Basal Metabolic Rate (BMR) is the amount of energy the body requires to maintain essential physiological functions while at complete rest. These functions include breathing, circulation, cell production, nutrient processing, and maintenance of body temperature. BMR contributes to approximately 60-75% of total daily energy expenditure in individuals with a sedentary lifestyle.

Factors Influencing BMR

BMR is influenced by multiple factors, including:

• Body size and composition (lean muscle mass increases BMR)

• Age (BMR tends to decrease with age)

• Hormonal status (thyroid hormones increase BMR)

• Environmental temperature

• Nutritional state and health conditions

Analysis of Conditions Affecting BMR in Given Options

1. Awake and resting: The person is at rest but awake and maintaining homeostasis. BMR is relatively higher during wakefulness compared to sleep because of brain activity and slight muscle tone.

2. Prolonged starvation: Starvation causes the body to conserve energy by lowering BMR significantly. The body reduces metabolic processes to preserve energy stores, leading to the lowest BMR among typical physiological states.

3. Sleep: BMR decreases during sleep typically by 10-15% compared to awake resting state but less than in starvation.

4. Higher environmental temperature: Increased environmental temperature can decrease BMR slightly because the body requires less energy to maintain core temperature compared to cold. However, the effect is generally less than the energy-conserving mechanisms during starvation.

Conclusion

Among the given options, prolonged starvation leads to the lowest Basal Metabolic Rate because the body adapts by significantly reducing energy expenditure to conserve energy stores.

Hence, the correct answer is:

(2) Prolonged starvation