Beetroot juice could potentially boost ‘high intensity’ sports performance, say scientists.
From the Department of Human Movement Sciences at Maastricht University, Dr. Naomi Cermak said her team had published two studies linked to the effects of beetroot juice as an ergogenic aid.
The first study discovered a significant improvement in 10km time trial performance after six days of supplementation with 140ml of concentrated beetroot juice containing 8 millimoles (mmol) of nitrate daily.
Cermak noted that nitrate – present in high levels in beetroot juice – was the most likely ingredient responsible for beetroot’s juice’s undoubted ergogenic effects.
Dietary nitrate worked by lowering the ‘oxygen cost’ at a given intensity during exercise, Cermak explained, as your muscles used oxygen more efficiently.
However, she did say it was unclear how the process works and whether it was primarily responsible for the ergogenic effects; dietary nitrate also lowered blood pressure and improve mitochondrial function, so perhaps multiple mechanisms were at play.
But the team’s most recent publication involving acute supplementation (one 140ml dose of juice with 8mmol of nitrate 2.5 hours prior to racing) found no effect on one hour time trial performance among well-trained cyclists.
This evaluated result compares with a previous study in which acute supplementation (6.2 mmol in 500ml of juice) improved 4km and 16.1km cycling time trial performance.
Cermak said more work was required since there were no acute effects but only suggestions that beetroot juice could be an effective exercise aid if drunk regularly.
She said: “We don’t know whether dietary nitrate is effective only at certain exercise intensities or certain exercise durations”.
For example, in the first six-day study subjects cycled 10km in 14-18 minutes, while the acute study saw subjects cover around 40-50km in one hour.
The latter race was much longer but performed at a lower intensity.
She added: “Thus we do not know yet whether the ergogenic effects of dietary nitrate depend on the duration of supplementation or the actual exercise itself”.
