1.
The effect of alternate-day caloric restriction on the metabolic consequences of 8 days of bed rest in healthy lean men: a randomized trial.
Harder-Lauridsen, NM, Nielsen, ST, Mann, SP, Lyngbæk, MP, Benatti, FB, Langkilde, AR, Law, I, Wedell-Neergaard, AS, Thomsen, C, Møller, K, et al
Journal of applied physiology (Bethesda, Md. : 1985). 2017;(2):230-241
Abstract
UNLABELLED Physical activity and alternate-day fasting/caloric restriction may both ameliorate aspects of the metabolic syndrome, such as insulin resistance, visceral fat mass accumulation, and cognitive impairment by overlapping mechanisms. The purpose of this study was to test the hypothesis that alternate-day caloric restriction (ADCR) with overall energy balance would reduce insulin resistance and accumulation of visceral fat, in addition to improving cognitive functions, after 8 consecutive days in bed. Healthy, lean men (n = 20) were randomized to 1) 8 days of bed rest with three daily isoenergetic meals (control group, n = 10); and 2) 8 days of bed rest with 25% of total energy requirements every other day and 175% of total energy requirements every other day (ADCR group). Oral glucose tolerance testing, dual-energy X-ray absorptiometry (DXA) scans, magnetic resonance imaging of the abdomen and brain, V̇o2max, and tests for cognitive function were performed before and after bed rest. In addition, daily fasting blood samples and 24-h glucose profiles by continuous glucose monitoring system were assessed during the 8 days of bed rest period. Bed rest induced insulin resistance, visceral fat accumulation, and worsening of mood. No positive effects emerged from ADCR on these negative health outcomes. Compared with the control group, ADCR was associated with improved and steadier glycemic control on fasting days and higher glycemic fluctuation and indexes of insulin resistance on overeating days. In contrast to our hypothesis, the metabolic impairment induced by 8 days of bed rest was not counteracted by ADCR with overall energy balance. NEW & NOTEWORTHY Alternate-day caloric restriction without overall energy reduction does not ameliorate the metabolic impairment induced in lean men by 8 days of bed rest.
2.
Bedrest and sarcopenia.
Coker, RH, Wolfe, RR
Current opinion in clinical nutrition and metabolic care. 2012;(1):7-11
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Abstract
PURPOSE OF REVIEW The primary focus of this review is to characterize the physiological elements of sarcopenia. In addition, we will also describe the impact of bedrest on sarcopenia and how various countermeasures may be able to offset the deleterious clinical consequences of unanticipated bedrest or hospitalization. It is well known that the aging process presents many challenges to the maintenance of overall health. With the increasing rate of obesity and the potentially simultaneous development of sarcopenia, bedrest presents a difficult clinical challenge to the elderly individual. RECENT FINDINGS The etiology of accelerated sarcopenia has been described as a syndrome. The characteristics of this syndrome include combined alterations in neuromuscular control and muscle protein synthesis that increase the risk of morbidity and mortality in the elderly population. Moreover, the acute onset of bedrest-induced insulin resistance may further complicate the nutritionally derived maintenance of muscle mass and physical function. SUMMARY Even though many questions remain unresolved concerning the optimal clinical management of elderly individuals who undergo unanticipated bedrest, the supplementation of essential amino acids has shown promise as a therapeutic strategy to minimize the detrimental influence of hospitalization in the elderly. In turn, this nutritional adjunctive therapy may reduce the length of stay and the likelihood of repeated hospitalization.