The effects of ephedrine on the development of fatigue in a prolonged driving-related task

Abstract

The eects of ephedrine on the development of fatigue in a prolonged driving-related task were investigated using three independent measures. Subjects (n 15) received either ephedrine (60 mg) or a placebo before carrying out a 3-way divided attention task for an uninterrupted 4 h period, during which cardiac inter-beat interval was monitored. A battery of psychomotor tests and two questionnaires were completed before and after the 4 h session and oral temperature, blood pressure and heart rate were also recorded. A saliva sample was taken at 4 h for ephedrine assay. The performance of the placebo group on the prolonged task deteriorated over time, whereas that of the ephedrine group improved. In placebo subjects, there was a progressive decrease in heart rate, an increase in heart rate variability (HRV) and an increase in the peak log spectral power of the blood pressure frequency component of HRV. Deterioration of performance on the test battery and questionnaires con®rmed that fatigue had developed. The mean salivary ephedrine concentration after 4 h was 0 . 08 mg/ml (0 . 03 SEM). The deterioration in performance in the placebo group indicated the development of fatigue which was partially oset by a single therapeutic dose of ephedrine.

Cognitive methods for assessing mental energy

“…This occurred, in part, because the FDA received many reports of serious adverse events resulting from the consumption of ephedra-containing products (FDA 1997;Shekelle et al 2003). Few behavioral studies have examined the effects of ephedra or ephedrine on cognitive performance and mood, although ephedrine had stimulant-like effects on vigilance in a task designed to simulate prolonged operation of a motor vehicle and increases subjective alertness, as assessed by mood questionnaires (Mooleenar et al 1999).…”

Cognitive Effects of Nutraceuticals

“…A single 60 mg dose of ephedrine maintains focus during a driving-related task (Moolenaar et al, 1999). The major active ingredients are ephedrine and pseudoephedrine, stimulants that raise blood pressure and heart rate.…”

Effects of ephedra on autonomic nervous modulation in healthy young adults

“…Moreover, HRV has been used in a variety of disciplines to diagnose illness and has been found to correlate with severity of illness (Task Force of the European Society of Cardiology and the North American Society of Pacing and Electrophysiology, 1996;Kleiger et al, 2005). Moolenaar et al (1999) reported that the ingestion of ephedrine, the main ingredient of ephedra, is able to change HRV measures in subjects carrying out driving-related task; however, there is no information available regarding the effects of ephedra on HRV. To better understand the actions of ephedra so that the negative effects can be avoided, the present study investigates the effects of ephedra in healthy young adults in terms of their autonomic nervous modulation using power spectral analysis of the HRV as the tool.…”