Which of the following factors increases BMR?

• A. Growth, infection, fever, extreme temps, elevated hormones
• B. Aging, fasting, sleep
• C. Exercise
• D. Diet, dehydration

Answer: (D)

BMR rises when the body needs more energy at rest due to certain demanding conditions. Growth and tissue synthesis require more energy, so BMR goes up. Infections and fever accelerate the body's immune response and heat production, both increasing resting energy use. When the body works to regulate temperature in extreme cold or heat, energy needs climb as well. Hormonal signals, especially thyroid hormones and catecholamines, further boost metabolic rate, pushing BMR higher.

Dietary intake mainly affects energy expenditure through the thermic effect of food, a temporary rise after eating, but this is not the baseline resting rate. Fasting and dieting tend to lower BMR over time as the body adapts to conserve energy. Dehydration does not increase BMR; it may affect measurements or overall physiology in other ways, but it doesn’t raise the resting metabolic rate.