Metabolic muscle damage and oxidative stress markers in an America’s Cup yachting crew

Effects of an Offshore Sailing Competition on Anthropometry, Muscular Performance, Subjective Wellness, and Salivary Cortisol in Professional Sailors

INTRODUCTION

Evidence regarding the impact of offshore sailing on fatigue and readiness variables is conspicuous by its absence. This study investigated the acute effects of an offshore sailing regatta on anthropometry, muscular performance, subjective recovery, and salivary biomarker cortisol.

METHODS

Ten professional offshore sailors from a mixed-sex crew partook in the study (N = 10; mean [SD] age = 32.2 [3.96] y; stature = 179.1 [7.30] cm; body mass = 84.2 [12.1] kg). The race involved 3 offshore legs over a 3-week period. Baseline measures of anthropometry, lower- and upper-body muscular function, perceptions of subjective wellness, and salivary cortisol were assessed 3 hours prior to competition (ie, before the first leg). These measures were repeated within 30 minutes after the cessation of each leg. During each leg, boat movements were recorded via global positioning system units.

RESULTS

There were significant reductions in lower (effect size [ES] = 0.49) and upper muscular (ES = 0.21) functions, as well as in subjective wellness (ES = 1.65). Salivary cortisol levels increased (ES = 0.84).

CONCLUSION

These results demonstrate that, during an intensified period of sailing competition, fatigue will progressively increase. This may impede sailing performance by reducing physical and cognitive efficiency. Furthermore, countermovement jump, handgrip strength, perception of subjective wellness, and cortisol concentration appear to be sensitive measures for monitoring fatigue and readiness in professional sailors.

Oxidative stress and motion sickness in one crew during competitive offshore sailing

Competitive Offshore Ocean Sailing is a highly demanding activity in which subjects are exposed to psychophysical stressors for a long time. To better define the physiological adaptations, we investigated the stress response of subjects exposed to 3-days long ocean navigation with disruption of circadian rhythms. 6 male subjects were involved in the study and provided urine and saliva samples before setting sail, during a single day of inshore sailing, during 3-days long ocean navigation, and at the arrival, to measure oxidative stress, cortisol, nitric oxide metabolites (NOx) and metabolic response. Motion Sickness questionnaires were also administered during the navigation. The crew suffered a mean weight loss of 1.58 kg. After the long navigation, a significant increase in ROS production and decrease in total antioxidant capacity and uric acid levels were observed. Lipid peroxidation, NO metabolites, ketones, creatinine, and neopterin levels were also increased. Furthermore, a significant increase in cortisol levels was measured. Finally, we found a correlation between motion sickness questionnaires with the increase of NOx, and no correlation with cortisol levels. Physical and psychological stress response derived from offshore sailing resulted in increased oxidative stress, nitric oxide metabolites, and cortisol levels, unbalanced redox status, transient renal function impairment, and ketosis. A direct correlation between motion sickness symptoms evaluated through questionnaires and NOx levels was also found.

Shortage of Cellular ATP as a Cause of Diseases and Strategies to Enhance ATP

Germline mutations in cellular-energy associated genes have been shown to lead to various monogenic disorders. Notably, mitochondrial disorders often impact skeletal muscle, brain, liver, heart, and kidneys, which are the body’s top energy-consuming organs. However, energy-related dysfunctions have not been widely seen as causes of common diseases, although evidence points to such a link for certain disorders. During acute energy consumption, like extreme exercise, cells increase the favorability of the adenylate kinase reaction 2-ADP -> ATP+AMP by AMP deaminase degrading AMP to IMP, which further degrades to inosine and then to purines hypoxanthine -> xanthine -> urate. Thus, increased blood urate levels may act as a barometer of extreme energy consumption. AMP deaminase deficient subjects experience some negative effects like decreased muscle power output, but also positive effects such as decreased diabetes and improved prognosis for chronic heart failure patients. That may reflect decreased energy consumption from maintaining the pool of IMP for salvage to AMP and then ATP, since de novo IMP synthesis requires burning seven ATPs. Similarly, beneficial effects have been seen in heart, skeletal muscle, or brain after treatment with allopurinol or febuxostat to inhibit xanthine oxidoreductase, which catalyzes hypoxanthine -> xanthine and xanthine -> urate reactions. Some disorders of those organs may reflect dysfunction in energy-consumption/production, and the observed beneficial effects related to reinforcement of ATP re-synthesis due to increased hypoxanthine levels in the blood and tissues. Recent clinical studies indicated that treatment with xanthine oxidoreductase inhibitors plus inosine had the strongest impact for increasing the pool of salvageable purines and leading to increased ATP levels in humans, thereby suggesting that this combination is more beneficial than a xanthine oxidoreductase inhibitor alone to treat disorders with ATP deficiency.

[Allopurinol and its role in the treatment of sarcopenia]

Xanthine oxidase (XO) is an enzyme that catalyzes the oxidation of hypoxanthine to xanthine and uric acid and plays an important role in purine catabolism. The purine analogue, allopurinol, is a well-known inhibitor of XO widely used in the clinical management of gout and conditions associated with hyperuricemia. More recent data indicate that allopurinol reduces oxidative stress and improves vascular function in several cardiometabolic diseases, prolongs exercise time in angina, and improves the efficiency of cardiac contractility in heart failure. XO also plays an important role in free radical generation during skeletal muscle contraction and thus, it has been related to the muscle damage associated to exhaustive exercise. Several research groups have shown the protective effect of allopurinol in the prevention of this type of damage. Based on this background, a critical overview is presented on the possible role of allopurinol in the treatment of sarcopenia, a geriatric syndrome characterized by progressive and generalized loss of skeletal muscle mass and strength with a risk of adverse outcomes, such as physical disability, poor quality of life and death.

Effects of high-intensity training and resumed training on macroelement and microelement of elite basketball athletes

The purpose of this study was to assess the effects of high-intensity training and resumed training in hot and humid environment on plasma macro- and microelements levels of elite Han Chinese basketball players. Ten well-trained elite basketball athletes' plasma macroelements (chlorin, sodium, potassium, and calcium), creatine kinase (CK), and creatine kinase-MB (CK-MB) were measured before and after a 2-h high-intensity training, and microelements (zinc, copper, iron, and selenium) were determined before and after a 1-week high-intensity training and after a 1-week resumed training. The blood CK and CK-MB levels of the elite basketball athletes were significantly increased (P < 0.05) after high-intensity basketball training. The macroelements (chlorin, sodium, and calcium) levels of blood increased significantly except potassium after high-intensity basketball training. No significant differences (P > 0.05) were found in zinc and copper levels; nevertheless, the levels of plasma selenium and plasma iron were significantly lower (P < 0.05) after a 1-week high-intensity training. After a 1-week resumed training, except zinc, all of microelements measured had a trend toward original levels. These results implicated that high-intensity training would provoke the change of macroelements which would lead to electrolyte disturbance. In addition, the present study suggested that a 1-week high-intensity training would have an impact on microelement levels, especially for selenium and iron.