Even when sleeping or sitting down, your body burns energy to keep vital processes running. You don’t just need energy to exercise. Your brain, heart, and lungs, as well as your digestion, all require energy.
Basal Metabolic Rate (BMR), or resting energy expenditure, is the energy your body uses at rest.
BMR is a tool that can help determine your total energy requirements and develop a daily nutrition plan to support your body best, considering all your daily activities and exercise. It is useful for determining your total energy needs and crafting a nutrition plan that best supports your body, especially when considering factors such as weight loss medication.
The Basal metabolic rate (BMR) is the energy your body uses at rest to keep you alive. It is also known as your “baseline metabolic rate.” It’s the number of calories your body would burn to maintain vital functions if you did nothing but lie down in a controlled setting for 24 hours.
How to Calculate BMR?
While it is only possible to calculate BMR accurately using laboratory equipment, you can estimate it using a formula. In 1990, the University of Nevada published a study that explained the BMR of women in the healthy, normal weight, and moderately obese range.
BMR (calories) = 10 x weight (kg) + 6.25 x height (cm) – 5 x age (y) – 161
The figure mentioned above is approximate and should only be used as a rough guide. BMR can vary from person to person due to genetics and bodily differences.
Factors Affecting Your BMR
Several factors can influence your Basal Metabolic Rate, which can change over time. These factors include lifestyle, environment, emotions, and life stage changes.
Temperature of the Environment:
Your body needs more energy to maintain its ideal temperature when the ambient temperature is either too high or too low.
Emotional Changes:
Cortisol and other hormones are released when the body is stressed. These hormones trigger your body’s “fight or flight” response, increasing heart rate and blood flow to muscles while also tensing up muscle tissue.
Weight Loss or Rapid Weight Loss?
Researchers have found that a diet low in calories and significant weight loss can cause the metabolic rate to drop. This can be an important consideration for weight loss medication, as these medications may affect metabolism and interact with the body’s natural processes.
Caffeine:
Caffeine can increase your Basal Metabolic Rate. It has also been shown to influence energy balance.
Infection or Disease:
You may feel tired when sick, but your body becomes more energetic when ill or injured. Fatigue is your body’s way of telling you to rest and slow down so that it can heal.
Body Size:
Larger bodies tend to have a higher BMR because they have more tissues and cells, which explains why BMR decreases with weight loss.
Body Composition:
Even at rest, lean muscle tissue burns more energy than body fat. Adipose tissue (fat) uses less energy than any other organ or tissue in the body. Strength training can increase lean muscle mass, thus supporting or increasing your BMR.
Gender and Age:
Due to their naturally higher muscle mass, men generally have a higher BMR. BMR also decreases with age, partly due to the loss of muscle mass. However, the decline is not as rapid as one might expect. According to Harvard Health, total and basal metabolic rates remain constant for most of adulthood, beginning to decrease around the age of 60.
What You Eat:
The macronutrient composition of your meals can influence your BMR. Protein is important not only for muscle repair and growth but can also increase your BMR by 20-30%. This compares with carbohydrates, which increase BMR by only 5-10%. Spices can increase energy expenditure, while nutritional deficiencies can slow metabolism.
Recent research shows that timing your meals doesn’t significantly affect your metabolism. The number and size of your meals have the greatest impact on weight gain or loss.
Exercise Increases Metabolism
Exercise directly impacts your daily energy expenditure. But does it also affect your resting metabolic rate?
Researchers found that BMR increased for 22 hours after moderate to high-intensity exercise. It may be due to factors like exercise-induced muscle repair and damage.
Strength or resistance training can also have a positive effect. In a 2000 study by Colorado State University, the resting metabolic rates of women aged 22 to 35 increased after intensive resistance training for 16 hours.
In a 2014 randomized controlled study, a group of healthy adults completed 96 resistance-training workouts over a period of nine months. Their results showed a significant rise in BMR. However, researchers noted that there are wide variations between individuals.
Do You Need to Eat Differently on Rest Days?
When strength training or high-intensity exercises increase metabolism, it’s natural to wonder if your diet should change on non-training days. Your nutrition should remain the same if you follow a regular exercise schedule. Your body will still work hard to recover and grow stronger. If you want to lose weight, you shouldn’t significantly reduce your food intake on rest days, as it may hinder your energy, recovery, and muscle growth.
Weight Loss and BMR
According to Mayo Clinic, metabolism rarely slows down enough to cause weight gain. A 2016 American Journal of Clinical Nutrition study found that BMR was not an indicator of weight loss.
Researchers discovered that adults with a low BMR did not gain more weight than those with a higher BMR. They concluded that variations in food intake and activity levels largely counterbalance BMR differences.
If you want to lose weight, understanding your BMR can help you create a balanced and sustainable diet and exercise plan, whether or not you’re using weight loss medication.
Conclusion
Understanding your Basal Metabolic Rate (BMR) is essential for managing your overall health and achieving your fitness goals. Knowing your BMR, you can tailor your diet and exercise plan to meet your body’s energy needs effectively. Whether you want to lose weight, gain muscle, or simply maintain a healthy lifestyle, understanding how BMR influences your metabolism can guide you in making informed choices. Factors like age, gender, body composition, and even weight loss medication can affect your BMR, so it’s important to consider these aspects in your approach to health and fitness. Remember, while BMR is a valuable tool, a balanced approach that includes proper nutrition, exercise, and rest is key to long-term success.
