The effects of exercise intensity (a), fluid temperature (b), glucose concentration (c), and ingested volume (d) on the rate of gastric emptying.
Note. From “Factors Limiting Gastric Emptying During Rest and Exercise” by D.L. Costill and B. Saltin, 1974, Journal of Applied Physiology, 37, p. 681. Copyright 1982 by American Physiological Society. Adapted by permission.
Sitting Yoga Poses Photo Gallery
Click on Photos for Next Sitting Yoga Poses Gallery Images
Three drinksBrake Time, Body Punch, and Gatoradestudied by Coyle et al. (1978).
The amount of liquid emptied by the stomach increases with increasing volume ingested (Exercises 4.4d) and was maximum in Costill and Saltin’s (1974) study at an ingestion rate of 2.4 L/hr. This critically important finding, which has been completely overlooked by exercise physiologists and athletes, will be discussed in detail subsequently.
Costill and Saltin (1974) did not study the effects of increasing the osmolality of the ingested solution by adding electrolytes. However, hypertonic solutions are known to delay gastric emptying (see Exercises 3.1).
More recent studies indicate that many additional factors influence the rate of gastric emptying. Both dehydration (Neufer et al, 1989a) and severe environmental conditions (>35 °C dry bulb temperature, 20% relative humidity; Neufer et al, 1989a) impair gastric emptying, but running at exercise intensities less than 75 % V02max is associated with increased rates of gastric emptying (Neufer et al, 1986, 1989b). Training appears not to influence the rate of gastric emptying (Rehrer et al, 1989a), which is also the same during cycling and running at the same exercise intensities (Neufer, 1989b; Rehrer et al, 1990).