Speed of performance work rates number of problems attempted

Speed of performance [75], work rates ([17,24,98][87]), number of problems attempted [4,13,41]; Webb and Levy, 1984) and choice of tasks of various degrees of difficulty [7,79] have been used to determine performance effort. The subjective experience of effort is the sense of perceived exertion when performing beyond the fulfillment of basic task requirements [55] and the available energetic resources.
Historical background—Capacity, sleep loss and effort The impact of sleep loss on the availability of resources and the application of effort to accomplish goals has been of interest since the early days of sleep research. Researchers studying sleep deprivation approached the topic in three primary ways. They considered how performance was maintained through compensatory effort and evaluated the subjective reports of the expenditure of effort under conditions of sleep loss. The absence of performance deficits following sleep loss was considered to result from the application of compensatory effort [25,34,76] and assumed that without additional effort directed toward alert and focused engagement, poor performance would result. In one early study, the author and his wife, the only participants in the study, reported that they EZLink Sulfo-NHS-SS-Biotin Kit had to apply greater effort to perform efficiently on days following sleep loss. They proposed that voluntary ‘effort’ compensated for the subjective experience of impairment and surmised that expended effort increased in proportion to the amount of sleep lost. To prevent impairment on mental arithmetic, a person having slept 6h instead of 8 would have to apply 25% greater “energy expenditure” [57].
Theoretical and applied value of examining capacity, sleep loss and effort
Hypotheses regarding capacity, sleep loss and effort Robinson and Hermann [76] hypothesized that sleep loss negatively affected one’s ability to perform and that additional effort through “muscular or ideational means” was necessary and responsible for the maintenance of performance when sleep was absent. Two more recent hypotheses have attempted to explain the role of effort under sleep loss conditions. The first hypothesis posits that sleep loss causes sleepiness, impairs the arousal mechanism and reduces the supply of energy needed to power arousal, perceptual processes, motivation and effort. The outcome of this arousal deficit is a reduction in the desire to perform, a decrease in effort and performance impairments [101,102]. Sleepiness and the urge for sleep caused by sleep loss compete with interest in completing tasks [5], but motivational factors such as feedback can restore arousal, energy and motivation, and impact effort and performance at least for a short-time [81,54] as cited by Odle-Dusseau et al. [65]). A second hypothesis suggests that energy resources and capacity are lost during sleep deprivation and these losses are responsible for the observed performance deficits. Under well-rested circumstances, the brain consumes the resources necessary to attend to, process and react to stimulation. However, under the influence of a stressor, such as the loss of sleep, the energy supply required for high quality performance is insufficient or unavailable. The effort mechanism can compensate for an insufficient energy supply if the person is aware of their current or potentially substandard performance. This awareness either leads to the mobilization of additional resources needed to sustain performance or the reduction of demands so that the discrepancy between the intention to perform well and actual performance will be aligned [89,50]). Hockey et al. [43] applying this model, proposed that when stress and fatigue caused by sleep loss threatens performance, participants will shift to less-demanding tasks to accommodate the decreased capacity.
Capacity and sleep loss
Sleep loss, cortical changes and effort
Sleep loss, physiology and effort