Energy Availability: How to Stay Healthy While Training Hard
In our last post, we introduced the concept of Physical Activity Level (PAL) as a measure of training volume. This metric, unique to Calorify, is the most holistic view of your overall lifestyle as it relates to your baseline metabolism. Today, we introduce the concept of energy availability (EA), which takes this concept to the next level by making it even more specific to training.
We all require energy to perform the tasks required to live a healthy life. As athletes, we increase these demands through our training workload. This leads to the fundamental question:
How many calories do I require to be healthy?
Enter Energy Availability. Energy availability is defined as the number of calories you have left (after accounting for exercise and training) relative to your body size. More precisely:
Energy Availability = (Calories eaten – exercise calories burned)
Lean body mass (kg)
Why does Energy Availability (EA) matter?
Think of everything in your life that isn’t training for your sport. It takes calories! Want a healthy immune system? Calories. Good bone density? Calories. Mental health? Calories. Energy availability is THE fundamental measure of how much energy you have left over after training to do the things you need to do to live a happy and healthy life.
What is Relative Energy Deficiency in Sport (RED-S)?
Sports take energy. Lots of it. Particularly at the elite levels, and often in endurance sports like cycling, swimming, running and rowing, athletes can spend up to 30 hours per week in training. That’s a lot!
Accentuating this issue is that these power-to-weight ratio sports involve not only increasing fitness while also minimizing weight. All of this accentuates the issues that these athletes can face…they’re often limited in the calories that they have left over to be healthy. In short, they have limited energy availability.
Low energy availability is THE underlying issue with the all-too-common issues of Overtraining Syndrome (OTS) and RED-S.
Relative Energy Deficiency in Sport (RED-S)
RED-S is a syndrome caused by low energy availability that leads to poor health and reduced athletic performance. Common symptoms are: fatigue, weight loss, missed periods (female), low libido (male), frequent sicknesses, mental health effects and more. RED-S was often referred to as Female Athlete Triad in the early days though now it’s clear that these issues can affect male athletes as well. The Female Athlete Triad is composed of disordered eating, amenorrhea (loss of periods) and osteopenia or osteoporosis (low bone density).
The effects of RED-S can be devastating. And they can be much longer to recover from than other overuse injuries like stress fractures. Multiple Olympians we know have taken 6-12 months to recover from the effects of RED-S.
Low energy availability is a metabolic crisis worth avoiding at all costs.
How much Energy Availability do I need to avoid overtraining issues?
30 non-exercise calories per kg of lean body mass. It’s that simple. 35 calories may be a more conservative target. In these cases, that translates to roughly 1800 – 2100 calories for a 150 lb 10% body fat individual. That’s not total calories (which Calorify measures with a great deal of accuracy), but calories left after exercise.
Calorify not only measures total calories eaten, but also tells you how much room left you have in your energy budget to increase your training before reaching the red zone (or how much you should reduce your training to get back into the safe zone).
How does this relate to Physical Activity Level (PAL)?
This is not fully understood, but put simply: the higher the physical activity level, the lower the energy availability must be. Given that researchers have identified long term sustainable physical activity level to be ~2.5x an individual’s basal metabolic rate, it may also be the case that individuals training at this high activity level may also be running into energy availability issues. At Calorify, we’re on the front lines of investigating this question, and we hope to work alongside researchers to drive the science forward.
What can Calorify’s EA measurement do for me?
Currently, RED-S and other overtraining conditions are diagnosed by a doctor looking at an athlete’s overall health, medical history, training history etc. To date, there exists no objective measurement of energy availability. Doctors must estimate an athletes’ calories eaten by asking the athlete. Research has repeatedly shown that individuals are not very accurate at counting their own calories, let alone recalling them in the past!
Calorify has brought to market a measurement of energy availability that doesn’t rely on the athlete’s word for it. Simply taking a Calorify test, regularly weighing in and providing exercise calorie data (e.g. from a smartwatch, powermeter, etc) allows Calorify to quantitatively measure energy availability.
If you’d like to monitor your energy availability and stay out of the red zone, reach out…we’d love to help you reach your goals in a safe and sustainable manner.
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