ABSTRACT
We aimed to determine the effects of a betalain-rich concentrate (BRC) of beetroots, containing no sugars or nitrates, on exercise performance and recovery. Twenty-two (9 men and 13 women) triathletes (age, 38 ± 11 years) completed 2 double-blind, crossover, randomized trials (BRC and placebo) starting 7 days apart. Each trial was preceded by 6 days of supplementation with 100 mg·day-1 of BRC or placebo. On the 7th day of supplementation, exercise trials commenced 120 min after ingestion of 50 mg BRC or placebo and consisted of 40 min of cycling (75 ± 5% maximal oxygen consumption) followed by a 10-km running time trial (TT). Subjects returned 24 h later to complete a 5-km running TT to assess recovery. Ten-kilometer TT duration (49.5 ± 8.9 vs. 50.8 ± 10.3 min, p = 0.03) was faster with the BRC treatment. Despite running faster, average heart rate and ratings of perceived exertion were not different between treatments. Five-kilometer TT duration (23.2 ± 4.4 vs 23.9 ± 4.7 min, p = 0.003), 24 h after the 10-km TT, was faster in 17 of the 22 subjects with the BRC treatment. Creatine kinase, a muscle damage marker, increased less (40.5 ± 22.5 vs. 49.7 ± 21.5 U·L-1, p = 0.02) from baseline to after the 10-km TT and subjective fatigue increased less (-0.05 ± 6.1 vs. 3.23 ± 6.1, p = 0.05) from baseline to 24 h after the 10-km TT with BRC. In conclusion, BRC supplementation improved 10-km TT performance in competitive male and female triathletes. Improved 5-km TT performances 24 h after the 10-km TT and the attenuated increase of creatine kinase and fatigue suggest an increase in recovery while taking BRC.
Subject(s)
Athletic Performance , Beta vulgaris/chemistry , Betalains/therapeutic use , Fatigue/prevention & control , Fruit and Vegetable Juices , Plant Roots/chemistry , Sports Nutritional Physiological Phenomena , Adult , Athletes , Betalains/analysis , Bicycling , Cross-Over Studies , Double-Blind Method , Fatigue/metabolism , Fatigue/rehabilitation , Female , Food Handling , Fruit and Vegetable Juices/analysis , Humans , Male , Middle Aged , Muscle Fatigue , Oxygen Consumption , Physical Exertion , Running , SwimmingABSTRACT
This study aimed to determine the effects of a betalain-rich concentrate (BRC) of red beets, containing antioxidant and anti-inflammatory properties, on performance and exercise-related muscle damage. Thirteen (25.3 ± 5.4 years) competitive male runners completed two double-blind, cross-over, randomized trials (BRC and control) separated by seven days. Each trial was preceded by six days of supplementation with 100 mg of BRC or control. On the seventh day, exercise trials commenced 150 min after supplementation with 50 mg BRC or control and consisted of 30 min of treadmill running (77 ± 4% VO2max) followed by a 5-km time trial (TT). During exercise at the same intensity, BRC resulted in a 3% lower heart rate, a 15% lower rate of perceived exertion (RPE) and a 14% lower blood lactate concentration compared to the control (p = 0.05). Five-kilometer TT duration (23.0 ± 4.2 versus 23.6 ± 4.0 min) was faster in 10 of the 13 subjects, and RPE was lower (p < 0.05) with the BRC treatment compared to the control. Lactate dehydrogenase, a marker of muscle damage, increased less from baseline to immediately and 30 min after the 5-km TT with the BRC treatment, despite no differences in subjective measures of muscle soreness and fatigue. In summary, BRC supplementation improved 5-km performance time in male competitive runners.
