All are features of exercise except

Options

A. left shift of hb -`O_(2)` dissoication curve
B. increased blood supply to muscle
C. increase stroke volume
D. increase `O_(2)` extraction

Answer

To solve the question "All are features of exercise except," we need to analyze the options provided and determine which one does not align with the physiological changes that occur during exercise.

### Step-by-step Solution:

1. **Understand the Hemoglobin Oxygen Dissociation Curve**:
- During exercise, the body requires more oxygen to produce ATP, leading to an increase in carbon dioxide and lactic acid levels. This results in a rightward shift of the hemoglobin oxygen dissociation curve, indicating that hemoglobin releases oxygen more readily to the tissues.

2. **Evaluate Increased Blood Supply to Muscles**:
- Exercise increases blood flow to the muscles to meet the higher oxygen demand. This is a typical response during physical activity.

3. **Consider Increased Stroke Volume**:
- Stroke volume, which is the amount of blood ejected by the left ventricle with each heartbeat, increases during exercise. This is due to the heart pumping more efficiently to supply the body with oxygen-rich blood.

4. **Assess Increased Oxygen Extraction**:
- During exercise, the muscles extract more oxygen from the blood to meet their energy demands. This is another characteristic feature of physical activity.

5. **Identify the Incorrect Feature**:
- The first option mentions a "left shift of hemoglobin oxygen dissociation curve." This is incorrect because, during exercise, the curve actually shifts to the right, not the left. The left shift typically occurs under conditions of high oxygen availability and low carbon dioxide, which is not the case during exercise.

### Conclusion:
The feature that is not associated with exercise is the "left shift of hemoglobin oxygen dissociation curve."

### Final Answer:
**All are features of exercise except**: Left shift of hemoglobin oxygen dissociation curve.

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