What is Basal Metabolic Rate?
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 are the twin partners that 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. The BMR is the base rate at which the body consumes calories for basic metabolic functions like maintaining internal temperature, repairing cells, pumping blood, powering muscles at rest, etc.
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%. Not the preferred method of increasing calorie consumption, obviously.
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 the prescription is generally best for health, but the added knowledge can help reduce any guilt from weight gain.
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.
BMR is determined chiefly by genetics and general physiological factors. A proper diet and regular, age-appropriate exercise will help you achieve your fitness and body goals.
When striving for those goals it’s good to know what the BMR is. That way you’ll know how much you need to be above it to achieve desired results.