Do Athletes Have a Higher RMR? Understanding the Science of Metabolic Rate in Sports Nutrition

October 14, 2025 •

4 min read

Resting metabolic rate (RMR) accounts for 40–60% of an individual's total daily energy expenditure, making it a critical component of energy balance for all individuals. Given their demanding training regimens and distinct body compositions, many people wonder: Do athletes have a higher RMR? The answer is yes, largely due to their higher percentage of metabolically active muscle mass compared to sedentary individuals.

Quick Summary

Athletes generally exhibit a higher resting metabolic rate (RMR) primarily due to their greater lean body mass, which requires more energy to maintain. The type of sport and energy availability also influence metabolic rate. This increased RMR necessitates higher caloric intake to maintain energy balance, support performance, and optimize recovery.

Key Points

Lean Body Mass is Key: Athletes have a higher RMR primarily because muscle tissue is more metabolically active and requires more energy to maintain at rest than fat mass.
Sport Specificity Matters: The type of sport and training volume influence RMR, with athletes in power-based sports often exhibiting higher values than endurance athletes.
Energy Balance is Critical: If caloric intake is insufficient to meet high energy demands, RMR can be suppressed as a survival mechanism, negatively impacting performance and health.
RMR Influences Nutrition Needs: A higher RMR necessitates a greater overall caloric intake and careful macronutrient planning to support intense training and promote recovery.
Personalization is Optimal: Predictive RMR equations may not be accurate for athletes, making direct measurement via indirect calorimetry the gold standard for determining individual energy needs.
Metabolic Adaptations Occur: Regular, long-term exercise training leads to metabolic adaptations, such as increased mitochondrial activity, which contribute to a higher RMR.
Gender Differences are Influenced by Body Composition: While men often have a higher absolute RMR than women, these differences become insignificant when normalized to lean body mass, demonstrating that body size and composition are the main factors.

What is Resting Metabolic Rate (RMR)?

Resting Metabolic Rate (RMR) represents the energy your body expends to perform basic, involuntary functions while at rest, such as breathing, blood circulation, and cell production. It is not a static number, but rather a dynamic metric influenced by a variety of factors. For athletes, understanding and measuring RMR is a fundamental step toward developing a personalized and effective nutrition strategy. While equations exist to estimate RMR, they often fall short for athletic populations, as they don't always account for the higher muscle mass and other metabolic adaptations seen in trained individuals.

The Direct Link Between Lean Body Mass and Higher RMR

The most significant reason for an athlete's higher RMR is their elevated lean body mass, primarily muscle tissue. Muscle is far more metabolically active than fat tissue. It requires more energy to maintain at rest, which elevates the baseline caloric burn. This difference in body composition is a primary driver of the higher resting energy expenditure observed in athletes, especially those engaged in resistance training or power-based sports. A study on bodybuilding athletes confirmed that they have a significantly higher RMR compared to non-athletes with less muscle mass. This metabolic advantage is not limited to bodybuilders; a large cohort study of collegiate athletes found men had a higher absolute RMR than women, but when normalized for body mass and fat-free mass, the differences were no longer significant, reinforcing that body size and composition drive these variations.

Other Factors Influencing an Athlete's RMR

Beyond muscle mass, several other factors contribute to an athlete's metabolic rate:

Sport Discipline: Different sports place different demands on the body, which can influence RMR. For example, handball players have been shown to have a higher RMR compared to cyclists, likely due to their higher skeletal muscle mass.
Training Intensity and Volume: The volume and intensity of training can influence RMR. Endurance athletes, for instance, may see adaptations in mitochondrial density and enzyme activity that affect their metabolic rate. High-intensity interval training (HIIT) can also lead to a prolonged increase in RMR after a workout, a phenomenon known as excess post-exercise oxygen consumption (EPOC).
Energy Availability: This is a crucial concept, especially for female athletes, relating to the balance between energy intake and exercise energy expenditure. When energy availability is low (not enough fuel for the body's needs), the body may suppress RMR as a protective measure to conserve energy, leading to a condition known as Relative Energy Deficiency in Sport (RED-S).
Hormonal Profile: Hormones like testosterone and thyroid hormones play a significant role in regulating RMR. These hormonal profiles are influenced by intense training and recovery status.
Post-Exercise Metabolism (EPOC): After a demanding training session, an athlete's metabolism remains elevated for a period of time, continuing to burn extra calories. This is part of the body's recovery process to restore physiological systems to their resting state.

Comparing Athlete vs. Non-Athlete RMR

To illustrate the metabolic differences, consider the characteristics of a trained athlete versus a sedentary individual. While not universal, the following table highlights general patterns based on body composition and training status.


Feature	Athlete (Higher Lean Mass)	Non-Athlete (Typical Body Composition)
Body Composition	Higher percentage of muscle mass; lower body fat percentage	Lower percentage of muscle mass; higher body fat percentage
Absolute RMR	Often higher due to a greater mass of metabolically active tissue	Lower, reflecting less overall metabolically active tissue
RMR Relative to Body Weight	May have a higher RMR per kilogram, but this can be influenced by metabolic efficiency	Lower RMR per kilogram, as less energy is needed for maintenance
Response to Exercise	Experiences a notable and prolonged EPOC, leading to more calories burned post-workout	Less pronounced EPOC, with metabolism returning to baseline faster
Energy Requirements	Requires significantly higher daily caloric intake to support training and recovery	Lower caloric requirements to maintain body weight
Metabolic Flexibility	More efficient at utilizing different fuel sources (carbohydrates, fats) based on training demands	Less metabolic flexibility; relies more on standard fuel pathways

The Implications for Athlete Nutrition

An athlete's higher RMR, combined with the caloric demands of intense training, means their nutritional needs are substantially greater than those of sedentary people. A diet plan for an athlete must be meticulously designed to meet these elevated energy requirements to prevent a negative energy balance, which can lead to negative metabolic and performance outcomes. Personalizing nutrition for athletes is paramount, and direct measurement of RMR via indirect calorimetry is considered the gold standard for accuracy.

The athlete's diet should be periodized to match training phases, adjusting macronutrient intake to support high-intensity days, moderate-intensity days, and rest days. For instance, a higher carbohydrate intake is often necessary on heavy training days to replenish muscle glycogen stores, while a high-protein intake is crucial for muscle repair and adaptation. Monitoring RMR and adjusting nutrition accordingly helps ensure optimal energy availability, mitigating the risk of RED-S and maximizing performance potential.

Conclusion

In short, do athletes have a higher RMR? Yes, predominantly because their rigorous training routines build and maintain a higher percentage of lean body mass. This greater metabolic engine means they burn more calories at rest than sedentary individuals, necessitating a higher overall caloric intake to support their physiology. Understanding RMR is a fundamental part of sports nutrition, allowing for precise fueling strategies that optimize energy balance, recovery, and peak athletic performance. By focusing on body composition, training demands, and energy availability, athletes can leverage their metabolic advantage to achieve their goals. For further information on the topic of athletic performance and metabolism, exploring studies published by the National Institutes of Health can be beneficial.

Frequently Asked Questions

An athlete's resting metabolic rate (RMR) is higher primarily due to their greater lean body mass, particularly muscle tissue. Muscle is metabolically more active than fat, meaning it burns more calories even at rest, thus elevating the overall RMR.

Yes, RMR can fluctuate significantly depending on training intensity, volume, and energy availability. Periods of high-intensity training can lead to a higher RMR, while low energy availability can suppress it as a metabolic adaptation.

RMR is influenced by sport discipline due to variations in muscle mass. Athletes in sports that require significant strength and power, like bodybuilding or handball, often have a higher RMR than those in endurance sports, such as cycling.

A higher RMR is generally beneficial as it indicates a more active metabolism and often corresponds to greater lean body mass. However, if energy intake does not match the high expenditure, it can lead to health issues like Relative Energy Deficiency in Sport (RED-S).

For athletes, a direct RMR test using indirect calorimetry is the most accurate method. Standard prediction equations often underestimate the metabolic needs of trained individuals due to their higher muscle mass.

Higher RMR is often associated with a lower body fat percentage, especially when RMR is expressed relative to body weight. Body mass and fat-free mass are strong predictors of RMR in both male and female athletes.

If an athlete significantly restricts calories, the body perceives it as a threat and enters a state of metabolic adaptation, where RMR is suppressed to conserve energy. This can have adverse effects on performance, recovery, and overall health.