Final answer:
Maximum oxygen uptake generally decreases with age both at rest and during exercise. Maximum heart rate (HR) for an individual can be estimated by subtracting their age from 220. Exercise increases HR and stroke volume, enhancing cardiac output significantly above the resting rate.
Step-by-step explanation:
In adulthood, the pattern for maximum oxygen uptake, also known as cardiac reserve, varies with one's age whether at rest or during exercise. At rest, newborns may have a resting heart rate (HR) of approximately 120 beats per minute (bpm), but this rate gradually decreases until young adulthood and begins to increase again as one ages. During exercise, a young adult's HR may increase to 150 bpm, and their stroke volume (SV) can increase from 70 to approximately 130 mL, thereby increasing their cardiac output (CO) to about 19.5 L/min, which is a significant elevation from the resting rate.
As an individual ages, the maximum HR declines, which can be estimated by subtracting the person's age from the maximal value of 220 bpm. Therefore, a 40-year-old is expected to hit a maximum HR of approximately 180 bpm, while a 60-year-old might achieve a maximum HR of 160 bpm. It's important to note that this is a simplified estimation, and maximum HRs can vary depending on several factors including fitness level, genetics, and overall health.