Effect of a resistance exercise at acute moderate altitude on muscle health biomarkers.

The intensification of the stress response during resistance training (RT) under hypoxia conditions could trigger unwanted effects that compromise muscle health and, therefore, the ability of the muscle to adapt to longer training periods. We examined the effect of acute moderate terrestrial hypoxia on metabolic, inflammation, antioxidant capacity and muscle atrophy biomarkers after a single RT session in a young male population. Twenty healthy volunteers allocated to the normoxia (N < 700 m asl) or moderate altitude (HH = 2320 m asl) group participated in this study. Before and throughout the 30 min following the RT session (3 × 10 reps, 90 s rest, 70% 1RM), venous blood samples were taken and analysed for circulating calcium, inorganic phosphate, cytokines (IL-6, IL-10 and TNF-α), total antioxidant capacity (TAC) and myostatin. Main results displayed a marked metabolic stress response after the RT in both conditions. A large to very large proportional increase in the adjusted to pre-exercise change of inflammatory and anti-inflammatory markers favoured HH (serum TNF-α [ES = 1.10; p = 0.024] and IL-10 [ES = 1.31; p = 0.009]). The exercise produced a similar moderate increment of myostatin in both groups, followed by a moderate non-significant reduction in HH throughout the recovery (ES = - 0.72; p = 0.21). The RT slightly increased the antioxidant response regardless of the environmental condition. These results revealed no clear impact of RT under acute hypoxia on the metabolic, TAC and muscle atrophy biomarkers. However, a coordinated pro/anti-inflammatory response balances the potentiated effect of RT on systemic inflammation.

Therapeutic approach for digestive system cancers and potential implications of exercise under hypoxia condition: what little is known? a narrative review.

BACKGROUND: Cancer, like other chronic pathologies, is associated with the presence of hypoxic regions due to the uncontrolled cell growth. Under this pathological hypoxic condition, various molecular signaling pathways are activated to ensure cell survival, such as those that govern angiogenesis, erythropoiesis, among others. These molecular processes are very similar to the physiological response caused by exposure to altitude (natural hypobaric systemic hypoxia), the use of artificial hypoxia devices (systemic normobaric simulated hypoxia) or the delivery of vascular occlusion to the extremities (also called local hypoxia by the blood flow restriction technique). "Tumor hypoxia" has gained further clinical importance due to its crucial role in both tumor progression and resistance to treatment. However, the ability to manipulate this pathway through physical exercise and systemic hypoxia-mediated signaling pathways could offer an important range of therapeutic opportunities that should be further investigated. METHODS: This review is focused on the potential implications of systemic hypoxia combined with exercise in digestive system neoplasms prognosis. Articles included in the review were retrieved by searching among the three main scientific databases: PubMed, Scopus, and Embase. FINDINGS: The findings of this review suggest that exercise performed under systemic hypoxic conditions could have a positive impact in prognosis and quality of life of the population with digestive system cancers. CONCLUSIONS: Further studies are needed to consider this paradigm as a new potential intervention in digestive oncological population.

Hormonal and Inflammatory Responses to Hypertrophy-Oriented Resistance Training at Acute Moderate Altitude.

This study investigated the effect of a traditional hypertrophy-oriented resistance training (RT) session at acute terrestrial hypoxia on inflammatory, hormonal, and the expression of miR-378 responses associated with muscular gains. In a counterbalanced fashion, 13 resistance trained males completed a hypertrophic RT session at both moderate-altitude (H; 2320 m asl) and under normoxic conditions (N; <700 m asl). Venous blood samples were taken before and throughout the 30 min post-exercise period for determination of cytokines (IL6, IL10, TNFα), hormones (growth hormone [GH], cortisol [C], testosterone), and miR-378. Both exercise conditions stimulated GH and C release, while miR-378, testosterone, and inflammatory responses remained near basal conditions. At H, the RT session produced a moderate to large but nonsignificant increase in the absolute peak values of the studied cytokines. miR-378 revealed a moderate association with GH (r = 0.65; p = 0.026 and r = -0.59; p = 0.051 in N and H, respectively) and C (r = 0.61; p = 0.035 and r = 0.75; p = 0.005 in N and H, respectively). The results suggest that a RT session at H does not differentially affect the hormonal, inflammatory, and miR-378 responses compared to N. However, the standardized mean difference detected values in the cytokines suggest an intensification of the inflammatory response in H that should be further investigated.

Supplementation with a Mango Leaf Extract (Zynamite®) in Combination with Quercetin Attenuates Muscle Damage and Pain and Accelerates Recovery after Strenuous Damaging Exercise.

Prolonged or unusual exercise may cause exercise-induced muscle damage (EIMD). To test whether Zynamite®, a mango leaf extract rich in the natural polyphenol mangiferin, administered in combination with quercetin facilitates recovery after EIMD, 24 women and 33 men were randomly assigned to two treatment groups matched by sex and 5 km running performance, and ran a 10 km race followed by 100 drop jumps to elicit EIMD. One hour before the competition, and every 8 hours thereafter for 24 hours, they ingested placebo (728 mg of maltodextrin) or 140 mg of Zynamite® combined with 140 mg of quercetin (double-blind). Although competition times were similar, polyphenol supplementation attenuated the muscle pain felt after the competition (6.8 ± 1.5 and 5.7 ± 2.2 a.u., p = 0.035) and the loss of jumping performance (9.4 ± 11.5 and 3.9 ± 5.2%, p = 0.036; p = 0.034) and mechanical impulse (p = 0.038) 24 hours later. The polyphenols attenuated the increase of serum myoglobin and alanine aminotransferase in men, but not in women (interaction p < 0.05). In conclusion, a single dose of 140 mg Zynamite® combined with 140 mg of quercetin, administered one hour before competition, followed by three additional doses every eight hours, attenuates muscle pain and damage, and accelerates the recovery of muscle performance.

Exercise Mitigates the Loss of Muscle Mass by Attenuating the Activation of Autophagy during Severe Energy Deficit.

The loss of skeletal muscle mass with energy deficit is thought to be due to protein breakdown by the autophagy-lysosome and the ubiquitin-proteasome systems. We studied the main signaling pathways through which exercise can attenuate the loss of muscle mass during severe energy deficit (5500 kcal/day). Overweight men followed four days of caloric restriction (3.2 kcal/kg body weight day) and prolonged exercise (45 min of one-arm cranking and 8 h walking/day), and three days of control diet and restricted exercise, with an intra-subject design including biopsies from muscles submitted to distinct exercise volumes. Gene expression and signaling data indicate that the main catabolic pathway activated during severe energy deficit in skeletal muscle is the autophagy-lysosome pathway, without apparent activation of the ubiquitin-proteasome pathway. Markers of autophagy induction and flux were reduced by exercise primarily in the muscle submitted to an exceptional exercise volume. Changes in signaling are associated with those in circulating cortisol, testosterone, cortisol/testosterone ratio, insulin, BCAA, and leucine. We conclude that exercise mitigates the loss of muscle mass by attenuating autophagy activation, blunting the phosphorylation of AMPK/ULK1/Beclin1, and leading to p62/SQSTM1 accumulation. This includes the possibility of inhibiting autophagy as a mechanism to counteract muscle loss in humans under severe energy deficit.

Accuracy and Precision of the COSMED K5 Portable Analyser.

The main aims of this study were to determine the accuracy of the portable metabolic cart K5 by comparison with a stationary metabolic cart (Vyntus CPX), to check on the validity of Vyntus CPX using a butane combustion test, and to assess the reliability of K5 during prolonged walks in the field. For validation, measurements were consecutively performed tests with both devices at rest and during submaximal exercise (bicycling) at low (60 W) and moderate intensities (130-160 W) in 16 volunteers. For the reliability study, 14 subjects were measured two times during prolonged walks (13 km, at 5 km/h), with the K5 set in mixing chamber (Mix) mode. Vyntus measured the stoichiometric RQ of butane combustion with high accuracy (error <1.6%) and precision (CV <0.5%), at VO2 values between 0.788 and 6.395 L/min. At rest and 60 W, there was good agreement between Vyntus and K5 (breath-by-breath, B×B) in VO2, VCO2, RER, and energy expenditure, while in Mix mode the K5 overestimated VO2 by 13.4 and 5.8%, respectively. Compared to Vyntus, at moderate intensity the K5 in B×B mode underestimated VO2, VCO2, and energy expenditure by 6.6, 6.9, and 6.6%, respectively. However, at this intensity there was an excellent agreement between methods in RER and fat oxidation. In Mix mode, K5 overestimated VO2 by 5.8 and 4.8%, at 60 W and the higher intensity, respectively. The K5 had excellent reliability during the field tests. Total energy expenditure per Km was determined with a CV for repeated measurements of 4.5% (CI: 3.2-6.9%) and a concordance correlation coefficient of 0.91, similar to the variability in VO2. This high reproducibility was explained by the low variation of FEO2 measurements, which had a CV of 0.9% (CI: 0.7-1.5%) combined with a slightly greater variability of FECO2, VE, VCO2, and RER. In conclusion, the K5 is an excellent portable metabolic cart which is almost as accurate as a state-of-art stationary metabolic cart, capable of measuring precisely energy expenditure in the field, showing a reliable performance during more than 2 h of continuous work. At high intensities, the mixing-chamber mode is more accurate than the B×B mode.