Sex Differences in Physiological Stress Induced by a Long-Lasting Adventure Race: A Prospective Observational Analytical Study.

BACKGROUND: In order to provide additional information on the behaviour of biochemical parameters related to stress responses to a specific long-term competition, we aimed to compare the stressful effects of a long-lasting competition on physiological variables in men and women. METHODS: This is a prospective observational analytical study. Twenty-five professional athletes, 15 men and 10 women, travelled 460 km for 4 days in an international edition of the Ecomotion/Pro AR World. RESULTS: After the competition, we detected an increase in α-amylase and cortisol levels and a decrease in salivary immunoglobulin A (lgA) levels. The relative percentage changes in α-amylase, IgA and cortisol levels were significantly higher in women than in men, whereas women had lower relative percentage changes in glucose and lactate levels compared with men. There was a decrease in lymphocyte, eosinophil and monocyte counts, with relative percentage decreases in lymphocytes and monocytes being significantly higher in female athletes than in males. There were increases in the serum activities of total creatine kinase (CK), the creatine kinase myocardial isoform (CKMB), alanine aminotransferase (ALT), aspartate aminotransferase (AST) and lactate dehydrogenase (LDH) at the end of the test, with significantly higher elevations of total CK, CKMB and LDH in men and ALT in women. CONCLUSION: Long-lasting competition induced stress, muscle damage, anaemia and changes in the immune system. Women had more intense responses of cortisol and leukocytes.

Evaluation of the effects of aerobic training during hemodialysis on autonomic heart rate modulation in patients with chronic renal disease.

INTRODUCTION: Chronic renal disease (CRD) affects a large portion of the population and is directly related to cardiovascular problems and hypertension, among others. Studies show that heart rate variability is directly affected by these problems. Physical-oriented exercises have been shown to be of fundamental importance in improving the adverse effects to dialysis treatment. OBJECTIVE: To analyze the effects of aerobic training during hemodialysis on autonomic heart rate modulation in patients with CRD. METHOD: Experimental study of an open, single group clinical trial. In this clinical trial, patients with CRD will initially undergo international physical activity questionnaire and kidney disease quality of life short form protocols, as well as monitoring of heart rate systolic, and diastolic blood pressure. After evaluation of the initial parameters, patients will undergo an aerobic exercise program for 12 weeks, in 3 weekly sessions, lasting 30 minutes a session. These evaluations will allow for a greater control of the disease, and monitoring of any improvements in the quality of life and self-esteem of these patients. ETHICS AND DISSEMINATION: This study was approved following the guidelines and norms that regulate research involving human subjects, in Resolution No. 466/12 of the National Health Council. It was approved by the Research Ethics Committee of the Faculty of Juazeiro do Norte, with the number 1962 092. All patients who agree to participate in the research will sign the informed consent form. The results will be disseminated through peer-reviewed journal articles and conferences.

Correction: The influence of a hot environment on physiological stress responses in exercise until exhaustion.

[This corrects the article DOI: 10.1371/journal.pone.0209510.].

The influence of a hot environment on physiological stress responses in exercise until exhaustion.

Exhaustive exercise in a hot environment can impair performance. Higher epinephrine plasma levels occur during exercise in heat, indicating greater sympathetic activity. This study examined the influence of exercise in the heat on stress levels. Nine young healthy men performed a maximal progressive test on a cycle ergometer at two different environmental conditions: hot (40°C) and normal (22°C), both between 40% and 50% relative humidity. Venous blood and saliva samples were collected pre-test and post-test. Before exercise there were no significant changes in salivary biomarkers (salivary IgA: p = 0.12; α-amylase: p = 0.66; cortisol: p = 0.95; nitric oxide: p = 0.13; total proteins: p = 0.07) or blood lactate (p = 0.14) between the two thermal environments. Following exercise, there were significant increases in all variables (salivary IgA 22°C: p = 0.04, 40°C: p = 0.0002; α-amylase 22°C: p = 0.0002, 40°C: p = 0.0002; cortisol 22°C: p = 0.02, 40°C: p = 0.0002; nitric oxide 22°C: p = 0.0005, 40°C: p = 0.0003, total proteins 22°C: p<0.0001, 40°C: p<0.0001 and; blood lactate 22°C: p<0.0001, 40°C: p<0.0001) both at 22°C and 40°C. There was no significant adjustment regarding IgA levels between the two thermal environments (p = 0.74), however the levels of α-amylase (p = 0.02), cortisol (p<0.0001), nitric oxide (p = 0.02) and total proteins (p = 0.01) in saliva were higher in the hotter conditions. Blood lactate was lower under the hot environment (p = 0.01). In conclusion, enduring hot temperature intensified stressful responses elicited by exercise. This study advocates that hot temperature deteriorates exercise performance under exhaustive stress and effort conditions.