Hypertrophic effect of inhaled beta2 -agonist with and without concurrent exercise training: A randomized controlled trial.
S JessenJ OnslevA LemmingerV BackerJ BangsboMorten HostrupPublished in: Scandinavian journal of medicine & science in sports (2018)
Due to a high prevalence of asthma and exercise-induced bronchoconstriction in elite athletes, there is a high use of beta2 -adrenoceptor agonists (beta2 -agonists) in the athletic population. While anabolic in rodents, no study has been able to detect hypertrophy in humans after chronic beta2 -agonist inhalation. We investigated whether inhaled beta2 -agonist, terbutaline, alters body composition and metabolic rate with and without concurrent exercise training in healthy young men. Sixty-seven participants completed a 4-week intervention of daily terbutaline (8 × 0.5 mg) or placebo treatment without concurrent training (habitual; n = 23), with resistance (n = 23) or endurance (n = 21) training 3 times weekly. Before and after the interventions, participant's body composition was determined by dual-energy X-ray absorptiometry and resting metabolic rate and substrate oxidation by indirect calorimetry. Terbutaline increased lean body mass by 1.03 kg (95% CI 0.29-1.76; P < .05) and 1.04 kg (95% CI 0.16-1.93; P < .05) compared to placebo in the habitual and resistance training group, respectively, but had no effect compared to placebo in the endurance training group [-0.56 kg (95% CI -1.74-0.62; P > .05)]. Fat mass, bone mineral content, and resting metabolic rate did not change differently between treatments with the intervention. Daily inhalation of terbutaline in near-therapeutic doses induces skeletal muscle growth. This observation should be a concern for antidoping authorities.
Keyphrases
- body composition
- resistance training
- bone mineral density
- skeletal muscle
- dual energy
- randomized controlled trial
- physical activity
- high intensity
- computed tomography
- locally advanced
- double blind
- insulin resistance
- adipose tissue
- cystic fibrosis
- chronic obstructive pulmonary disease
- placebo controlled
- squamous cell carcinoma
- postmenopausal women
- type diabetes
- middle aged
- high resolution
- nitric oxide
- magnetic resonance imaging
- atomic force microscopy
- mass spectrometry
- image quality
- allergic rhinitis