Continuous versus intermittent exercise effects on urinary excretion of albumin and total protein.

Several studies have reported post-exercise increases of urinary concentrations of plasma proteins. However, under normal conditions, through mechanisms of size and electrical charge selection, the kidney restricts the clearance of molecules as large as albumin. Post-exercise increases in albuminuria occur following the physiological stress of intense exercise, most likely as a result of the exercise induced blood acidity changes which lead to a change in the arrangement of the albumin molecule, and subsequently the filtration characteristics of the glomerular capillary wall. The purpose of the present study was therefore to determine the extent to which different types of exercise could induce a transient condition of post-exercise increases in the urinary output of total protein and albumin. All 14 males, who agreed to participate in the study, performed a continuous and an intermittent cycling protocol on a stationary bicycle ergometer. The results showed that: a) intermittent exercise had a greater influence than continuous exercise on the total output of urine albumin, and of urine total protein; b) concentrations of blood pH and blood lactate, were associated with changes in the clearance of urine albumin and urine total protein. Post-exercise proteinuria response seems to be transient and therefore renal trauma is not suspected at the early stages of observation. Furthermore, these results indicate that the kidney undergoes distinct physiological adjustments during exercise, and that these adjustments are relative to the intensity of the exercise stress.

Intercollegiate ice hockey injuries. A case for uniform definitions and reports.

The lack of agreement on definition of terms and consistent reporting strategies in sports epidemiology complicates the determination of injury rates in any sport. This study describes Canadian Intercollegiate ice hockey injuries over a 6-year period by following a standardized reporting strategy and clearly defined terminology. Overall, the data show that the knee is most susceptible to injury, that the forwards recorded the highest number of injuries, and that body contact caused the majority of injuries. Compared to other studies the results indicate a decreasing per game injury rate over the last 15 years and provide evidence that helmets and visors reduce the risk of head and facial injuries. Recommendations are propagated toward the adherence of standardized reporting strategies and uniform definitions to be used in future sports injury epidemiologic research.

Evaluating the influence of sleep deprivation upon circadian rhythms of exercise metabolism.

Cardiorespiratory and gas exchange responses to a moderate, standardized treadmill walking task showed a weak circadian rhythm, with larger superimposed peaks attributable to feeding. However, both rhythms became progressively attenuated during a period of sleep deprivation. A method of exploring this phenomenon is illustrated by an analysis of data on walking heart rate, respiratory minute volume, oxygen intake, and rating of perceived exertion, collected on 11 young men at 3-hr intervals during 60 hours of sleep deprivation.