Terbutaline increases muscle mass at the expense of fitness

Definition: "An ergogenic aid is any substance or phenomenon that enhances performance "

08.09.2019

Terbutaline increases muscle mass at the expense of fitness
Strength athletes who use terbutaline, a beta-2 agonist that resembles salbutamol, build up more muscles, but in the longer term may also become less fit and lose stamina. Researchers from the University of Copenhagen discovered this in a human study. The dosages they used used are permitted in sport.

Study
The Danes divided 46 healthy and active young men aged 18-36, who moved 2-5 hours a week, into 4 groups.

The first group did not change his way of life [Habitual] for 28 days, and used a placebo [PLA] daily.

The men in the second group did not change his way of life either, but did use terbutaline [TER]. The men used an inhaler, which delivered 0.5 milligrams of terbutaline per puff. The men took 8 puffs every day. They inhaled every puff deeply, then held their breath for 5 seconds. In this way the body absorbs the maximum amount of terbutaline. The dose used is more than people with asthma normally need, but is just allowed in sports.

The men in the third group trained with weights 3 times a week [Resistance Training], and the men in the fourth group trained with weights and also used terbutaline.

Results
Terbutaline increased the increase in muscle mass in the men who did strength training.

Terbutaline increases muscle mass at the expense of fitness

The Danes got the men to cycle on a cyclometer as fast as they could, and determined the maximum amount of oxygen they could absorb [VO2max] [right]. The VO2max is the most important determinant of fitness.

There was a tendency to decrease, but it was not significant. However, when the researchers looked at the VO2max per kilo body weight, the decrease in VO2max was significant [left].

Terbutaline increases muscle mass at the expense of fitness

Mechanism
The decrease in VO2max was due to a reduced activity of enzymes involved in cells in combustion processes.

"In the present study, terbutaline treatment caused a non-significant decline in the content of IDH, the rate-limiting enzyme in the Krebs cycle," write the Danes. "Collectively, these data indicate that chronic treatment with beta2-adrenergic agonist may compromise oxidative capacity in skeletal muscle of humans."

Source:
Scand J Med Sci Sports. 2019 Aug 23. doi: 10.1111/sms.13544. [Epub ahead of print].

More:
Terbutaline tabs for a month: gain 2 kilos of muscle, lose 1 kilo of fat 09.06.2018
Taking eight puffs of terbutaline every day results in a kilo of extra muscle mass 4 weeks later 07.06.2018

Archives:
Beta-2-Agonists



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