THE BLACK PAPER: LACTATE SHUTTLE

Exogenous lactate and fuelling for athletes

The idea behind consuming lactate is to provide a third fuel source alongside glucose and fructose, giving the body another route to support energy production during endurance exercise.

Studies confirm that lactate consumed in a drink can be absorbed and oxidised, meaning it is used to release energy. Research in trained cyclists has also found lower ratings of perceived exertion after calcium lactate supplementation. Together, these findings make lactate an interesting addition to sports nutrition.

What is lactate and how does it work

Lactate is an energy-carrying molecule produced during carbohydrate metabolism. It moves between cells and tissues through the lactate shuttle, supplying fuel to working muscles and the heart. Cells can convert lactate to pyruvate and use its carbon in the pathways that produce ATP, the “energy currency” for muscle contraction.

Exogenous lactate simply means lactate supplied from outside the body, through food or drink. Lactate Shuttle provides it as calcium lactate as a drink, alongside maltodextrin and fructose. The aim is to combine conventional high-carbohydrate fuelling with another usable energy source.

The evidence for using ingested lactate as fuel

Péronnet et al. (1997) studied six men cycling for two hours while consuming 25g of lactate, supplied as a mixture of salts, with 75g of glucose. Using carbon isotope tracers, the researchers followed the ingested fuels into exhaled carbon dioxide. Approximately 45% of the lactate was oxidised during exercise, compared with 48% of the glucose.

This is direct evidence that orally consumed lactate contributes energy during exercise. Lactate supplied around 2.6% of total energy expenditure in this protocol.

The evidence for rapid lactate use

Azevedo et al. (2007) studied six trained male cyclists consuming sports drinks before and during exercise. Labelled lactate appeared as exhaled carbon dioxide within the first five minutes of cycling, with the initial response peaking at 15 minutes, compared with 45 minutes for labelled glucose.

The result demonstrates that ingested lactate can become available for energy production quickly. The study used a different drink formulation containing a lactate polymer and small tracer doses, so its findings support the fuelling principle without of our calcium lactate drink.

The evidence for reduced perceived effort

Bordoli et al. (2024) studied 16 endurance-trained male cyclists in a placebo-controlled trial. Participants took calcium lactate 70 minutes before a session combining repeated 1 km and 4 km time trials with moderate-intensity cycling. Ratings of perceived exertion, or RPE, were significantly lower with calcium lactate.

In practical terms, participants rated the exercise as less demanding. This is an encouraging finding for athletes undertaking sustained exercise with repeated hard efforts. However, completion times did not improve.

How we have applied the science

FLYCARB Lactate Shuttle combines maltodextrin and fructose with calcium lactate in a convenient drink powder. Each 600 g pouch contains 24 x 25g scoops, with approximately 3g of calcium lactate per scoop. Calcium lactate includes both calcium and lactate.

Our serving guide is two scoops below 60 kg, three scoops from 60-80 kg and four scoops above 80 kg, mixed with approximately 500 ml of water. We designed Lactate Shuttle for use within a wider fuelling plan, particularly during longer sessions and endurance events.

We recommend starting to drink the lactate drink within the hour before the event, and continuing during.

Lactate’s ability to supply energy is established and its potential to make demanding exercise feel easier are exciting! These are the foundations of Lactate Shuttle, and we acknowledge that more research is needed to demonstrate a clear performance benefit.