Answer to Question 1
Regular physical activity is a core part of a healthy lifestyle that maintains health and delays aging processes. It increases oxygen delivery to organs and tissues, decreases biologic aging, improves cognitive functions, decreases chronic inflammation, and helps lower central body fat. Substantial health benefits result from performing moderate-intensity exercise for 150 minutes per week, or from 75 minutes of vigorous-intensity exercise weekly. Resistance exercise performed twice a week further enhances the benefits of regular exercise while increasing strength, muscle mass, and balance.
Answer to Question 2
Nutrient needs of older adults can be affected by physiological changes that may develop with increasing age. Decreased stomach acidity, for example, reduces absorption of vitamin B12, and the production of vitamin D in the skin upon exposure to sunlight is less than at younger ages. Aging is also accompanied by changes in body water composition, kidney function, and thirst perception. The changes can affect the need for water and the adequacy of water intake in older adults. Muscle mass also generally decreases as people age which increases the need for protein.
The logistic growth model does not describe all populations.
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