Salbutamol intake and substrate oxidation during submaximal exercise

Abstract

In order to test the hypothesis that salbutamol would change substrate oxidation during submaximal exercise, eight recreationally trained men twice performed 1 h at 60% VO(2) peak after ingestion of placebo or 4 mg of salbutamol. Gas exchange was monitored and blood samples were collected during exercise for GH, ACTH, insulin, and blood glucose and lactate determination. With salbutamol versus placebo, there was no significant difference in total energy expenditure and substrate oxidation, but the substrate oxidation balance was significantly modified after 40 min of exercise. ACTH was significantly decreased with salbutamol during the last 10 min of exercise, whereas no difference was found between the two treatments in the other hormonal and metabolic parameters. The theory that the ergogenic effect of salbutamol results from a change in substrate oxidation has little support during relatively short term endurance exercise, but it is conceivable that longer exercise duration can generate positive findings.

Impact of salbutamol on muscle metabolism assessed by 31P NMR spectroscopy

“…While salbutamol had no significant effect on plantar flexors phosphorus compounds (which indirectly determine muscle metabolism) during an incremental and localized fatiguing task, it increased significantly endurance performance. Although some studies suggested that oral acute administration of β2‐agonist may improve muscle contractility and metabolism (Arlettaz et al., ; Crivelli et al., ), the present findings together with our previous results focusing on neuromuscular fatigue (Decorte et al., ) suggest that the ergogenic effect of β2‐agonists may arise from mechanisms beyond the muscle. Based on the potential central nervous system effect of β2‐agonists as shown by the stimulant effect of salbutamol for instance (Barrot et al., ), one could hypothesize that salbutamol‐induced changes in cerebral responses to exercise may underlie performance improvement.…”

“…It has been shown that β2‐agonists can induce a stimulation of hepatic glucose production and glucose release (Clutter et al., ), a stimulation of glycogenolysis and glycolysis with increased lactate and pyruvate release from tissues such as muscle (Rizza et al., ), a stimulation of lipolysis with increased glycerol and fatty acid release and lipid oxidation (Kendall et al., ; Schiffelers et al., ). Some studies reported no significant difference in total energy expenditure and substrate oxidation (based on gas exchange measurement during whole‐body exercise) following salbutamol administration, but the substrate oxidation balance might be modified during and after exercise (Collomp et al., 2000a,b, 2005; Arlettaz et al., ). Moreover, an acute therapeutic oral intake of salbutamol seems to improve performance during a supramaximal exercise together with significant modifications in both blood insulin and glucose concentrations as well as significantly enhanced blood lactate concentration during the recovery period (24).…”

“…These authors have also reported following oral salbutamol administration increased insulin levels and lactate removal rate that may be linked to improved endurance during submaximal exercise through an enhancement of the overall contribution to energy production of both aerobic and anaerobic metabolisms (Collomp et al., 2000a,b). Salbutamol appears however to have no effect on gas exchange (oxygen consumption, respiratory exchange ratio) during whole‐body submaximal and maximal exercise (Arlettaz et al., ; Elers et al., ). These contrasting results regarding the effects of β2‐agonists on metabolism are based on blood sampling and indirect calorimetry that cannot precisely and specifically assess changes in muscle metabolism.…”

High-dose inhaled terbutaline increases muscle strength and enhances maximal sprint performance in trained men

“…On the contrary, to the present observations, oral salbutamol (4-6 mg) has been shown to improve bike ergometer exercise performance at intensities ranging from 70 to 85 % of V O 2max (Collomp et al 2000;van Baak et al 2000). It has been suggested that performance enhancements associated with oral salbutamol are attributed to higher systemic availability of circulating glucose and increased glycolytic activity in skeletal muscles (van Baak et al 2000;Arlettaz et al 2009;Collomp et al 2000). However, while our plasma lactate data indicate elevated anaerobic energy production from exercising muscles with terbutaline, our observations show that terbutaline is without an effect on time-trial performance and may even have a negative impact on submaximal exercise performance by elevating energy expenditure (i.e., higher V O 2 ).…”

Effects of β2-adrenergic stimulation on exercise capacity in normal subjects

“…2-Adrenergic stimulant drugs used for the treatment of asthma are generally thought to enhance exercise performance, even though the evidence of it has been reported variably depending on doses, modes of administration and study designs (Malerba et al 1996;Carlsen et al 1997;van Baak et al 2000;Goubault et al 2001;Kindermann 2007;Le Panse et al 2007;Decorte et al 2008;Arlettaz et al 2009). …”