I am calling attention to three articles in this month’s issue of MSSE. The first of these is a review article by Kenney, Craighead, and Alexander, based on Kenney’s President’s Lecture on changing climate from last year’s annual ACSM meeting. Climate change has the potential to influence human health because it increases the frequency and severity of heat waves, with the elderly being most affected. Ample evidence demonstrates that passive heat stress places strain on the left ventricle. When one couples the increasing number of individuals over the age of 70 with global warming, cardiovascular deaths precipitated by periods of high ambient temperatures are of increasing concern. In association with this review, we are making freely available a highly cited article by Galloway and Maughan [Effects of Ambient Temperature on the Capacity to Perform Prolonged Cycle Exercise in Man. Med Sci Sports Exerc. 1997;29(9):1240-1249].
Hypoxic training is commonly used but its beneficial effects for performance at sea level remains controversial, and poorly documented for moderate altitude. Robach et al. report that six weeks of hypoxic training generally had little effect on the respiratory capacity of skeletal muscle, VO2peak, or time trial performance. However, in acute hypoxic conditions, time trial performance tended to increase more following hypoxic training, suggesting that hypoxic training may facilitate endurance capacity at moderate altitude. This tendency encourages further controlled research on endurance performance at moderate altitude following hypoxic training interventions. As an adjunct to this report, we are making freely available an article by Melissa et al. [Skeletal muscle adaptations to training under normobaric hypoxic versus normoxic conditions. Med Sci Sports Exerc. 1997;29(2):238-243].
Finally, Shaw and colleagues evaluated the validity of oxygen cost as a measure of running economy in trained distance runners. Their take-home message was that oxygen cost alone does not provide a valid index of the underlying energy cost, not surprisingly because it fails to account for alterations in substrate metabolism. Given that calculation of energy cost requires no additional demands to be placed on the athlete beyond those imposed to assess gas exchange, they propose that energy cost should be employed as the primary measure of running economy, and should simply be expressed relative to body mass (i.e., kcal∙kg-1∙km-1) to enable accurate interindividual comparisons. For historical perspective, we are making freely available an article by Howley and Glover that used classical techniques [The Caloric Costs of Running and Walking One Mile for Men and Women. Med Sci Sports Exerc. 1974;6(4):235-237].
L. Bruce Gladden