The Impact of the Ingestion of Dark Chocolate on the Cardiovascular Fitness of Moderately Active Individuals

Document Type


Degree Name

Master of Science (MS)


Human Performance Track

Date of Award

Summer 2017


Maintaining a moderate or high level of cardiorespiratory fitness (CRF) may reduce the risk of all-cause and cardiovascular (CVD) mortality in both men and women by as much as 3- to 6-times versus having a low CRF level. Among lifestyle factors, physical activity is the principal determinant of CRF; however, there are a number of pharmacological and nutritional aids purporting to aid athletes in reaching or maintaining a moderate or high CRF level. It was hypothesized that the ingestion of approximately 40 grams of commercially available dark chocolate (and the flavanols contained therein) for 14 days would significantly increase CRF, as measured by maximal oxygen uptake (VO2max), in moderately active adults compared to those who did not participate in the supplementation. Thirty-one participants (19 females/12 males, mean age - 22.3 ± 3.8 years, mean height - 169.4 ± 10.7 cm, mean weight - 71.9 ± 17.5 kg, and mean VO2max - 2.8 ± 0.9 L/min) were recruited and randomized into two groups. An experimental group (n = 20, 12 females/8 males) ingested dark chocolate for 14 days, while a control group (n = 11, 7 females/4 males) ingested white chocolate for 14 days. All participants completed a VO2max test on a treadmill (TrueOne 2400, Parvo Medics) before and after the period of supplementation. Although there was a significant difference (p = 0.01) in percentage change for VO2max between the experimental group (2.6% ± 3.1% change) and the control group (-1.6% ± 5.3% change), when the absolute difference in VO2max is measured, there is no significant improvement (p = 0.545) in the experimental group (0.08 ± 0.09 L/min) versus the control group (-0.06 ± 0.11 L/min). While a different group of participants (elite or specialized athletes, for example) may show a different result than seen here, for a moderately active individual, the best way to make significant improvements in CRF (and thus decreasing risks for all-cause and CVD mortality) remains increasing the level of physical activity.


Vipa Bernhardt

Subject Categories

Medicine and Health Sciences | Social and Behavioral Sciences | Sports Sciences | Sports Studies