Article

Water balance, hydration status, and fat-free mass hydration in younger and older adults.

Department of Foods and Nutrition, Purdue University, West Lafayette, IN 47907, USA.
American Journal of Clinical Nutrition (Impact Factor: 6.92). 07/2005; 81(6):1342-50.
Source: PubMed

ABSTRACT Older adults are at increased risk of dehydration, yet water balance is understudied in this population.
This controlled diet study assessed the effect of age on water input, output, and balance in healthy adults. Hydration status (plasma osmolality and urine specific gravity) and body composition were also measured.
Eleven men and 14 women aged 23-46 y and 10 men and 11 women aged 63-81 y were subjects. Water balance was assessed during days 7-10 of three 18-d controlled feeding trials with protein intakes of 0.50, 0.75, and 1.00 g . kg(-1) . d(-1). Total water input included water from the provided foods and beverages, ad libitum intake, and metabolic production. Water output included the losses in urine and stool and the insensible losses from respiration and nonsweating perspiration.
Ad libitum water consumption, total water intake, water output through urine, total water output, and net water balance were not different in the older subjects than in the younger subjects. Markers of hydration status were within the range of clinical normalcy for all groups. Total body water (TBW) was not significantly different, fat-free mass (FFM) was significantly lower (P < 0.05), and FFM hydration (TBW:FFM) was significantly higher (P < 0.05) in the older subjects than in the younger subjects. Dietary protein intake did not influence any of these results.
These results show that healthy older adults maintain water input, output, and balance comparable to those of younger adults and have no apparent changes in hydration status. The results support that the hydration of FFM is increased in older men and women.

0 Bookmarks
 · 
106 Views
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: In developing countries where access to water and food is not guaranteed, women may have to travel long distances or engage in intense physical activities to gather food. This may compromise their water requirements and overall nutritional status. The aim of the study was to determine water turnover, physical activity and body composition among women in Kenya and to describe the differences between rural and urban Kenyan women. Thirty women from Narok County who were not pregnant at the time of the study were recruited. Body mass index (BMI) was calculated by dividing weight in kilograms by height in meters squared. Deuterium dilution was used to determine total body water (TBW) and water turnover was measured from deuterium elimination. Fat-free mass (FFM) was calculated by assuming a constant hydration fraction of 73.2%. Accelerometers (Actigraph GT3X) were used to assess physical activity and expressed as Vector magnitude counts per day (VM/day). Simple and multiple linear regressions were used to define the determinants of water turnover. Mean BMI was 23.4 ± 4.1 and 21.5 ± 3.8 among rural and urban women respectively. The prevalence of overweight (BMI > 25 kg/m2) was 24.1% and of underweight (BMI < 18.4 kg/m2) was 25%. The mean total body water (TBW) was 29.3 ± 4.2 liters (L) and water turnover was 3.2 ± 0.8 liters per day (L/day). Water loss was positively associated with BMI (R2 = .45, p < 0.001, n = 28) and Fat mass index (FMI) (R2 = .41, p < 0.001, n = 28). Water loss was also positively associated with physical activity (PA) (R2 = .25, p < 0.05, n = 22). Multiple regression analysis showed that physical activity in addition to BMI in the model explained an additional 15% of the variation in water turnover (r2 = 0.53, p < 0.05; ∆r2 = 0.15, p < 0.05, n = 22) compared to BMI alone (r2 = 0.38, p < 0.005 n = 22). BMI together with physical activity were the strongest predictors of water loss.
    BMC Public Health 01/2014; 14(1):1212. DOI:10.1186/1471-2458-14-1212 · 2.32 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Purpose This study tested the hypothesis that hypoxia exacerbates reductions in body mass observed during unloading. Methods To discern the separate and combined effects of simulated microgravity and hypoxia, 11 healthy males underwent three 21-day campaigns in a counterbalanced fashion: (1) normoxic bed rest (NBR; FiO2 = 0.209; PiO2 = 133.1 ± 0.3); (2) hypoxic ambulatory confinement (HAMB; FiO2 = 0.141 ± 0.004; PiO2 = 90.0 ± 0.4; ~4,000 m); and (3) hypoxic bed rest (HBR; FiO2 = 0.141 ± 0.004; PiO2 = 90.0 ± 0.4). The same dietary menu was applied in all campaigns. Targeted energy intakes were estimated individually using the Harris–Benedict equation taking into account whether the subjects were bedridden or ambulatory. Body mass and water balance were assessed throughout the campaigns. Whole body and regional body composition was determined before and after the campaigns using dual-energy X-ray absorptiometry. Before and during the campaigns, indirect calorimetry and visual analogue scores were employed to assess the resting energy expenditure (REE) and perceived appetite sensations, respectively. Results Energy intakes were lower than targeted in all campaigns (NBR: −5 %; HAMB: −14 %; HBR: −6 %; P < 0.01). Body mass significantly decreased following all campaigns (NBR: −3 %; HAMB: −4 %; HBR: −5 %; P < 0.01). While fat mass was not significantly altered, the whole body fat free mass was reduced (NBR: −4 %; HAMB: −5 %; HBR: −5 %; P < 0.01), secondary to lower limb fat-free mass reduction. Water balance was comparable between the campaigns. No changes were observed in REE and perceived appetite. Conclusions Exposure to simulated altitude of ~4,000 m does not seem to worsen the whole body mass and fat-free mass reductions or alter resting energy expenditure and appetite during a 21-day simulated microgravity.
    Arbeitsphysiologie 08/2014; DOI:10.1007/s00421-014-2963-1 · 2.30 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Objectives. To examine the current state of the science regarding the role of systemic hydration in vocal function and health. Study Design. Literature review. Methods. Literature search spanning multiple disciplines, including speech-language pathology, nutrition and dietetics, medicine, sports and exercise science, physiology, and biomechanics. Results. The relationship between hydration and physical function is an area of common interest among multiple professions. Each discipline provides valuable insight into the connection between performance and water balance, as well as complimentary methods of investigation. Existing voice literature suggests a relationship between hydration and voice production; however, the underlying mechanisms are not yet defined and a treatment effect for systemic hydration remains to be demonstrated. Literature from other disciplines sheds light on methodological shortcomings and, in some cases, offers an alternative explanation for observed phenomena. Conclusions. A growing body of literature in the field of voice science is documenting a relationship between hydration and vocal function; however, greater understanding is required to guide best practice in the maintenance of vocal health and management of voice disorders. Integration of knowledge and technical expertise from multiple disciplines facilitates analysis of existing literature and provides guidance as to future research.
    Journal of voice: official journal of the Voice Foundation 05/2014; 28(5). DOI:10.1016/j.jvoice.2014.01.007 · 0.95 Impact Factor

Preview

Download
2 Downloads
Available from