Question

The severity of workload is considered heavy when heart rate of worker is

• A. \(< 100\text{ beats/minute}\)
• B. 100-125 beats/minute
• C. 125-150 beats/minute
• D. \(> 150\text{ beats/minute}\)

Hint:

Heart rate brackets:
Light: $< 100$ bpm
Moderate: $100-125$ bpm
Heavy: $125-150$ bpm
Very Heavy: $> 150$ bpm.

Answer 1

The Correct Option is C

Step 1: Understanding the Concept:
Physical workload intensity is physiological graded according to working heart rate, oxygen consumption rate, and energy expenditure.
Key Formula or Approach:
\[ \text{Heart Rate Range (bpm)} \longrightarrow \text{Workload Severity Classification} \]

Step 2: Detailed Explanation:
According to the standardized ergonomic classification (Christensen Varghese & Saha for Indian agricultural workers):
1. Light Work: Heart rate \(< 100\text{ beats/min}\) (Energy expenditure \(< 10\text{ kJ/min}\))
2. Moderate Work: Heart rate \(100 - 125\text{ beats/min}\) (Energy expenditure \(10 - 15\text{ kJ/min}\))
3. Heavy Work: Heart rate \(125 - 150\text{ beats/min}\) (Energy expenditure \(15 - 20\text{ kJ/min}\))
4. Very Heavy Work: Heart rate \(150 - 175\text{ beats/min}\)
5. Extremely Heavy Work: Heart rate \(> 175\text{ beats/min}\)

Step 3: Final Answer:
Hence, workload is considered heavy when the heart rate is 125-150 beats/minute, matching option (C).