What aspect of a client’s lifestyle can significantly affect their exercise capacity?

The aspect of a client’s lifestyle that significantly affects their exercise capacity is indeed related to sleep patterns and stress levels. Quality sleep is essential for recovery, muscle repair, and overall energy levels, which can directly influence an individual’s ability to perform physical activities. When a person is well-rested, their cardiovascular and muscular systems function more efficiently, enhancing exercise performance.

Stress levels also play a critical role in exercise capacity. High stress can lead to fatigue, muscle tension, and decreased motivation, all of which can hinder a person's ability to engage in or enjoy physical activity. Stress can also affect hormonal balance and recovery rates between workouts, further impacting exercise capacity.

On the other hand, the focus on only diet, only exercise frequency, or work hours does not encompass the full spectrum of factors that influence exercise capacity. While these elements are important, they do not singularly encapsulate the holistic impact that sleep and stress have on an individual’s ability to engage in and benefit from exercise effectively.