Proper sleep is perhaps, at once, the most important, and the most overlooked factor in improving health and fitness. I have pondered in fact, to what degree all research on exercise is tainted because for the most part, a majority of the population is actually sleep deprived. To my knowledge, this particular variable is rarely if ever factored in to most research. Since proper recovery is acknowledged as critical and manipulating intensity, frequency and volume of exercise to achieve said recovery is the subject of much exercise research and debate, I speculate whether much of the minutiae that people argue about would be far less relevant, if all research subjects got a sufficient quantity of quality sleep on a regular basis. Alternatively, I would be grateful if anyone could point me in the direction of research on exercise that compares results based on hours of sleep between a sleep deprived group and one that is not. This article by Drew Baye does a great job of addressing this important issue.