5 Things Every Cyclist Needs To Know About Resting Metabolic Rate

Resting metabolic rate refers to the amount of energy the body requires at rest to perform it’s basic functions, ranging from maintaining core temperature and breathing to growth and repair.

 It’s an important part of metabolism, health and performance and a key driver of our energy needs as cyclists, so in this week’s blog, we’ll take a look at five key things that every cyclist should know about resting metabolic rate…

1. It can be the most significant contributor to energy expenditure – Our metabolism is made up of 4 key components.

• Non-Exercise Activity Thermogenesis (NEAT) – This is the energy we expend in day-to-day living, in effect, all activity that isn’t considered exercise, ranging from the energy required to get out of bed, switch on the kettle and
• Thermic Effect Of Feeding – This is generally the smallest component and makes up around 10% of your total energy expenditure. It is the energy required to digest and process the food you consume on a day to day basis. It is influenced by the composition of the diet (for example, protein has a much greater thermic effect than fat) and the total amount of energy you consume on a daily basis.
• Exercise Energy Expenditure – As cyclists, this the the additional energy we expend on the bike and during any other training we complete.
• Resting Metabolic Rate can typically account for 60-80% of daily energy needs. However, as cyclists, this contribution may drop as low as 20-40% due to the sheer magnitude of energy expenditure on a bike. If we take a World Tour Pro Cyclist who can expend in excess of 6000kcals on the bike alone, with a resting metabolic rate of around 2000kcal the contribution of resting metabolism is significantly less.

2. It’s difficult to measure accurately – The measurement of resting metabolic rate requires costly equipment and strict controls to ensure an athlete is fasted and rested. Whilst it is possible for athletes to spend a few hundred pounds and get RMR measured in a lab, we can use prediction equations (of which there are many!), to estimate it, and these can often be accurate and mean there is little need to have it professionally measured. Equations like the Harris & Benedict or the Cunningham equation are commonly used when looking to predict an athlete’s energy needs.
   
   There are two terms often used: basal and resting metabolic rate. Whilst they are effectively the same thing, there are subtle differences in how they are measured (one requires an overnight stay in a lab so the cyclist can be measured immediately on waking, whilst the other allows for cyclists to get to the lab before being measured)
   
   
3. It’s not static – Whilst many of us think of resting metabolic rate as a static number, it can change on a daily basis. For example, during periods of low energy availability, where a cyclist’s energy intake is less than their total requirements, the body can compensate for this by reducing the resting metabolic rate to compensate, which can have negative impacts on health. A reduction in RMR is often used to indicate that an athlete has been under fuelling. In contrast, lots of high-intensity exercise can lead to excessive post-exercise oxygen consumption, which can drive up RMR, and in female athletes, different stages of the menstrual cycle
   
   
4. It’s heavily influenced by muscle mass – When calculating resting metabolic rate, tissues such as muscle and organ’s are very metabolically active and therefore require a lot of energy and significantly contribute to our resting energy needs. Many of the equations take into account an athletes lean mass, age, height and weight.
   
   
5.  It decreases with age - As we get older, we typically see a decline in our muscle mass, which is  a likely cause of a reduction in our resting energy needs. Maintaining muscle and activity can help to offset this and and reduction is likely relatively small. 

Want to learn more about your energy needs and how to fuel your training and competition better? Within Fuel The Ride Academy we teach you all you need to know about how to caclulate your energy needs and how tobuild your own nutrition plan around these needs. Check out the links at the top of the page for more information. 

Coach Ben