Javier S. Morales

Effects of Exercise on the Immune Function of Pediatric Patients With Solid Tumors: Insights From the PAPEC Randomized Trial

Abstract The purpose of this study was to assess the effects of an in-hospital exercise intervention during neoadjuvant chemotherapy on the inflammatory profile and immune cell subpopulation in 20 children with solid tumors (control [n = 11] and exercise group [n = 9]). Although no significant interaction (group × time) effect was found with an analysis of variance test, we found a trend toward an interaction effect for natural killer cells expressing the immunoglobulin-like receptor KIR2DS4, with their numbers remaining stable in the exercise group but increasing in controls. Our data support that exercise interventions are safe in pediatric cancer patients with solid tumors during chemotherapy treatment despite its aggressive, immunosuppressive nature.

Comment on: “Drinking Strategies: Planned Drinking versus Drinking to Thirst”

We have read with interest the topical review article [1] entitled ‘‘Drinking strategies: planned drinking versus drinking to thirst’’, where Dr. Kenefick summarizes the evidence on pre-established drinking plans versus ad libitum drinking during exercise with a main focus on performance. Assessing an individual’s hydration pattern during exercise has received special attention in the sports science field based on the notion that dehydration dysregulates fluid homeostasis, thereby leading to physiological stress and impaired performance [2]. Kenefick [1] establishes a 2% body weight (BW) loss during exercise as a threshold for impairment of thermoregulatory and cardiovascular function, with subsequent decreases in exercise performance. His final advice is to avoid drinking to thirst in order to prevent BW losses[ 2% during activities of high intensity or long duration ([ 1–2 h), or when exercising in warm/hot environments. However, some aspects of the relationship between dehydration (understood as a BW loss[ 2%) and physiological stress or performance must be discussed. More importantly, certain health concerns should not be overlooked in the first instance. Although Kenefick [1] does highlight the importance of not consuming too much fluid (i.e. avoiding gaining BW after exertion), we believe more serious attention must be given to the potential risks of overdrinking [3]. The author describes cases of exercise-induced hyponatremia (EAH; defined as a plasma sodium level\ 135 mmol/L) as ‘rare’, when in fact a worrying prevalence of EAH has been reported in endurance events [4], notably 13% of Boston Marathon participants [5] and 11% of participants in the Ironman European Championship [6]. Importantly, the fact that EAH cases are usually asymptomatic or mildly symptomatic (e.g. nausea) does not rule out the possibility that this condition can lead to severe clinical manifestations, or even a fatal outcome [4]. By contrast, there is little evidence to support a cause–effect relationship between dehydration per se (in the absence of thirst) and onset of major health problems such as exertional muscle cramps, heat illnesses (including heat stroke), or cognitive impairment [2]. Therefore, special caution should be exercised when drinking beyond thirst. Furthermore, Dr. Kenefick’s specific recommendation to drink beyond thirst for exercise durations above 1–2 h is in disagreement with the finding that longer race times have been associated with a higher risk of developing EAH [5]. In fact, BW gain is not a good marker of EAH risk when drinking ad libitum; although this condition is commonly associated with an increased BW, it can also occur without associated gains in BW [7]. Health issues aside, some discussion is also needed on the performance effects of dehydration rates above the advocated 2% threshold. Dr. Kenefick [1] proposes a link & Pedro L. Valenzuela pedrol.valenzuela@edu.uah.es

Physical strategies to prevent disuse-induced functional decline in the elderly

Disuse situations can have serious adverse health consequences in the elderly, including mainly functional impairment with subsequent increase in the risk of falls or morbimortality. The present review provides clinicians and care givers with detailed and practical information on the feasibility and effectiveness of physical strategies that are currently available to prevent or attenuate the functional decline that occurs secondarily to disuse situations in the elderly, notably in the hospital setting. In this context, active approaches such as resistance exercises and maximal voluntary contractions, which can be performed both isometrically and dynamically, are feasible during most immobilization situations including in hospitalized old people and represent powerful tools for the prevention of muscle atrophy. Aerobic exercise should also be prescribed whenever possible to reduce the loss of cardiovascular capacity associated with disuse periods. Other feasible strategies for patients who are unwilling or unable to perform volitional exercise comprise neuromuscular electrical stimulation, vibration, and blood flow restriction. However, they should ideally be applied synchronously with voluntary exercise to obtain synergistic benefits.

Intradialytic Exercise: One Size Doesn’t Fit All

Purpose: Hemodialysis patients commonly have impaired physical performance and mental health. We studied the effects of an intradialytic exercise program on these variables. Methods: 27 patients (33% women; 68 ± 13 years) were enrolled in a 14-week intradialytic endurance-resistance training program (‘exercise’ group, 40 programmed sessions per patient); 40 hemodialysis patients (28% women; 68 ± 11 years) performing no exercise during the same time length were used as controls. Endpoints included physical performance (6-min walk test [6MWT], 10-repetition sit to stand [STS-10] and handgrip strength), emotional status (Beck’s depression inventory and State-Trait Anxiety Inventory), and mental and physical component scores of the short-from (SF)-12 Health Survey. Results: There were no differences (p> 0.05) between groups at baseline for sex distribution, or mean age, body mass index and time spent on dialysis. Exercise benefits were observed for 6MWT (11 and −3% for the exercise and control groups, respectively; p < 0.001), STS-10 performance time (-22 and 6%; p < 0.001) and handgrip strength (4 and −4%; p < 0.02). No significant benefits (p> 0.05) were observed for emotional status endpoints or SF-12 component scores. Despite significant benefits on physical performance, the proportion of clinically meaningful responders was low (<50%). Responsiveness was dependent on baseline physical performance (p < 0.05) but not on age or sex (p > 0.05). Conclusion: A 14-week intradialytic training program induced significant improvements on physical performance. However, the rate of clinically meaningful responders observed in the present study was low, being the level of responsiveness dependent on baseline physical status. Efforts to individualize exercise prescription are needed in clinical practice.

Vitamin D for Healthy Aging

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