Cocoa drinks can boost exercise resistance in middle age

Scientists in Liverpool have found that cocoa can increase oxygen uptake and make exercising easier for more sedentary people.

Cocoa contains bioactive compounds called flavanols, which a group of researchers from Liverpool John Moores University and Liverpool Hope University set out to test on a group of 'sedentary' but healthy adults aged between 40 and 60.

Daniel Sadler, Helen Jones, Claire Stewart and Dick Thijssen, from LJMU’s School of Sport and Exercise Science along with Simon Marwood of Hope University carried out the study, which has been widely reported in the national media.

During a series of trials over a five-week period the group was pushed to exhaustion using a lab-based exercise bike to establish each individual's power output and their VO2 peak — the maximum amount of oxygen the body can use during exercise.

Slows with age

They were then given either a daily 400mg cocoa flavanol supplement or a placebo over seven days before taking part in more tests to establish the time it takes for oxygen delivery to respond to exercise demands. The shorter the response the better you are able to perform in a given exercise.

Those who were given the flavanol supplement reduced this response time from around 40 seconds to 34, which researchers said was key because it 'exceeds the minimum physiologically relevant change' of around 5 seconds.

These compounds were found to be particularly helpful for middle-aged gym-goers because the rate at which oxygen consumption increases at the start of exercise slows with age.

Cocoa not chocolate

Although dark chocolate contains small amounts of flavanols, the team is not recommending eating a chocolate bar before exercise, as chocolate contains fats and sugars which may negate the benefits of bioactive compounds.

Instead they recommend consuming a shake with one and a half tablespoons of cocoa because natural cocoa powder contains an average of 34.6mg per gram of flavanol.

The paper Cocoa-flavanols enhance moderate-intensity pulmonary V˙O2V˙O2 kinetics but not exercise tolerance in sedentary middle-aged adults is published in the journal European Journal of Applied Physiology.


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