Beetroot and aerobic endurance
A study examined the effect of beetroot juice consumption in patients with heart failure and preserved ejection fraction. Exercise intolerance is the cardinal clinical feature of this particular form of heart failure. One key factor responsible for low exercise tolerance seen in elderly people with heart failure and preserved ejection fraction is thought to be low levels of the vasodilator nitric oxide.
In the initial study, patients received a single, acute dose of nitrate-rich beetroot juice or a nitrate-depleted placebo beetroot juice. In a second phase, patients consumed nitrate-rich beetroot juice for an average of 7 days.
An improvement in submaximal aerobic endurance of 24% after 1 week of daily nitrate dosing was observed, but no effect of the single, acute dose of nitrate compared to placebo. Since the average age of the patients was 69 ± 7yrs, the authors concluded that 1 week of daily dosing with nitrate significantly improves submaximal aerobic endurance in elderly patients with heart failure and preserved ejection fraction. It may be that persistent dosing results in an increase of nitrite in the tissues that enable localised benefits with exercise, due to enhanced nitric oxide generation associated with exercise-induced changes in environmental conditions. This includes low levels of oxygen in the body.
Eggebeen, J., et al., (2016). One week of daily dosing with beetroot juice improves submaximal endurance and blood pressure in older patients with heart failure and preserved ejection fraction, JACC: Heart Failure, vol. 4, No. 6, 428–437.