 ml.h(-1) of solutions containing 4%-8% carbohydrates (g.100 ml(-1)). The carbohydrates can be sugars (glucose or sucrose) or starch (e.g., maltodextrin). 7) Inclusion of sodium (0.5-0.7 g.1(-1) of water) in the rehydration solution ingested during exercise lasting longer than 1 h is recommended since it may be advantageous in enhancing palatability, promoting fluid retention, and possibly preventing hyponatremia in certain individuals who drink excessive quantities of fluid. There is little physiological basis for the presence of sodium in n oral rehydration solution for enhancing intestinal water absorption as long as sodium is sufficiently available from the previous meal.

American College of Sports Medicine position stand. Exercise and fluid replacement

Preface Abstract 1. Basis of ICRP Reference Values 2. Summary of Reference Values 3. Embryo and Fetus 4. Total Body 5. Respiratory System 6. Alimentary System 7. Circulatory and Lymphatic Systems 8. Urogenital System 9. Skeletal System 10. Integumentary System 11. Additional Organs and Tissues 12. Pregnant Woman: Anatomical and Physiological Changes 13. Elemental Composition of the Body Reference

Basic anatomical and physiological data for use in radiological protection : reference values

This report presents detailed information on age- and gender-related differences in the anatomical and physiological characteristics of reference individuals. These reference values provide needed input to prospective dosimetry calculations for radiation protection purposes for both workers and members of the general public. The purpose of this report is to consolidate and unify in one publication, important new information on reference anatomical and physiological values that has become available since Publication 23 was published by the ICRP in 1975. There are two aspects of this work. The first is to revise and extend the information in Publication 23 as appropriate. The second is to provide additional information on individual variation among grossly normal individuals resulting from differences in age, gender, race, or other factors. This publication collects, unifies, and expands the updated ICRP reference values for the purpose of providing a comprehensive and consistent set of age- and gender-specific reference values for anatomical and physiological features of the human body pertinent to radiation dosimetry. The reference values given in this report are based on: (a) anatomical and physiological information not published before by the ICRP; (b) recent ICRP publications containing reference value information; and (c) information in Publication 23 that is still considered valid and appropriate for radiation protection purposes. Moving from the past emphasis on ‘Reference Man’, the new report presents a series of reference values for both male and female subjects of six different ages: newborn, 1 year, 5 years, 10 years, 15 years, and adult. In selecting reference values, the Commission has used data on Western Europeans and North Americans because these populations have been well studied with respect to antomy, body composition, and physiology. When appropriate, comparisons are made between the chosen reference values and data from several Asian populations. The first section of the report provides summary tables of all the anatomical and physiological parameters given as reference values in this publication. These results give a comprehensive view of reference values for an individual as influenced by age and gender. The second section describes characteristics of dosimetric importance for the embryo and fetus. Information is provided on the development of the total body and the timing of appearance and development of the various organ systems. Reference values are provided on the mass of the total body and selected organs and tissues, as well as a number of physiological parameters. The third section deals with reference values of important anatomical and physiological characteristics of reference individuals from birth to adulthood. This section begins with details on the growth and composition of the total body in males and females. It then describes and quantifies anatomical and physiological characteristics of various organ systems and changes in these characteristics during growth, maturity, and pregnancy. Reference values are specified for characteristics of dosimetric importance. The final section gives a brief summary of the elemental composition of individuals. Focusing on the elements of dosimetric importance, information is presented on the body content of 13 elements: calcium, carbon, chloride, hydrogen, iodine, iron, magnesium, nitrogen, oxygen, potassium, sodium, sulphur, and phosphorus.

https://journals.sagepub.com/doi/pdf/10.1016/S0146-6453%2803%2900002-2

Basic anatomical and physiological data for use in radiological protection: reference values ICRP Publication 89: Approved by the Commission in September 2001

Thank you for downloading textbook of work physiology physiological bases of exercise. As you may know, people have look hundreds times for their chosen novels like this textbook of work physiology physiological bases of exercise, but end up in infectious downloads. Rather than reading a good book with a cup of tea in the afternoon, instead they cope with some harmful virus inside their desktop computer.

Textbook Of Work Physiology Physiological Bases Of Exercise

The interaction between the volume and composition of fluids ingested was investigated in terms of rehydration effectiveness. Twelve male volunteers, dehydrated by 2.06 +/- 0.02% (mean +/- SE) of body mass by intermittent cycle exercise, consumed a different drink volume on four separate weeks; six subjects received drink L (23 mmol.l-1 Na+) in each trial and six were given drink H (61 mmol.l-1 Na+). Volumes consumed were equivalent to 50%, 100%, 150%, and 200% of body mass loss (trials A, B, C, and D, respectively). Blood and urine samples were obtained before exercise and for 7.5 h after exercise. Less urine was excreted following rehydration in trial A than in all other trials. Cumulative urine output (median ml) was less in trial B (493, range 181-731) than D (1361, range 1014-1984), which was not different from trial C (867, range 263-1191) in group L. In group H, the volume excreted in trial B (260, range 137-376) was less than trials C (602, range 350-994) and D (1001, range 714-1425), and the volume in trial C was less than in trial D. These results suggest that both sodium concentration and fluid volume consumed interact to affect the rehydration process. A drink volume greater than sweat loss during exercise must be ingested to restore fluid balance, but unless the sodium content of the beverage is sufficiently high this will merely result in an increased urinary output.

Post-exercise rehydration in man: effects of volume consumed and drink sodium content.

During the 9th month (Ramadan) of the Islamic calendar (Hijra) many millions of adult Muslims all over the world fast during the daylight hours. Since Hijra is a lunar calendar, Ramadan occurs at different times in the seasonal year over a 33-year cycle. Fasting during Ramadan is partial because the abstention from food, fluid, tobacco and caffeine is from sunrise to sunset. Several categories of people are exempt or can postpone the Ramadan fast. The effect on health and well being of the month-long intermittent fast and fluid restriction has been studied in various potentially vulnerable groups in addition to normal healthy individuals in many countries. The majority of the studies have found significant metabolic changes, but few health problems arising from the fast. A reduction in drug compliance was an inherent negative aspect of the fast. Common findings of the studies reviewed were increased irritability and incidences of headaches with sleep deprivation and lassitude prevalent. A small body mass loss is a frequent, but not universal, outcome of Ramadan. During the daylight hours of Ramadan fasting, practising Muslims are undoubtedly dehydrating, but it is not clear whether they are chronically hypohydrated during the month of Ramadan. No detrimental effects on health have as yet been directly attributed to negative water balance at the levels that may be produced during Ramadan.

Effects on health of fluid restriction during fasting in Ramadan

Hydration status is not easily measured, but acute changes in hydration status are often estimated from body mass change. Changes in body mass are also often used as a proxy measure for sweat losses. There are, however, several sources of error that may give rise to misleading results, and our aim in this paper is to quantify these potential errors. Respiratory water losses can be substantial during hard work in dry environments. Mass loss also results from substrate oxidation, but this generates water of oxidation which is added to the body water pool, thus dissociating changes in body mass and hydration status: fat oxidation actually results in a net gain in body mass as the mass of carbon dioxide generated is less than the mass of oxygen consumed. Water stored with muscle glycogen is presumed to be made available as endogenous carbohydrate stores are oxidized. Fluid ingestion and sweat loss complicate the picture by altering body water distribution. Loss of hypotonic sweat results in increased osmolality of body fluids. Urine and faecal losses can be measured easily, but changes in the water content of the bladder and the gastrointestinal tract cannot. Body mass change is not always a reliable measure of changes in hydration status and substantial loss of mass may occur without an effective net negative fluid balance.

https://www.tandfonline.com/doi/pdf/10.1080/02640410600875143

Errors in the estimation of hydration status from changes in body mass.

This study investigated the effects of post-exercise rehydration with fluid alone or with a meal plus fluid. Eight healthy volunteers (five men, three women) were dehydrated by a mean of 2.1 (SEM 0.0)% of body mass by intermittent cycle exercise in a warm [34 (SEM 0)°C], humid [55 (SEM 1)% relative humidity] environment. Over 60 min beginning 30 min after exercise, the subjects ingested a commercially-available sports drink (21 mmol · l−1 Na+, 3.4 mmol · l− K+, 12 mmol · l−1 Cl−1) on trials A and B; on trial C a standard meal [63 kJ · kg−1 body mass (53% CHO, 28%fat,19%protein; 0.118 mmol · kJ−1 Na+, 0.061 mmol · kJ−1 K+)] plus drink (1 mmol · l−1 Na+, 0.4 mmol · l−1 K+, 1 mmol · l−1 Cl−) were consumed. Water intake (in millilitres) was 150% of the mass loss (in grams). The trials took place after an overnight fast and were separated by 7 days. Blood and urine samples were collected at intervals throughout the study. Blood was analysed for haematocrit, haemoglobin concentration, serum osmolality, Na+, Ku+ and Cl− concentrations and plasma angiotensin II concentration. Urine volume, osmolality and electrolyte concentrations were measured. Dehydration resulted in a mean 5.2 (SEM 1.3)% reduction in plasma volume. With the exception of serum osmolality, which was higher on trial B than A at the end of the rehydration period, no differences were recorded for any of the measured parameters between trials A and B. Cumulative urine output following rehydration was lower (P < 0.01) on trial C [median 665 (range 396–1190) ml] than on trial B [median 934 (range 550–1403) ml] which was not different (P = 0.44) from trial A [median 954 (range 474–1501) ml]. Less urine was produced over the 1-h period ending 2 h after rehydration on trial C than on B (P = 0.01). On trials A and B the subjects were in net negative fluid balance by 337 (range 779-minus 306) ml and 373 (range 680-minus 173) ml, respectively (P < 0.01): on trial C the subjects were no different from their initial euhydrated state [median minus 29 (range minus 421−137) ml] 6 h after the end of rehydration (P = 1.00). A larger fraction of total water intake was retained when the standard meal plus drink was consumed. This may have been due to the larger quantities of Na+ and K+ ingested with the meal [mean 63 (SEM 4)mmol Na+, 21.3 (SEM 1.3)mmol K+] than with the drink [mean 42 (SEM 2) mmol Na+, 6.8 (SEM 0.4) mmol K+]. There was no difference between trials B and C in any of the measured blood parameters, but urinary Na+ and K+ excretion were both higher on trial C than B. These results suggest that post-exercise fluid replacement can be achieved by ingestion of water if consumed in sufficient volume together with a meal providing significant amounts of electrolytes.

Restoration of fluid balance after exercise-induced dehydration: effects of food and fluid intake

This study examined the effects on water balance of adding electrolytes to fluids ingested after exercise-induced dehydration. Eight healthy male volunteers were dehydrated by approximately 2% of body mass by intermittent cycle exercise. Over a 30-min period after exercise, subjects ingested one of the four test drinks of a volume equivalent to their body mass loss. Drink A was a 90 mmol·l−1 glucose solution; drink B contained 60 mmol·l−1 sodium chloride; drink C contained 25 mmol·l−1 potassium chloride; drink D contained 90 mmol·l−1 glucose, 60 mmol·l−1 sodium chloride and 25 mmol·l−1 potassium chloride. Treatment order was randomised. Blood and urine samples were obtained at intervals throughout the study; subjects remained fasted throughout. Plasma volume increased to the same extent after the rehydration period on all treatments. Serum electrolyte (Na+, K+ and Cl−) concentrations fell initially after rehydration before returning to their pre-exercise levels. Cumulative urine output was greater after ingestion of drink A than after ingestion of any of the other drinks. On the morning following the trial, subjects were in greater net negative fluid balance [mean (SEM);P<0.02] on trial A [745 (130) ml] than on trials B [405 (51) ml], C [467 (87) ml] or D [407 (34) ml]. There were no differences at any time between the three electrolyte-containing solutions in urine output or net fluid balance. One hour after the end of the rehydration period, urine osmolality had fallen, with a significant treatment effect (P=0.016); urine osmolality was lowest after ingestion of drink A. On the morning after the test, subjects were in greater net negative sodium balance (P<0.001) after trials A and C than after trials B and D. Negative potassium balance was greater (P<0.001) after trials A and B than after C and D. Chloride balance was positive after drink D and a smaller negative balance (P<0.001) was observed after drink B than after A and C. These results suggest that although the measured blood parameters were similar for all trials, better whole body water and electrolyte balance resulted from the ingestion of electrolyte-containing drinks. There appeared, however, to be no additive effect of including both sodium and potassium under the conditions of this experiment.

John B. Leiper

Papers

Post-exercise rehydration in man: effects of volume consumed and drink sodium content.

Effects on health of fluid restriction during fasting in Ramadan

Errors in the estimation of hydration status from changes in body mass.

Restoration of fluid balance after exercise-induced dehydration: effects of food and fluid intake

Post-exercise rehydration in man: effects of electrolyte addition to ingested fluids.