Margarita Pérez

Saliva Composition and Exercise

Little attention has been directed toward identifying the changes which occur in salivary composition in response to exercise. To address this, our article first refers to the main aspects of salivary gland physiology. A knowledge of the neural control of salivary secretion is especially important for the understanding of the effects of exertion on salivary secretion. Both salivary output and composition depend on the activity of the autonomic nervous system and any modification of this activity can be observed indirectly by alterations in the salivary excretion.The effects of physical activity (with reference to factors such as exercise intensity and duration, or type of exercise protocol) on salivary composition are then considered. Exercise might indeed induce changes in several salivary components such as immunoglobulins, hormones, lactate, proteins and electrolytes. Saliva composition might therefore be used as an alternative noninvasive indicator of the response of the different body tissues and systems to physical exertion.In this respect, the response of salivary amylase and salivary electrolytes to incremental levels of exercise is of particular interest. Beyond a certain intensity of exercise, and coinciding with the accumulation of blood lactate (anaerobic threshold or AT), a ’saliva threshold’ (Tsa) does indeed exist. Tsa is the point during exercise at which the levels of salivary α-amylase and electrolytes (especially Na+) also begin to rise above baseline levels. The occurrence of the 2 thresholds (AT and Tsa) might, in turn, be attributable to the same underlying mechanism, that of increased adrenal sympathetic activity at high exercise intensities.

Exercise training is beneficial for Alzheimer's patients

Decreased ability to perform activities of daily living (ADLs) associated with deterioration in physical capacity are key determinants of the poor quality of life and loss of independence of patients with Alzheimers disease (AD). The purpose of this study was to determine the effects of a 12-week training program (including resistance, flexibility, joint mobility and balance/coordination exercises) for Spanish patients with AD on their i) overall functional capacity (muscle strength and flexibility, agility and balance while moving, and endurance fitness), and ii) ability to perform ADLs. Using a randomized block design, 16 patients were assigned to a training (mean [SD] age: 76 [4] yrs) or control group (73 [4] yrs) (n = 8 subjects [3 male, 5 female] per group). The results showed significant improvements after training (p < 0.05) in upper and lower body muscle strength and flexibility, agility and dynamic balance, and endurance fitness (using the Senior Fitness test), gait and balance abilities (with subsequent decrease in risk of falls) (Tinetti scale) and in the ability to perform ADLs independently (Katz and Barthel scores). No changes (p > 0.05) were found in the control group over the 12-week period. Exercise training could be included in the overall medical/nursing care protocol for patients with AD.

In professional road cyclists, low pedaling cadences are less efficient.

PURPOSE To determine the effects of changes in pedaling frequency on the gross efficiency (GE) and other physiological variables (oxygen uptake (VO2), HR, lactate, pH, ventilation, motor unit recruitment estimated by EMG) of professional cyclists while generating high power outputs (PO). METHODS Following a counterbalanced, cross-over design, eight professional cyclists (age (mean +/- SD): 26 +/- 2 yr, VO2max: 74.0 +/- 5.7 mL x kg x min) performed three 6-min bouts at a fixed PO (mean of 366 +/- 37 W) and at a cadence of 60, 80, and 100 rpm. RESULTS Values of GE averaged 22.4 +/- 1.7, 23.6 +/- 1.8 and 24.2 +/- 2.0% at 60, 80, and 100 rpm, respectively. Mean GE at 100 rpm was significantly higher than at 60 rpm (P < 0.05). Similarly, mean values of VO2, HR, rates of perceived exertion (RPE), lactate and normalized root-mean square EMG (rms-EMG) in both vastus lateralis and gluteus maximum muscles decreased at increasing cadences. CONCLUSIONS In professional road cyclists riding at high PO, GE/economy improves at increasing pedaling cadences.

Exercise during Hematopoietic Stem Cell Transplant Hospitalization in Children

PURPOSE The purpose of this controlled trial was to assess the effect of an approximately 3-wk intrahospital exercise intervention performed during inpatient hospitalization for pediatric allogeneic hematopoietic stem cell transplant (HSCT) on (i) immune cell recovery and (ii) body composition. METHODS Immune (i.e., blood counts of leukocytes, monocytes, lymphocytes, and lymphocyte subpopulations) and anthropometric variables (i.e., body mass, body mass index, and estimated fat-free mass) were measured before and after (+15 and 30 d) HSCT. Seven children (5 boys and 2 girls; age (mean +/- SD) = 8 +/- 4 yr) with high-risk cancer performed an individualized training program (aerobic + resistance exercises) in their isolated hospital rooms. We also assessed a control group (n = 13; 9 boys and 4 girls; age = 7 +/- 3 yr) with similar medical conditions and following the same transplant protocol. RESULTS In both groups, the dendritic cell count decreased from pre-HSCT to +15 d post-HSCT and thereafter (up to +30 d) remained stabile; however, the posttransplant decrease was more abrupt in the control group than that in the intervention group (-87% vs -63%, respectively, from pre-HSCT to +15 d). The rest of the immune cell parameters measured showed a similar response from pre-HSCT to post-HSCT in both groups. We found a significant effect of the interaction group x time for all anthropometric variables (weight, body mass index, body fat, and fat-free mass), indicating an increase over the hospitalization period only in the intervention group, for example, body mass increased from 32.9 +/- 18.7 kg pre-HSCT to 35.4 +/- 18.6 kg at +30 d in the intervention group versus a decrease from 30.2 +/- 16.6 to 29.3 +/- 6.3 kg in the control group. CONCLUSION Our findings support the feasibility of exercise training interventions during hospitalization, including immunocompromised children.

Kinetics of VO(2) in professional cyclists.

PURPOSE To analyze the kinetics of oxygen uptake (VO(2)) in professional road cyclists during a ramp cycle ergometer test and to compare the results with those derived from well-trained amateur cyclists. METHODS Twelve professional cyclists (P group; 25 +/- 1 yr; maximal power output (W(max)), 508.3 +/- 9.3 watts) and 10 amateur cyclists (A group; 22 +/- 1 y; W(max), 429.9 +/- 8.6 watts) performed a ramp test until exhaustion (power output increases of 25 watts x min(-1)). The regression lines of the VO(2):power output (W) relationship were calculated for the following three phases: phase I (below the lactate threshold (LT)), phase II (between LT and the respiratory compensation point (RCP)), and phase III (above RCP). RESULTS In group P, the mean slope (Delta VO(2):Delta W) of the VO(2):W relationship decreased significantly (P < 0.01) across the three phases (9.9 +/- 0.1, 8.9 +/- 0.2, and 3.8 +/- 0.6 mL O(2) x watts(-1) x min(-1) for phases I, II, and III, respectively). No significant differences (P > 0.05) were found between phases I and II (P > 0.05) in group A, whereas Delta VO(2):Delta W significantly increased in phase III (P < 0.01), compared with phase II (10.2 +/- 0.3, 9.2 +/- 0.4, and 10.1 +/- 1.1 mL O(2) x watts(-1) x min(-1) in phases I, II, and III, respectively). The mean value of Delta VO(2):Delta W for phase III was significantly lower in group P than in group A (P < 0.01). CONCLUSION Contrary to the case in amateur riders, the rise in VO(2) in professional cyclists is attenuated at moderate to high workloads. This is possibly an adaptation to the higher demands of their training/competition schedule.

Immunolabelling, histochemistry and in situ hybridisation in human skeletal muscle fibres to detect myosin heavy chain expression at the protein and mRNA level

The distribution of muscle fibres classified on the basis of their content of different myosin heavy chain (MHC) isoforms was analysed in vastus lateralis muscle biopsies of 15 young men (with an average age of 22 y) by correlating immunohistochemistry with specific anti‐MHC monoclonal antibodies, myofibrillar ATPase (mATPase) histochemistry and in situ hybridisation with probes specific for MHC β‐slow, MHC‐IIA and MHC‐IIX. The characterisation of a large number of individual fibres was compared and correlated on a fibre‐to‐fibre basis. The panel of monoclonal antibodies used in the study allowed classification of human skeletal muscle fibres into 5 categories according to the MHC isoform they express at the protein level, types I, I+IIA, IIA, IIAX and IIX. Hybrid fibres coexpressing two isoforms represented a considerable proportion of the fibre composition (about 14%) and were clearly underestimated by mATPase histochemistry. For a very high percentage of fibres there was a precise correspondence between the MHC protein isoforms and mRNA transcripts. The integrated methods used demonstrate a high degree of precision of the immunohistochemical procedure used for the identification and quantification of human skeletal muscle fibre types. The monoclonal antibody S5‐8H2 is particularly useful for identifying hybrid IIAX fibres. This protocol offers new prospects for muscle fibre classification in human experimental studies.

The I allele of the ACE gene is associated with improved exercise capacity in women with McArdle disease

We assessed the possible association existing between alpha-actinin-3 (ACTN3) R577X genotypes and the capacity for performing aerobic exercise in McArdles patients. Forty adult McArdles disease patients and forty healthy, age and gender-matched sedentary controls (21 men, 19 women in both groups) performed a graded test until exhaustion and a constant-load test on a cycle-ergometer to determine clinically relevant indices of exercise capacity as peak oxygen uptake (VO(2peak)) and the ventilatory threshold (VT). In the group of diseased women, carriers of the X allele had a higher (P<0.01) VO(2peak) (15.0+/-1.2 ml/kg/min) and a higher (P<0.05) oxygen uptake (VO(2)) at the VT (11.2+/-1 ml/kg/min) than R/R homozygotes (VO(2peak): 9.6+/-0.5 ml/kg/min; VO(2) at the VT: 8.2+/-0.7 ml/kg/min). No differences were found in male patients. In women with McArdles disease, ACTN3 genotypes might partly explain the large individual variability that exists in the phenotypic manifestation of this disorder.

Is Cardiorespiratory Fitness Related to Quality of Life in Survivors of Breast Cancer

The purpose of this study was to investigate whether indices of cardiorespiratory fitness are related to quality of life (QOL) in women survivors of breast cancer. Using the European Organization for Research and Treatment of Cancer QLQ-30 questionnaire, we assessed the QOL of 16 participants (age, 50 ± 9 years; body mass, 66.6 ± 9.6 kg). All participants performed incremental cycle ergometer exercise to determine several indices of cardio-respiratory fitness (e.g., peak oxygen uptake [&OV0312;O2peak, in L·min−1, ml·kg−1·min−1]), peak power output (PPO, in W), PPO/ body mass (W·kg−1), peak heart rate (HRpeak, b·min−1), peak ventilation (VEpeak), and &OV0312;O2 and heart rate (HR) at the ventilatory (VT) and respiratory compensation (RCT) thresholds. Relationships between QOL and variables were assessed using Spearman rank-difference correlation tests. A significant inverse relationship (p < 0.05) was found for QOL scores and values for age (years) and body mass (kg) (ρ = −0.53), %HRpeak@VT (ρ = −0.59) and %VEpeak@VT (ρ = −0.61). A significant positive relationship (p < 0.05) was found for QOL and PPO/body mass (ρ =0.59) and HRpeak (ρ = 0.78), &OV0312;O2@RCT (ml·kg−1·min−1)(ρ = 0.51), power output (PO, expressed as either W or W·kg−1) at RCT, and HR at RCT (ρ = 0.54). No other significant relationship was found between QOL and variables obtained from the tests. In conclusion, these findings highlight possible relationships between cardiorespiratory fitness and well-being in survivors of breast cancer. From a practical point of view, our data emphasize the need for this population to engage in programmed cardiorespiratory exercise training, mainly designed to improve VT and RCT. The improvement of both submaximal indices can have a beneficial effect on QOL.

Genotype modulators of clinical severity in McArdle disease.

The phenotypic manifestation of McArdle disease varies considerably from one individual to the next. The purpose of this study was to assess the possible association between the clinical severity of the disease, and each of the genotypes PYGM (R50X), ACE (I/D), AMPD1 (Q12X), PPARGC1A (G482S) and ACTN3 (R577X). We also assessed links between clinical disease severity and other potential phenotype modulators such as age or gender. McArdle disease was diagnosed in 99 patients of Spanish origin (60 male, 39 female; age range 8-81 years) by identifying the two mutant alleles of the PYGM gene. Disease severity was assessed using the grading scheme previously reported by Martinuzzi et al. [A. Martinuzzi, E. Sartori, M. Fanin, et al., Phenotype modulators in myophosphorylase deficiency, Ann. Neurol. 53 (2003) 497-502]. Significant correlation was observed (exact two-sided P<0.0001) between the number of D alleles of the ACE gene and the disease severity score. Rank-order correlation coefficients were 0.296 (95% CI: 0.169, 0.423) (Kendalls tau) and 0.345 (95% CI: 0.204, 0.486) (Somers D). No significant relationships were detected between clinical severity and the remaining genotypes examined. Finally, disease severity was significantly worse in women with the disease. Our findings indicate that both ACE genotype and gender contribute to how McArdle disease manifests in an individual patient. The role of other candidate genes remains to be elucidated.

Intrahospital Weight and Aerobic Training in Children with Cystic Fibrosis: A Randomized Controlled Trial

PURPOSE The purpose of our study was to assess the effects of an 8-wk intrahospital combined circuit weight and aerobic training program performed by children with cystic fibrosis (of low-moderate severity and stable clinical condition) on the following outcomes: cardiorespiratory fitness (VO2peak) and muscle strength (five-repetition maximum (5RM) bench press, 5RM leg press, and 5RM seated row) (primary outcomes) and pulmonary function (forced vital capacity, forced expiratory volume in 1 s), weight, body composition, functional mobility (Timed Up and Down Stairs and 3-m Timed Up and Go tests), and quality of life (secondary outcomes). We also determined the effects of a detraining period (4 wk) on the aforementioned outcomes. METHODS We performed a randomized controlled trial design. Eleven participants in each group (controls: 7 boys, age = 11 ± 3 yr, body mass index = 17.2 ± 0.8 kg · m(-2) (mean ± SEM); intervention: 6 boys, age = 10 ± 2 yr, body mass index = 18.4 ± 1.0 kg · m(-2)) started the study. RESULTS Adherence to training averaged 95.1% ± 7.4%. We observed a significant group × time interaction effect (P = 0.036) for VO2peak. In the intervention group, VO2peak significantly increased with training by 3.9 mL · kg(-1) · min(-1) (95% confidence interval = 1.8-6.1 mL · kg(-1) · min(-1), P = 0.002), whereas it decreased during the detraining period (-3.4 mL · kg(-1) · min(-1), 95% confidence interval = -5.7 to -1.7 mL · kg(-1) · min(-1), P = 0.001). In contrast, no significant changes were observed during the study period within the control group. Although significant improvements were also observed after training for all 5RM strength tests (P < 0.001 for the interaction effect), the training improvements were not significantly decreased after the detraining period in the intervention group (all P > 0.1 for after training vs detraining). We found no significant training benefits in any of the secondary outcomes. CONCLUSIONS A short-term combined circuit weight and aerobic training program performed in a hospital setting induces significant benefits in the cardiorespiratory fitness and muscle strength of children with cystic fibrosis.