Impact of exercise interventions on physical fitness in breast cancer patients and survivors: a systematic review.

BACKGROUND: This systematic review aims to identify the effects of exercise interventions in patients with breast cancer (BCP) and survivors (BCS) on selected variables of physical fitness. METHODS: A comprehensive literature search was conducted using Medline and Scopus. Randomized controlled trials with isolated exercise interventions in BCP and BCS women (< 5 years from therapy completion) were included. The risk of bias (RoB) assessment was conducted using the Cochrane RoB-2-tool. Variables regarding cardiorespiratory fitness (CRF), strength (ST), fatigue (F) and health-related quality of life (HRQoL) were discussed. RESULTS: Of the 336 studies initially identified, 22 met all the inclusion criteria and were deemed eligible. RoB assessment indicated that the studies had predominantly "some concerns" or had "low RoB", with only 3 studies presenting a "high RoB". The mean duration and frequency of exercise interventions were 19 weeks and 3 sessions/week, performed at moderate intensity (65% VO2max and 66% 1RM, for aerobic and resistance-training interventions, respectively). CONCLUSIONS: Exercise interventions seem to be a valuable strategy in BCP to avoid the decline of CRF, ST, F and HRQoL. Conversely, improved physical function among BCS is observed for the same variables. Resistance training and combined interventions seem to provide the most encouraging variations of the selected outcomes. PROSPERO REGISTRATION ID: CRD42021237917.

Tissue losses and metabolic adaptations both contribute to the reduction in resting metabolic rate following weight loss.

OBJECTIVE: To characterize the contributions of the loss of energy-expending tissues and metabolic adaptations to the reduction in resting metabolic rate (RMR) following weight loss. METHODS: A secondary analysis was conducted on data from the Comprehensive Assessment of Long-term Effects of Reducing Intake of Energy study. Changes in RMR, body composition, and metabolic hormones were examined over 12 months of calorie restriction in 109 individuals. The contribution of tissue losses to the decline in RMR was determined by weighing changes in the size of energy-expending tissues and organs (skeletal muscle, adipose tissue, bone, brain, inner organs, residual mass) assessed by dual-energy X-ray absorptiometry with their tissue-specific metabolic rates. Metabolic adaptations were quantified as the remaining reduction in RMR. RESULTS: RMR was reduced by 101 ± 12 kcal/d as participants lost 7.3 ± 0.2 kg (both p < 0.001). On average, 60% of the total reduction in RMR were explained by energy-expending tissues losses, while 40% were attributed to metabolic adaptations. The loss of skeletal muscle mass (1.0 ± 0.7 kg) was not significantly related to RMR changes (r = 0.14, p = 0.16), whereas adipose tissue losses (7.2 ± 3.0 kg) were positively associated with the reduction in RMR (r = 0.42, p < 0.001) and metabolic adaptations (r = 0.31, p < 0.001). Metabolic adaptations were correlated with declines in leptin (r = 0.27, p < 0.01), triiodothyronine (r = 0.19, p < 0.05), and insulin (r = 0.25, p < 0.05). CONCLUSIONS: During weight loss, tissue loss and metabolic adaptations both contribute to the reduction in RMR, albeit variably. Contrary to popularly belief, it is not skeletal muscle, but rather adipose tissue losses that seem to drive RMR reductions following weight loss. Future research should target personalized strategies addressing the predominant cause of RMR reduction for weight maintenance.

The Impact of Low Energy Availability on Nonexercise Activity Thermogenesis and Physical Activity Behavior in Recreationally Trained Adults.

Energy availability describes the amount of dietary energy remaining for physiological functionality after the energy cost of exercise is deducted. The physiological and hormonal consequences of low energy availability (LEA) are well established, but the impact of LEA on physical activity behavior outside of exercise and, specifically, nonexercise activity thermogenesis (NEAT) has not been systematically examined. The authors conducted a secondary analysis of a repeated-measures crossover study in which recreationally trained young men (n = 6, 25 ± 1.0 years) underwent two 4-day conditions of LEA (15 kcal·kg fat-free mass-1 ·day-1) with and without endurance exercise (LEA + EX and LEA EX) and two energy-balanced control conditions (CON + EX and CON EX). The duration and intensity of physical activity outside of prescribed exercise were assessed using the SenseWear Pro3 armband. LEA did not alter NEAT (p = .41), nor time spent in moderate to vigorous (p = .20) and low-intensity physical activity (p = .17). However, time spent in low-intensity physical activity was lower in LEA + EX than LEA - EX (13.7 ± 0.3 vs. 15.2 ± 0.3 hr/day; p = .002). Short-term LEA does not seem to impact NEAT per se, but the way it is attained may impact physical activity behavior outside of exercise. As the participants expended similar amounts of energy during NEAT (900-1,300 kcal/day = 12.5-18.0 kcal·kg fat-free mass-1·day-1) and prescribed exercise bouts (15.0 kcal·kg fat-free mass-1·day-1), excluding it as a component of energy expenditure may skew the true energy available for physiological functionality in active populations.

The plasma protein binding of the endogenous glucocorticosteroids is of vital importance for the concentrations in hair and saliva.

BACKGROUND: The endogenous glucocorticosteroid cortisol (F) and its metabolite cortisone (E) are known to be involved in stress adaption and anti-inflammatory and immune regulatory effects. The ratios of F to E in the matrices serum, hair and saliva are different. The shift of this ratio by the enzyme activity of 11ß-hydroxysteroid-dehydrogenase, which inactivates cortisol, was often discussed. The aim of our study was to calculate the contribution of the plasma protein binding (PPB) to this shift. The PPB of F is known to be 96% of the total F-Concentration in serum. The PPB of E was not analyzed in previous studies. METHODS: Our study was designed to evaluate the correlation of corticosteroid concentrations in serum (total and free), hair and saliva. The samples were self-collected by the author (A.K.) monthly over a pregnancy cycle (1st samples before pregnancy, 8 samples during pregnancy and 5 samples postpartum). Serum protein binding was calculated from the determination of the total hormone concentrations of F and E (protein bound and unbound) and the free hormone concentrations in serum. The samples were processed by ether extraction and ultrafiltration. Hair samples were extracted with methanol and purified by solid-phase extraction. Saliva samples were collected using Salivette® collection system. The concentrations of F and E were measured by liquid chromatography-mass spectrometry with LODs for free serum, total serum, hair and saliva of F: 0.11ng/mL, 2.13ng/mL, 1.6pg/mg, 0.08ng/mL and E: 0.12ng/mL, 0.54ng/mL, 2.1pg/mg, 0.09ng/mL, respectively. RESULTS AND DISCUSSION: The serum concentrations (free and total) of both glucocorticosteroids rise up continuously during the time of pregnancy and decrease after delivery. The free and total serum concentrations were well correlated. No change was detected for the intensity of PPB of F. In contrast, the PPB of E decreases from 86.3% to 80.7% during pregnancy. The concentration ratios of F to E change from 3:1 in total serum to 1:1 in free serum. For hair samples, an increase of F and E in proximal segments was confirmed with the highest concentration 6.5weeks postpartum. Independently, corticosteroid concentrations in corresponding hair segments were found to be reduced with increasing distance from the root; an average decline of F and E by half in 5 and 6months was estimated, respectively. The counter effect of the mechanisms incorporation and wash-out is clearly visible. For saliva samples a good correlation with free, non-protein bound serum concentration was detected.

Gene expression profiling in human whole blood samples after controlled testosterone application and exercise.

Doping with anabolic agents is regulated within a number of sports. Testosterone and its functional analogs are popular compounds for increasing muscle mass, physical performance, recovery, and reducing body fat. While routine tests for anabolic drugs exist (e.g. hair, urine, and blood analysis), the aim of the present study is to determine specific gene expression profiles (induced by testosterone and exercise) which may be used as effective biomarkers to determine the use of anabolic drugs. In this study, whole blood samples of 19 male volunteers were analyzed by semi-quantitative real-time polymerase chain reaction (RT-PCR) for gene expression profiles in the context of exercise and transdermal testosterone application (1.5 mg/kg body weight). The hormone application was monitored by urine and saliva analysis for testosterone. Both urinary and saliva levels indicate that transdermal testosterone application leads to an increase of testosterone, especially after exercise. RT-PCR results showed a clear variation in the expression of target genes as well as established housekeeping genes. Only one of the nine common housekeeping genes, cyclophilin b (PPIB), appears to be independent of both exercise and testosterone. Out of 14 candidate genes, five are unregulated; all others were more or less influenced by the mentioned variables. Only interleukin-6 appeared to be exclusively dependent on long-term testosterone application. This study indicates that many genes are not influenced by testosterone alone while exercise modulates gene expression in whole blood samples. As such, exercise must be considered when validating gene expression techniques for doping analysis.