Just one capsule of Rhodiola is enough to improve your stamina
Endurance athletes who take one capsule of Rhodiola rosea an hour before training or before a competition perform better. In 2004 physiologists at the Katholieke Universiteit Leuven in Belgium discovered that the stamina and oxygen uptake of active students rose immediately after ingesting 200 mg Rhodiola extract.
Rhodiola rosea is a succulent plant. Russian researchers who gave extracts of Rhodiola roots to lab animals in the second half of the twentieth century discovered that these enabled the animals to withstand heavy physical and mental stress better. Rats in the Russian experiments were able to swim for longer, for example. [Bull Exp Biol Med. 2003 Dec;136(6):585-7.]
The Belgian researchers wondered whether Rhodiola rosea also works immediately after taking a dose, so they did an experiment with 24 fit students.
The researchers first determined the subjects' endurance capacity, before they had taken anything, and then repeated the test twice: once 1 hour after the students had taken 200 mg Rhodiola, and once again after they had taken a placebo. The students had to cycle on a cyclometer, and increase the amount of energy they produced by 20 watts each minute.
The Belgians used a product made by the German company Finzelberg, which consisted of 3 percent rosavin and 1 percent salidroside.
The supplement extended the time to exhaustion by an average of 3 percent. In one test subject the supplement even extended the time by 9.7 percent.
The effect reminded the researchers of amphetamines. Amphetamines become less effective if you take the same dose continuously. When the researchers gave their students Rhodiola rosea for 4 consecutive weeks, they noticed that the ergogenic effect decreased, although not by a statistically significant amount. All measurements in the table below were taken 1 hour after administering the supplement.
So Rhodiola works, and it's not necessary to take it every day. If you take a capsule 1 hour before you start running, cycling or rowing you'll notice the benefits. Continuous use adds nothing.
There are no signs of benefits of Rhodiola rosea for strength athletes. The American army did trials nearly ten years ago to see whether Rhodiola increased strength. It doesn't. [Metabolism. 2007 Aug;56(8):1111-7.]
Rhodiola may be interesting for life extenders though: biologists in the Netherlands discovered that the nematode Caenorhabditis elegans lives 15 percent longer if exposed to Rhodiola extract.
Int J Sport Nutr Exerc Metab. 2004 Jun; 14(3): 298-307.
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Supplementation For Endurance