Oxford Brookes lecturer on nutrition for athlete's at the Olympics
Clare Shaw is a a senior sports science lecturer at Oxford Brookes University, currently studying nutrition and it's impact on athletic performance.
With the Olympics underway, the focus for athletes is on getting fitter, faster, and stronger, but at what cost?
Clare Shaw, a Senior Sports Lecturer at Oxford Brookes University, and a practitioner on the Sport is researching the impact of low energy availability in athletes for her PhD.
So what is low energy availability?
Low energy availability occurs when dietary energy intake does not meet exercise energy expenditure, leading to an energy imbalance.
For athletes, optimal energy for physiological functioning is defined as 45 kcal/kg fat free mass (FFM) per day, where as energy availability of less than 30 kcal/kg FFM per day is a debated threshold for low energy availability in females and 25 kcal/kg FFM per day for males.
The nutritional requirements of athletes vary greatly depending on factors such as physical activity intensity, age, sex, training status, sports-specific demands, and environmental conditions.
Low energy availability can be nutritionally planned for and controlled for a performance goal or achieving an ideal body composition or weight.
When low energy availability occurs intentionally or inadvertently over a prolonged duration, potentially serious health and performance consequences can follow.
Energy expenditure in athletes can range between 2500-8000 kcal per day, and in some ultra-endurance sports it can be in excess of 10,000kcal/day.
This is compared to the recommended NHS intake for non athletes of 2,000 calories a day for women and 2,500 calories per day for men.
What are the immediate and long-term consequences of low energy availability?
Within five days of low energy availability, the consequences become evident as the body’s systems become impaired.
Prolonged low energy availability leads to more significant physiological adaptations and dysfunctions, affecting health and performance.
Issues include impaired glucose and lipid metabolism, reduced immunity, sleep disturbances, and decreased training response, muscle strength, endurance, recovery, cognitive performance and skill.
Long term, persistent disruptions to physiological systems can lead to impaired bone health, reproductive dysfunction, decreased energy metabolism, gastrointestinal issues, and reduced cardiovascular and haematological health.
Overall, low energy can lead to a decline in sports performance and an increased risk of injury.
Sports with high prevalence rates of low energy availability include endurance sports like running and cycling, aesthetic sports such as ballet, dance, and gymnastics, and weight class sports like rowing and combat sports.
Any sport with extreme exercise energy expenditure, power-to-weight ratios, or desired leanness can put athletes at greater risk.