Figure 2
From: Physical exertion and working efficiency of reforestation workers
Sample heart rates. Sample individual heart rate responses during 10 hours of tree planting work. Panels A & B: experienced tree planters (4 and 5 seasons experience respectively). Panels C & D: inexperienced tree planters (both during first season of work). Dashed lines on panels A & C denote one work period or "bag-up" for comparison purposes.