Adding a spoonful of table sugar into water can boost the endurance and stamina of long-distance athletes and avoid tiredness during big physical events, according to a new study. In the study, which was carried out at the University of Bath, the researchers studied the impact of endurance exercise on liver glycogen levels and tested what could be done to prevent fatigue. Their findings were published the American Journal of Physiology – Endocrinology & Metabolism.
For the study, the team examined how different carbohydrates could act on the tiredness levels of fourteen experienced long-distance male cyclists, who were given sucrose- and glucose-based drinks. They found that ingesting carbohydrates in the form of either glucose or sucrose prevents the decline in liver glycogen ‘carbohydrate stores’ which in turn, prevents tiredness.
“The carbohydrate stores in our liver are vitally important when it comes to endurance exercise as they help us to maintain a stable blood sugar level,” explained Dr Javier Gonzalez, lead researcher of the study. “However, whilst we have a relatively good understanding of the changes in our muscle carbohydrate stores with exercise and nutrition, we know very little about optimizing liver carbohydrate stores during and after exercise.”
Both sucrose and glucose are important carbohydrates, which are quickly absorbed by the body in order to produce energy. They are known as ‘simple sugars’. The only difference between the two is that glucose is a monosaccharide, while sucrose – which is formed when glucose and fructose combined – is a disaccharide.
An increasing number of energy and sports-performance drink now use sucrose – mixtures of glucose and fructose- to provide energy during exercise, but many still rely on glucose. The researchers warn that drinks based on glucose only could produce gut discomfort. So they suggest that sucrose-based alternatives, or sugar in water, can help make exercise easier.
“Our study showed that ingesting carbohydrates during exercise can prevent the depletion of carbohydrate stores in the liver but not in muscle. This may be one of the ways in which carbohydrate ingestion improves endurance performance.”
“We also found that the exercise felt easier, and the gut comfort of the cyclists was better, when they ingested sucrose compared to glucose. This suggests that, when your goal is to maximise carbohydrate availability, sucrose is probably a better source of carbohydrate to ingest than glucose.”
Too much sugar can be bad, so the team recommends consuming up to 90 grams of sugar per hour – diluted to 8 grams sugar per 100 ml for an optimal performance during exercise which lasts over two and half hours.
[Source: University of Bath, American Journal of Physiology – Endocrinology and Metabolism: Ingestion of Glucose or Sucrose Prevents Liver but not Muscle Glycogen Depletion During Prolonged Endurance-type Exercise in Trained Cyclists, Image via Shutterstock]