Lessons from the Iditarod(hat are found in human endurance athlete...)

Date:9/24/2008

hat are found in human endurance athletes during their first day of exercise, including depletion of muscle energy reserves, increases in stress hormones, evidence of cellular injury (such as to proteins, lipids and DNA), and oxidative stress. However, with subsequent consecutive days of exercise at the same intensity, these changes are reversed. Within four days after exercise begins, the metabolic profile of the dogs returns to where it was before the race began, despite their sustained, strenuous exercise. When human ultra-athletes become fatigued, they stay that way until a period of recovery that may take a full day.

• Enormous Aerobic CapacityRacing sled dogs have enormous aerobic capacity. While the untrained sled dogs have an average aerobic capacity of 175 ml/kg/min VO2 max (ratio of volume of oxygen to body weight per minute), the aerobic capacity of the fully conditioned sled dogs is estimated to be about twice that (300 ml/kg/min).

• Using A High-Fat Diet to Fuel ExerciseDuring periods of racing, sled dogs can burn up to 12,000 kilocalories per day (kcal/day). This means that a 55-pound sled dog will consume the equivalent of 24 McDonald's Big Macs to fuel their run on any given day. Some of the running dog's high-fat diet is converted to energy in the liver, and used as fuel in the initial stages of exercise. Preliminary data suggests that this process is a desirable trait intended to efficiently support exercise in the racers. It is worth noting that humans would need 72 Big Macs to fuel the power they need to make a day's run, assuming their body could absorb and process all the fat contained in the beef.

Next Steps

The mechanisms that make these four-legged athletes premiere in performance is still unknown. Dr. Davis theorizes that it may involve the regulation of extremely thin membranes in the muscle fibers and changes in the cells that are responsible for the body's energy produc
'/>"/>

Contact: Donna Krupa DKrupa@The-APS.org 703-967-2751 American Physiological Society Source:Eurekalert

1 GOOD

Page: 1 2 3
Related biology news :

1. Lessons from evolution applied to national security and other threats