The basal metabolic rate (BMR) is the base rate at which your body consumes calories for basic metabolic functions like maintaining internal temperature, repairing cells, pumping blood, powering muscles at rest, etc. In other words, it is the rate at which your body consumes calories when at rest.
Most diet and exercise programs focus on what kinds of food to eat, which exercises are best for weight loss and toning, etc. That's sensible, since both diet and exercise have to be adjusted to maintain a preferred weight range and a healthy body.
But adjusting calories and daily exercise times and types only makes sense when measured against a standard of some kind. Part of that standard is something called the basal metabolic rate.
What you eat and how you exercise are both topics that are important for achieving health and the type of physique you want. But, the basic equation remains the number of calories taken in minus the number of calories consumed equals what's left over to be stored in adipose tissues as fat.
Though every individual has a slightly different rate, the average is about 70 calories per hour. Slightly more when we're awake, slightly less when we are sleeping. Factors other than sleep influence the rate as well.
Internal body temperature is a big influence. For every 1/2 degree (Celsius) rise in body temperature, the BMR increases about 7%. This is easily seen in more extreme cases where we have a fever. If your internal temperature is about 4C (7F) above normal, the metabolic rate increases about 50%. This is obviously not a recommended way to increase calorie consumption.
Certain medications, such as anti-depressants can modify the BMR, leading to weight gain. As a result, anyone on a weight loss diet or exercise program should consult a physician about the potential impact of any prescribed medicines. Taking a prescription medication may be the best thing for your health, but knowing it could cause weight-gain can help reduce any guilt.
A certain amount of fat in the diet is healthy. EFAs (essential fatty acids) are needed for hormone regulation, electrical functions (which take place in the muscles, heart, brain and elsewhere) and other tasks.
After an injury, BMR can change (temporarily) while the body uses EFAs and proteins to rebuild damaged structures and create new tissue. Again obviously, you wouldn't want to injure yourself for the purpose of increasing it, but it's good to factor this in when monitoring calorie intake and consumption.
High-fat foods and refined sugars, however, can reduce BMR since they are lower in fiber and bulk. That slows down intestinal activity and the body will absorb more calories from them before passing through the digestive system. Getting the proper amount of vitamins and minerals can help regulate BMR to keep that process efficient.
Your basal metabolic rate is also greatly affected by the amount of muscle mass you have. The more muscle fiber, the higher your BMI as muscle, even at rest, burns significantly more calories than fat and other tissues. This is the reason that strength training is so important to a weight loss program. Aerobics and cardio exercises are good to a point, but if overdone can actually break down muscle tissues for energy which can be counter-productive to weight loss. An efficient exercise program will include both cardio and strength training.
BMR is determined chiefly by genetics and general physiological factors. A proper diet that balances fats, carbohydrates and proteins and regular, age-appropriate exercise will help you achieve your fitness and weight loss goals.
You can try this basal metabolic rate calculator to calculate your own BMR.
Body Mass Index (BMI) is a measurement of body fat based on height and weight that applies to both men and women between the ages of 18 and 65 years.
BMI can be used to indicate if you are overweight, obese, underweight or normal. A healthy BMI score is between 20 and 25. A score below 20 indicates that you may be underweight; a value above 25 indicates that you may be overweight.
You can calculate your BMI by using this BMI calculator.
When trying to reach your goals it's good to know what your basal metabolic rate is and that way you'll know how much you need to exceed it to achieve your desired results.